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EYE AND VISION RESEARCH DEVELOPMENTS
THE OPTIMAL TECH THE BEGINNER’S GUIDE TO OPTOMETRIC AND OPHTHALMIC TECHING
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EYE AND VISION RESEARCH DEVELOPMENTS
THE OPTIMAL TECH THE BEGINNER’S GUIDE TO OPTOMETRIC AND OPHTHALMIC TECHING
KELI B. O’CONNOR
Copyright © 2022 by Nova Science Publishers, Inc. https://doi.org/10.52305/BQNU4632 All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. We have partnered with Copyright Clearance Center to make it easy for you to obtain permissions to reuse content from this publication. Simply navigate to this publication’s page on Nova’s website and locate the “Get Permission” button below the title description. This button is linked directly to the title’s permission page on copyright.com. Alternatively, you can visit copyright.com and search by title, ISBN, or ISSN. For further questions about using the service on copyright.com, please contact: Copyright Clearance Center Phone: +1-(978) 750-8400 Fax: +1-(978) 750-4470 E-mail: [email protected].
NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers’ use of, or reliance upon, this material. Any parts of this book based on government reports are so indicated and copyright is claimed for those parts to the extent applicable to compilations of such works. Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the Publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. Additional color graphics may be available in the e-book version of this book.
Library of Congress Cataloging-in-Publication Data ISBN: H%RRN
Published by Nova Science Publishers, Inc. † New York
To Killian and Joey, thanks for putting up with me.
Contents
Preface
........................................................................................ ix
Acknowledgments ................................................................................xiii Introduction
....................................................................................... xv
Section I
General Eye Care .......................................................... 1
Chapter 1
Patient Care ................................................................... 3
Chapter 2
Anatomy and Physiology .............................................. 9
Chapter 3
The Exam ..................................................................... 17
Chapter 4
Refraction .................................................................... 35
Chapter 5
Cataracts ...................................................................... 45
Chapter 6
Glaucoma ..................................................................... 49
Section II
Subspecialties............................................................... 53
Chapter 7
Cornea .......................................................................... 55
Chapter 8
Retina ........................................................................... 67
Chapter 9
Neuro-Ophthalmology ................................................ 79
Chapter 10
Oculoplastics ................................................................ 89
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Section III
Diagnostic Testing ....................................................... 99
Chapter 11
Visual Fields .............................................................. 101
Chapter 12
Imaging ...................................................................... 111
Chapter 13
Optics ......................................................................... 123
Conclusion
..................................................................................... 135
Appendices
..................................................................................... 137
References
..................................................................................... 153
Additional Resources .......................................................................... 159 About the Author ................................................................................ 163 Index
..................................................................................... 165
PREFACE I have a confession to make. I am not the biggest fan of refracting. There are plenty of other things I would rather do. Tonometry, OCTs, visual acuities, Schirmer’s, you name it I don’t mind. Refractions? Just not my cup of tea. Don’t get me wrong, I love the math behind it. The theories and laws of light fascinate me. Eyeglasses are one of my favorite things on the planet and I literally cannot get enough of them (I have over a dozen pairs at home as I write this). Refracting patients is my least favorite part of ophthalmology because it’s so subjective and I can’t control what the patient’s response will be. What they like today, might not be the same as what they like tomorrow, especially if their blood sugars are wonky, and that’s completely different from every other objective test that is performed in the field. But you know what? I do them. There are two reasons for this: 1) it’s not about me and patients deserve to have prescriptions that they can see from without the hassle of having to come back several times over for glasses checks because I rushed it the first time and 2) I do it because I am a part of a team. I am not the sole tech at my practice; I am one of dozens of technicians at a university hospital. If I don’t do my job then someone else has to do my job for me and, simply put, that isn’t fair.
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We all go to work every day, just like our coworkers, and no one should have to pick up the slack because a fellow team member isn’t putting in the effort. Lazy techs bring down morale and make everyone jealous, because if that tech doesn’t have to work, why should I? Poor morale and laziness create a domino effect and in a short time, an entire practice could find itself suffering. We don’t want to hate our jobs, so why be the reason someone else hates theirs? Although we may work for ourselves first, be it for compensation and perhaps even professional fulfillment, we work for our patients and our doctors, next. Physicians bring in the money that pays our bills and how we work is a representation of them and the practice that they are a part of. If I am constantly late, rude, and ignorant (in both the literal and colloquial meanings) patients are going to assume the same about the doctor that they are about to be examined by. If the patient does not like the physician or the atmosphere of the clinic, they are more likely to look for a new doc. Fewer patients translate to less money coming into the practice. Less money coming in means cutbacks. Cutbacks mean employees get let go. Who do you think management will let go first? The model employee who is always on time that patients and doctors alike love or the tech who doesn’t really care about their job and lets others pick up their slack? Maybe the doctor you work for is extremely difficult. Although I have, for the most part, been very fortunate with the doctors that I have worked for, I have worked for individuals who make the Grinch look like the Dalai Lama. It can seem impossible to keep up the motivation to work hard when you are constantly being reprimanded for things that are out of your control (one doctor once reprimanded me for having two patients not show up for their scheduled appointments), but do what you can until you can’t take it anymore and go look for a job more deserving of you. Some of my closest friends in the world are current and former coworkers of mine. When we spend eight hours a day with the same people, they become like family. I spend more time with my coworkers than with my real-life family sometimes. This situation might not be ideal, but why purposely try to make that situation any worse? You are only going to stress out your coworkers, which will give you further stress, and,
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in turn, will stress your coworkers even more. The circle never ends. Stress at work equals resentment and drama. And I don’t think you’ll want to play into the drama cycle. I’ve seen it spin out of control and it can get ugly.
ACKNOWLEDGMENTS Writing this book has always been kind of a dream of mine, but I wouldn’t have even had the time to think of writing if it wasn’t for my husband George Petner, COA. I couldn’t ask for a better life partner/coworker. I have been very fortunate to have worked for many esteemed doctors in ophthalmology. Dr. Tomás Alemán, MD is a true hero amongst ophthalmologists, and I have been incredibly lucky to work under his guidance. Likewise, there is no way I would have the knowledge, professionalism, or discipline that I have if not for the wonderful Dr. Madhura Tamhankar, MD. Speaking of amazing physicians, I need to thank Dr. César Briceño, MD for being the wonderful person that he is. Dr. Briceño I adore you. I need to extend a gigantic thank you to Dr. James Boyland, OD because he believed in me when other members of the practice we worked for didn’t. He also let me ride on his motorcycle on sunny days, which is cool. Dee Whalen and Lauren Culbertson, ABOC are two of the sweetest women I know and they have been a source of support for many, many years. Similarly, Nicole Wallace, COT and Abbey Ostermann, COT have been my support group any time there was drama in and outside of work. Dave Roff, ABOM is my opticianry hero and I chalk my love of optics up to having him as an amazing mentor.
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Speaking of mentors, huge shout out and thank you to Jacqueline Pullos, COMT for taking me under her wing when she didn’t have to and had nothing to gain from the experience. She is an amazing person and working with her has been fantastic and insightful. Finally, I need to thank my sons, Killian and Joey, not only out of moral obligation but because they are two of the funniest, intelligent, and compassionate people I know. I owe so much to these boys. If it wasn’t for them, I wouldn’t be nearly as motivated as I’d been writing this book. Keli B. O’Connor, COMT, ABOC
INTRODUCTION Welcome to eyecare. If you are reading this book, it probably means that you are about to start a new job as an optometric or ophthalmic assistant. If that’s the case, congratulations on getting the job! If you are already an assistant but you’re interested in finding out more about a specific subspecialty, like retina or neuro-ophthalmology, good for you, too there is plenty of info in here for you. Either way, from one tech to another, thank you for taking the steps to learn more about the field. Your coworkers, managers, and doctors will appreciate your drive. The eyes are vastly different than any other part of the body and you may feel a little overwhelmed with so much new information coming at you so quickly. Because of this, I wanted to create a guidebook for eye health professionals, so beginners have a launch site when they first start out in the field. Sure, there are textbooks for certifications out there, but if you’ve never been exposed to eyecare, reading one can leave you feeling like a kindergartener reading Gray’s Anatomy. I know because I was once that sad adult kindergartener who struggled with figuring out which eye muscle did what while filtering out heavier stuff like the sympathetic versus parasympathetic systems. I could have used something exponentially more down to earth to study from in the beginning.
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With this book, you can start with the basics and then work your way up to the more challenging concepts as you progress throughout your career. Becoming certified is one of the best things you can do for yourself as an eye tech, and I fully encourage you to apply and study for the exams. Get those fancy letters after your name. But expecting someone to jump right into the Certified Paraoptometric or Ophthalmic Assistant exams without teaching them how to use their parachute can be scary, to say the least. Although this book isn’t necessarily a study guide for the CPO or COA tests necessarily, my hope is that the information presented in this book warms you up for the heavier stuff and primes you to start studying for those certs or enrolling in a formal technician program. Working with patients requires patience. They are real people with real lives and real problems just like you and me. You can be the world’s best technician, but you can still have a tough time with some people. There may be hiccups along the way but having a foundation of knowledge to work from helps. Be inquisitive, find answers to questions you don’t know the answer to and keep improving your skillset. You owe it to your future self. Optometric and ophthalmic assisting is a fun and rewarding job, whether you’ve never worked for a doctor or you’re making the transition over from medical assisting. People will always need eye tests and, even as online vision checks pop up, there will always be brick and mortar offices for patients to have legitimate exams. Optometrists and ophthalmologists aren’t going anywhere, and they need a strong team to support them. Do your best and rise to meet challenges instead of dodging them – your patients are counting on you. And so are your doctors who need you to figure out why the printer isn’t working.
SECTION I GENERAL EYE CARE
Chapter 1
PATIENT CARE “THE CUSTOMER IS ALWAYS RIGHT” If you ever had the misfortune of working in retail sales, you have probably heard (and disagreed with) this motto. In medicine, instead of customers, we have patients, but the saying still applies. As ophthalmic personnel, patient care and satisfaction is our job. Whether on the phone or face-to-face, treating everyone with respect and helping them to the best of our abilities is key in making sure that our patients remain our patients instead of seeking out new doctors from a different practice. When patients come back for follow-up care, patients are happier. When patients are happier, doctors are happier. When doctors are happier, they pay better. See what I’m getting at? Of course, there are many variables about the eye exam that we cannot control. Copays, insurance, long wait times and dilation are pain points within the visit that we are unable to change, but we can give our patients a heads up about the nature of their visit and what it involves so they know what to expect. If the doctor is running behind, be upfront about it and if your patient requires photography or additional testing prior to seeing the doctor, explain what the test is going to be, so they have less anxiety and are better prepared for it. Some people may be afraid of going to the doctor, but many are downright terrified of going to the eye doctor.
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This all may seem to be basic info for some of you, and you may be tempted to rush through workups or skip steps of the exam when you’re busy. Don’t do that. Treat everyone as if they were your own family member because they are someone out there’s child, sibling, spouse, or parent. More importantly, each patient is somebody. If you wouldn’t want to be treated badly or rushed, respect your patient enough to do better for them.
KEEPING PATIENTS IN THE LOOP One of the most important things to keep the patient informed about is the eye drop portion of the visit. Every single patient that you work up should be told the same thing, no matter if this is their first exam with the practice or if they come in every four weeks for an injection: “I’m going to give you four drops today. The first one is a numbing drop that will prevent you from feeling the other three as much. It may sting a little at first, especially if your eyes are on the drier side, but it goes away in a few seconds and burns a lot less than the other drops without it. Your eyelids might feel a little heavy for about 15 minutes or so. “The next drop is a yellow dye- this is just so I can check your pressures under the blue light.”
If the patient has any questions about anything, answer them before proceeding. Once pressures are checked (and the patient is cleared for dilation), continue: “These last two drops are your dilating drops. They work together, take about 20 or 30 minutes to kick in and can last about four to six hours. You may get a little light-sensitive or blurred especially up-close during that time. If you don’t have any sunglasses, we have disposable ones at the front desk for you when you go to check out.”
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This script can change when a handheld tonometer is being used to check pressures, only one of the dilating drops is being instilled, or dilation is skipped all together, but keeping the patient in the loop goes a long way for keeping them calm. If this looks like a lot to say, know that it can be done. Start telling the patient while before retrieving the dops, as the patient is handed a tissue, and the bottles are being opened. It takes virtually no additional time for the exam and everyone is more comfortable because awkward silences while prying someone’s eyes open is the worst. Besides, we as ophthalmic personnel are legally required to tell patients what medications we are administering to them. Regulations and all.
SOFT SKILLS Not all of the skills we need for our profession are technical. Our attitudes and how we perform our work tasks are arguably just as important as being able to accurately manifest or take a reliable OCT. Being able to connect with patients and doctors takes a great deal of social skills, patience, and composure that comes with some experience with patient care. Personal enrichment in the form of certification or soft skill development is virtually guaranteed to earn more respect from your physicians and colleagues. Work ethics, problem-solving, communication, and leadership are all drivers of success. Constantly improving these skill sets will help you and everyone around you in the long run. Educating yourself and working toward being a better communicator helps build your doctors’ confidence in you. It won’t guarantee a better work relationship with your doc, but it certainly won’t hurt it.
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TOUGH PATIENTS When the patient is happy, the doctor is happy. When you work toward making the clinic run smoothly, you can please them both. As previously mentioned, there are going to be times when the patient can be challenging. Patients can be mean, rude, or deviant in our care. I’ve had patients make lewd remarks to me, blame all their worldly troubles on my existence and unzip their pants and pee in front of me. Handle what you can, respectfully verbalize the exam room boundaries, and inform your attending physician or manager. If things escalate, it is ultimately their responsibility to handle the situation and determine the course of action for the offending patient. On occasion, you may have to deal with sexual harassment from your patient. This is never okay. But sometimes this abusive behavior can be explained similarly to our angry patients. Some people feel that they are in a very vulnerable state during their exams and may harass staff and doctors as a way of asserting dominance. Elderly folk, those with mental impairments and those on certain medications cannot necessarily help their words or actions and do not realize that they have done anything wrong after abusing staff. Some people just harass to be jerks. Whatever the case, if and only if you are comfortable doing so, tell the patient that they cannot continue to behave in this manner. If you don’t feel comfortable doing this, let your manager or doctor do this for you. Whether you handle a situation like this on your own or have help from a coworker, always report such incidences to your physician. If the troublesome behavior continues, the office may decide to discharge the patient from the practice. Often, patients can be belligerent because they are scared or anxious. In the past, I had a recurring patient that was abrasive and mean-spirited to everyone during his examination, from workup tech to photographer to scribe. The front desk staff had no idea that this man treated the technicians this way because he was the happiest and most thoughtful person in the room by the time he was ready to check out. This drastic change in attitudes was solely attributed to his exam
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and bilateral intraocular injections; once his visit had come to an end, he had nothing left to fear and transformed into the most pleasant person anyone could ever meet. Healthcare, ESPECIALLY eye healthcare, can be very scary for people. We only get one pair of eyes (sometimes less) and the thought of us not having them can be terrifying. Everyone reacts to their fears differently and it’s important we give our patients the same level of care regardless of their temperament.
Conclusion Most patients are not problematic. The golden rule goes a long way, so treat all your patients how you’d like to be treated if the roles were reversed. Someone’s bad day could be the result of a death in their family or recent diagnosis that is weighing heavily on them. We are all human and deserve to be treated civilly. Patient care is not for the faint of heart, but it is rewarding. Helping people see is a gift that not just anyone can do and being in this field is often well worth it beyond our paychecks.
Chapter 2
ANATOMY AND PHYSIOLOGY Before we talk about how to care for eyes, we need to know exactly what we’re up against. Our eyes are small but complex, with many parts that work together for us to see properly. If one piece of the puzzle is missing or malfunctioning, the eye can lose vision or experience a great deal of pain. Although the many parts of the eye – the cornea, retina, optic nerve, its muscles – can be treated individually at times, it’s best to keep in mind that these are all working cogs in the same machine. The eye itself can be broken down into eight major components: the cornea, sclera, anterior chamber, vitreous and retina, the optic nerve, extraocular muscles, external eye, and the orbit.
CORNEA The cornea is made of five layers and is responsible for most of our vision. Before you learn anything else, note that there are 5 layers to the cornea: the epithelium, Bowman’s layer, stroma, the Descemet’s membrane, and endothelium.
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Figure 1. Basic ocular anatomy: 1) Cornea. 2) Lens. 3) Sclera. 4) Anterior chamber. 5) Posterior chamber and vitreous. 6) Retina. 7) Optic nerve.
Epithelium: Outermost layer. Think skin, like epidermis Bowman’s Layer: Second layer, like how B is the second letter of the alphabet. Stroma: Thickest, centermost layer. Thin word for a thick layer. Descemet’s Membrane: Fourth layer, like D is the fourth letter of the alphabet. Endothelium: The most interior layer but the end of the cornea. If you’re better off with mnemonics, try remembering “Every Big Strong Dog Eats”. Whatever helps you with it, knowing the five layers that make up the cornea and what they are called is key when studying for any certification exam and in working in ophthalmology, like when comparing abrasions to lacerations. In 2013, researchers found a potential sixth layer between the stroma and the Descemet’s membrane, but many scientists are still on the fence about it.
SCLERA The white of the eye, or sclera, is covered in a translucent layer called the conjunctiva, both of which meet the cornea in the area called the limbus. The sclera is rigid and gives the eye its shape; its toughness prevents the eye from rupturing unless the injury is especially serious.
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Superficial injuries, like subconjunctival hemorrhages, often look much worse than they actually are. Inflammatory conditions like scleritis and episcleritis look better but feel worse for patients and often require topical or systemic medication for treatment.
ANTERIOR CHAMBER The anterior chamber houses the lens and the uvea, a group within the eye that consists of the iris, choroid and ciliary body. Lenses can be thought of as less delicious Peanut M&Ms, whereas the candy shell is the coating, the chocolate is the cortex and the peanut center is the nucleus. Irises, as you may already know, are the colored part of the eye, the choroid is the vascular layer of the eye that extends throughout the retina and the ciliary body helps produce the fluid inside of the anterior chamber called the aqueous humor. The ciliary body is also responsible for changing the shape of the lens to focus at different distances.
VITREOUS In the middle of the eye is a body of jelly-like fluid called the vitreous. The vitreous media is encapsulated and attached to the inner eye in various locations at its base.
(a) Rod cell. Figure 2. (a) Rod cell. (b) Cone cell.
(b) Cone cell.
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RETINA The retina is composed of ten different layers, eleven if you count the vitreous, sandwiched together. If we omit the vitreous, which retina physicians also treat, the layers of the retina from innermost to outermost are the inner limiting membrane, the nerve fiber layer, the ganglion cell layer, the inner plexiform layer, the inner nuclear layer, the outer plexiform layer, the outer nuclear layer, the outer (external) limiting membrane, the photoreceptors, and the retinal pigment epithelium¹⁷. The photoreceptor layer is comprised of the rods and cones, the cones giving us color and central vision while the rods give us our night vision.
Figure 3. Retinal Lasagna. Above: Rendering of a retinal OCT scan. At right: Inset of retinal layers. 1) Inner limiting membrane. 2) Nerve fiber layer. 3) Ganglion cell layer. 4) Inner plexiform layer. 5) Inner nuclear layer. 6) Outer plexiform layer. 7) Outer nuclear layer. 8) Outer limiting membrane. 9) The photoreceptor layer. 10) Retinal pigment epithelium.
1 2 3 4 5 6 7 8 9 10
The macula is an area within the retina that is responsible for our central vision. It is home
The is an the retina that for our to themacula cone cells andarea evenwithin minuscule damage to is theresponsible area, be it from a cyst or hole, can cause central vision. visual It is home to the cone andiseven minuscule damage substantial impairment. At thecells center the foveal depression (the to clinical macula), seen as a small dip in OCT images, followed by the parafovea, and perifovea. Further the area, be it from a cyst or hole, can cause substantial visual impairment. out from that is the peripheral retina, sectioned off by areas called the mid-periphery and far-periphery, where our rod At the center is theDamage foveal depression (theperipheral clinical macula), asscotomas, a small or blind spots, in our cells take over. to parts of our retinal canseen cause dip in OCT images, followed by the parafovea, and perifovea. Further out peripheral visual field or even trouble with night vision. from that is the peripheral retina, sectioned off by areas called the midOPTIC NERVE
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periphery and far-periphery, where our rod cells take over. Damage to parts of our peripheral retinal can cause scotomas, or blind spots, in our peripheral visual field or even trouble with night vision.
OPTIC NERVE The optic nerve is the channel that attaches our eyes to our brains. The visual pathway is what we call the path that our vision travels from the outermost layer of the eye to the brain. The nerve is the second cranial nerve and any disturbance to it can cause vision problems or blindness. Disorders that cause pressure on the nerve, like glaucoma or idiopathic intracranial hypertension, can cause blindness if not adequately treated in time.
EXTRAOCULAR MUSCLES There are six extraocular muscles, and they all help control our eyes by moving up, down, side to side and around. Four recti muscles and two obliques are attached to each eye and work together to move the eyes in synch with one another.
Recti Muscles There are four different recti muscles on the top, bottom, and sides of each eye. Just as in everything else in ophthalmology, figuring out a mnemonic for the muscles can help when it comes to memorizing the EOMs. You can remember them as:
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Superior My boss above me is my superior. Inferior The guys below me are inferior to us. Medial In the middle, as in the middle of the face; nasal. Lateral Think lat-EAR-al because it is closest to the ear; temporal.
Oblique Muscles Just as the recti, there are superior and inferior (superior above, inferior below) but there are no side muscles. These muscles work a little differently than the recti, as well. These bad boys don’t just in and out or up and down they move the eye torsionally, which is just a fancy word to say that these muscles sort of twist the eye in different directions. Damage or restriction of any of the eye muscles can cause double vision. Often, prismatic lenses can help fuse images together if the eyes are misaligned, but surgery can be performed to realign the eyes in certain cases.
EXTERNAL EYE Eyes are protected by our lids. The lids are thin and the skin that lines them is the thinnest found on the body. They help keep our eyes from drying and close around the eye for protection of foreign bodies. Both upper and lower lids are lined with eyelashes which help catch large bits of debris. Under our lids and around the eye are meibomian glands that secrete oils and help the eye retain its moisture. Gland dysfunction can cause dry eyes and may need to be expressed if blockages recur.
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ORBITS Eyes are nestled into the part of the head called the orbits. Although the make up a part of the skull, the orbits themselves are made of seven different bones: the ethmoid, frontal, lacrimal, maxilla, palatine, sphenoid, and zygomatic bones. The orbital rim wraps around the eye in the front and the bones meet together in the back at the optic foramen, or apex. The orbit has four walls, superior, inferior, medial, and lateral, and the bones are joined together with sutures called articulations.
Conclusion Now we have a basic understanding of the eye as a whole. The eye is complex, so it is generally easier to refer to it by its components when talking about physiology and pathology. General eye doctors will see patients with problems concerning all of the parts of the eye, but note that there are subspecialties in ophthalmology pertaining to each specific segment.
Chapter 3
THE EXAM Comprehensive eyecare is extremely important. Unless you live near a major metropolitan area, you might not have access to different subspecialties. Optometrists and comprehensive ophthalmologists may have to don many hats to ensure that their patients receive the care that they need. Optoms act as the front line in routine eyecare or eye emergencies and general ophthalmologists will perform emergency lasers for glaucoma or retina patients from time to time, as well as the rare temporal artery biopsy. Comprehensive eyecare is not just refractions and rainbows. Now that we’ve seen a little about the various components of the eye, let’s focus on your role in the exam. As the first point of contact in a person’s eyecare, paying attention to their history is important. Before you can examine a patient, you have to find out what brings hem in and document their medical history and chief complaint.
CHIEF COMPLAINT & HISTORY Electronic medical record systems (and paper charts) are different means of entering information but all of the information required is the
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same across the board: allergies, medications, known diagnoses, previous surgeries, chief complaint (CC) and history of present illness (HPI). Most systems let you expand your CC into a note and, unless your doctor is completely against it, you should briefly enter some pertinent info there. Medicare, which makes the general rules that everyone follows in healthcare, requires certain data for different levels of care and reimbursement. Some practices require height and weight, some don’t. Some require blood pressure and pulse, others don’t unless performing a procedure. Find out what you need to have in your workup from management and make sure you hit those markers, otherwise, your practice can take a financial hit and they’ll come looking for the employee who is preventing the office from getting paid. Most systems allow for much more info, like family, social and sexual history. You should always fill out sections of the chart that your practice requires and anything extra that your physician may want. Fun fact (but not really fun): Having a chief complaint like “comprehensive eye exam” or “cataract evaluation” isn’t enough information for the insurance companies, so they can deny payment to your office. CC’s should always have some sort of modifier and it is best to use your patient’s own words (example: cataract evaluation; “my vision is getting cloudy”). Now, when I said “modifier”, I don’t mean the CPT code required for proper billing (more on that in the scribing section); I meant the term in the literal sense the different qualities that modify the patient’s chief complaint. These are kind of like the how, what, where, when and why of their main eye issue. Most exams with the eye doctor are routine, annual checks, so basic info is usually adequate for these patients and an HPI can look something like this: “Patient presents for an annual comprehensive eye exam; she states that her vision has slightly worsened at near since her last visit on MM/DD/YYYY. She denies flashes, floaters and eye pain at this time.”
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As a rule of thumb, include the last part to let your physician know that you asked about these symptoms and that the patient had declined them. This is referred to as a pertinent negative. If your patient wears glasses, take note of when their last pair was made and document the prescription in the proper area of the chart.
EXAMINATION Even if the patient doesn’t have any ocular complaints, ALWAYS remember to check their vision as if there is a new problem. Many people go to their routine eye exams with absolutely no complaints and are found to have color desaturation, a visual field defect, or other markers for a potentially serious problem. The basic exam is a culmination of objective and subjective tests and is roughly the same for most patients. The more you do it, the quicker you get at it but you absolutely need to do every step required every time. You do not want to mess up and check off PERRLA (which, by the way, stands for Pupils, Equal, Round, Reactive to Light and Accommodation) for people that have a known history of an afferent pupillary defect (APD) or click the button that says the patient has no confrontation field defect when they have had the same hemianopia for twelve years. There are three classifications of eye exams: routine, urgent, and emergent. Routine exams are the basic eye exam that patients have annually or every other year for gradual vision changes. Urgent exams are for more pressing matters like eye pain or intermittent double vision. Emergent eye exams are emergencies (penetrating wounds, sudden vision loss) and need to be seen right away in office or at a hospital. The American Academy of Ophthalmology outlines the eight steps of a comprehensive eye exam for physicians, much of which we technicians
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are responsible for performing on their behalf. These steps, called the 8 Point Eye Exam [1], include: 1. visual acuity 2. pupils 3. extraocular muscle function (EOMs) 4. intraocular pressures 5. confrontation field (CFs) 6. external 7. basic slit lamp exam, anterior and angle checks, etc. 8. dilated fundus exam Additionally, we are expected to read a patient’s current glasses prescription, check color vision with Ishihara plates, check for monocular suppression with stereopsis, and refract. Patients returning for a three or six-month intraocular pressure (IOP) check often don’t require refractions or dilation, so these workups run significantly quicker. Color Vision Color vision can be assessed in a few different ways. The Ishihara plates are a common way to check for deuteranopia (green looks reddish) and protanopia (red looks greenish). These plates contain small, colored dots that form a number or shape within a circle. Similarly, the Hardy-RandRittler (HRR) test is made of grey circles with hidden colored shapes within a square plate. HRR tests are better at detecting tritanopia, or blueyellow colorblindness. The Farnsworth D-15 test is made of small round tiles topped with different colors that patients have to arrange in rainbow order and can detect red-green color blindness, blue-yellow color blindness, and achromatopsia, or complete color blindness. Anomaloscopes are in-office machines that can detect and confirm the various types of color deficiencies.
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1. Visual Acuity Measuring the visual acuities, or VAs, of patients is one of the most defining aspects of an eye exam. Basic VAs check both eyes separately and together to find the best-corrected (cc) and uncorrected (sc) vision. As uncorrected vision is not as good as corrected, it’s best to check your patient’s acuities without glasses first if your practice prefers cc and sc acuities. People wearing contacts, however, could have their VAs checked with their lenses in first to save time. Hint: Stroke patients often have trouble calling out letters, not because they don’t see them correctly but because they have trouble verbalizing them. Using numbers or E’s usually works better. Acuities are measured using an eye chart that’s calibrated to simulate optical infinity, or 20 feet away. When we say “20/20”, the first 20 represents what the tested subject sees at the 20-foot mark and the second is where that vision compares to the sight or someone with “normal” vision. When someone has 20/50 vision, they clearly see at twenty feet what a person with normal vision can see at fifty. The most commonly used vision chart is the Snellen chart and consists of varying uniform letters. Other common charts include pictograms for young children and numbers or tumbling E’s (the capital letter “E” turned in different directions) for those with language barriers or cognitive issues.
1) Wrong. Figure 4. How to hold an occlude.
2) Wrong.
3) Correct.
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To check acuities, first check vision in each eye individually, then bilaterally. If you have a wall chart or projector that can’t randomize letters, check the acuity in the worse eye first to reduce the risk memorizing any of the chart. Otherwise, start with the right eye. Most paper and electronic records list the right eye before the left and this will just make the exam flow better. The 20/40 line is a good starting line to begin with, but if your patient can’t quite make it out, start larger until they can read the letters. Decrease the size of the letters until they can no longer read them and document your findings. To document, it’s best to write the last line read, minus any missed letters or plus any additional letters from the next line better. For example, if a person read all of the 20/30 line and saw two letters from the 20/25 line vision should be documented as 20/30 +2; someone who read more than half but not quite the entire 20/40 line would read as 20/40 -1. Visual acuity assessment is generally done at every eye exam (much to such patients’ protests). The only reason for a technician to not perform a VA is if there is a pressing medical emergency like a globe rupture or chemical burn. For incidents of chemical exposure, you must have the patient irrigate the eye with water for 15 minutes before all else. In instances where an eye cannot read better than 20/30, you should check the acuity again with a pinhole. Pinholes funnel light to the specific part of the macula that we use to see and, in effect, act as glasses do when they bend light to the same point. The result is the patient may see better, hinting that they probably have a refractive error. It’s normal for people with severe macular or retinal problems to not have any benefit from the pinhole, as we are limiting what they can see to the area of their eye that has been damaged. If checking VAs with a patient with latent nystagmus, occluding an eye may break fusion and cause the fast phase. If this happens, break out a frosted occluder to use after fusion has been restored.
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After pinholing, check the opposite eye in the same fashion. Once you have the acuities for each eye, check both at the same time, skipping the pinhole step. People tend to see better with both eyes open – sometimes even by a line or two – but patients with nystagmus, or involuntary and often rapid eye movements, often have very poor VAs with their eyes individually. This is because their eyes move and work together, giving them a pretty big monocular disadvantage.
2. Pupils If eyes are the window to the soul, then the pupil is the window to that window. Controlled by the surrounding iris, the pupil grows and shrinks to filter the amount of light that enters the eye. Generally speaking, the pupils work together and are about the same size, although 20% of normal individuals may have unequal pupil size. Sometimes change in size of the pupils between the two eyes is caused by an underlying neurological problem.
Relative Afferent Pupillary Defects When light strikes the pupil, the circular muscles of the iris contract, causing pupil constriction. When one pupil constricts, the fellow eye does the same this is called the consensual light reflex. When the light is taken away, both pupils enlarge again. Testing pupillary reflexes requires the swing light test. For the test, we use a light source, like a penlight or transilluminator, that we swing back and forth from one eye to the other. To record the pupil’s size in low light, shine the light at your patient’s cheeks so that you can see the eyes, but not so much that you construct them. Next, shine the light directly toward each pupil, noting the constricted pupil’s size. Swinging the light back and forth between eyes and look for constriction in each one, followed by consensual constriction by looking for a reaction in the unlit pupil.
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Pupils that have no direct or indirect reactions are called non-reactive pupils, for obvious reasons. A pupil that constricts consensually but enlarges under direct light has a relative afferent pupillary defect (RAPD, also known as Marcus Gunn pupil) and requires the immediate attention of a doctor. Sometimes the pupils of younger patients flicker during the swing light test. This slight “hiccup” in size change is called hippus and can make it look like a person has an APD when they do not. Check carefully and if you are still not 100% sure, ask a doctor to check as well.
Anisocoria As mentioned earlier, both of a person’s pupils are roughly the same size. When there is a difference in sizes, the person has anisocoria. Some people are born this way (congenital anisocoria) but some are caused by brain injuries, Horner’s syndrome, migraines, concussions or meningiomas. Pupillary defects can be acquired through trauma, asymmetric glaucoma, optic nerve disorders or even tumors. If you spot an APD or even a hippus, alert your doctor prior to giving your patient any eye drops. Just because they have had a normal reflex when they were last seen by their retina doctor 4 weeks ago doesn’t mean that they haven’t since developed a problem.
3. Extraocular Muscles Extraocular motility, or the movement of the muscles that surround the eye, is a major contributing factor to vision. The dysfunction of one or more muscles can be a symptom of a bigger underlying problem within the brain. In a later chapter, we’ll delve into the extraocular muscles (EOMs) more, but we’ll focus on just testing them for defects for now. For EOMs, it is important to have your patient fixated toward either your finger, light, or colorful object (if working with children a toy works). Distracted patients tend to look around, have choppy eye movements or try to guess where your fixation point will move next, all of which can result in unreliable findings. As tempting as it may be, do not rush through testing
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if your patient is having trouble following directions you risk missing a potentially serious problem.
Versions and Vergences These two terms sound a lot alike but mean two different things. A version is when both eyes work together to move in the same direction, like both eyes pointing up or to the left. Vergences are when the eyes work together but in the opposite direction, like converging to read at near. Methods for checking for versions and vergences is a deeply personal and often debated. You can ask any tech or physician about EOMs and you will most likely get a different set of instructions every time. Some make the letter H, X or O shape with their fixation object and others make a combination of those that look like the Under Armor brand logo. Testers may prefer to make a box shape with a vertical and horizontal line cutting through the center. Many people like to use the penlight or transilluminator with their finger over the tip and plenty more skip the middleman and just use their fingers. Patients often use the word “lazy eye” to mean one of their eyes has a misalignment. Really, the term means they have amblyopia, or one eye that has reduced vision without any particular cause. This often stems from childhood and can be treated with glasses if caught early enough. Make sure to verify what your patient means if they use this phrase during your eye exam. Again, there is an infinite number of variations to check eye movements, but it boils down to having your patient follow, focusing on whatever you’re moving in front of them. Move your fixation point up and down the center of their vision and then side to side to check their vertical and horizontal movements. Make an H shape that starts at the top right, moving downward. Cross over in the center and test from left upper and back down. Lastly, go back to the center point and move in toward the patient’s nose. Doing this will help you check the versions of all nine
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cardinal gazes, ensuring that the eyes are moving together as a team or yoking. The final bit checks the vergence of the eyes at near. When taking your history, it is good practice to ask our patients if they have blurred vision, flashes, floaters, eye pain or diplopia. If they report double vision, pay special attention to their extraocular movements. If everything appears fine, it’s time to move on to the cover/uncover test.
4. Cover/Uncover Patients with constant binocular diplopia occasionally have an ocular misalignment that you can see without further testing. But, even if there is no obvious eye turn, people can still have intermittent or constant double vision [2]. Double vision is caused by disorders of the extraocular muscles caused by either tropias or phorias, whereas tropias are always present and phorias only present when binocular viewing is broken. To test for tropias and phorias, you’ll have to perform cover/uncover tests. Have your patient sit up straight and focus on a target, such as your nose or a letter written on the back of a business card. Using an occluder, cover your patient’s right eye for a second and then uncover it. Focus on the uncovered eye and see if it moves or shifts at all. Check this way several times, switch to the other eye and repeat. Movement in this phase of the test means your patient has a heterotropia. If there is no movement, you can move onto the next part. For the next phase, do exactly what you just did for the first step, but this time look at the eye that you are occluding as you are uncovering it. Repeat with the opposite eye. For this test, if your patient’s uncovered eye shifts outward (temporally), they have an esotropia; inward (nasally), they have exotropia; upward would mean hypotropia and if the eye shifts down, it’s hypertropia. Finally, we have the alternate cover test to help detect phorias. Start by occluding one eye for a few seconds and then swiftly switch back and forth between both eyes. Observe the eye that you are occluding to look for movements you can do this by keeping track of the same eye during a
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few swings and then do the same for the other. Any shifting here would be caused by a phoria and follows the same deviation pattern as it does for tropias: temporal is eso-, nasal is exo-, up is hypo- and down is hyper-.
5. & 6. External and Slit Lamp Exam The slit lamp, or biomicroscope, is a gargantuan piece of the eye exam. Doctors and techs alike use the slit lamp for several reasons like external and fundus exams, intraocular pressure checks and foreign body removal. What your practice wants you to perform and wants you to never even think of doing may look completely different than other offices, so always check with your doctor first to see what is in your scope. Prior to setting up, you may want to instill a numbing agent and fluorescein, unless you’re checking the corneal surface. Of course, to use a slit lamp, you need to know your way around one. As most technicians are not responsible for examining the fundus, we will skip that phase, eliminating a good amount of the machine’s dials and knobs. As you could probably guess, the patient places their chin on the chin rest and their forehead against the headrest. If your patient is a little on the heavier side, especially toward the top, you may need to lower the slit lamp down and have the patient lean in or hunch a little to get into the lamp. Explain that it might not be the most comfortable position in the world but you’ll try to be as quick as possible. On the bar beside your patient’s face is a small notch or line this is a height guide that you should line up the eye to for your exam. Turn the joystick left or right to properly adjust this height and adjust your oculars for your own comfort. For your patient’s comfort (and so the patient isn’t leaning against the table and pushing it toward you) have them hold on to the handlebars below their face. Turn your lamp on with the center lamp set to 0°. With the light set to diffuse, sweep over each eye, observing the lids, lashes, sclera, and cornea, noting any findings along the way. Switch your light source to bar and angle your lamp at about 60° to check the depth of your patient’s anterior chamber angles. Hover the beam of light by the limbus
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but toward the iris. You should see two separate beams of light one superficially on the cornea and one internally on the iris. The shadow between the two beams tells you how deep the angle is and whether you are safe to give your patient dilating drops. Check both temporally and nasally for both eyes to make sure that your patient won’t go into angle closure if you dilate them.
Figure 5. Slit-lamp. 1) Oculars. Moves in and out for the distance between the user’s eyes. Turns to adjust clarity. 2) Adjust beam. Changes the size of the light beam. 3) Lamp bulb cover. Under this cover is the filter lever to change the light filter. 4) Forehead rest. Patients need to press their heads against this for best results. Sometimes seems like an impossible feat. 5) Tonometer. This is an optional attachment to the slit lamp. 6) Chinrest. The knob below the rest adjusts the chin height up and down. 7) Slit width control. Adjust mires when applanating. 8) Joystick. Moves up and down to adjust the microscope height.
The Van Herick technique, a set of guidelines for grading the anterior chamber depth based on the shadow between the two beams, states that when the gap is equal to or more than the width of the light bars, the patient has wide-open angles and it should be fine to give additional drops to. If
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Drops Eye drops are some of the often-used medications in ophthalmology. While some are reserved for office-use only, many are prescribed to treat inflammation, infections, glaucoma and other ailments. In the office, anesthetic drops like proparacaine and tetracaine are used for checking pressures, numbing the eye prior to dilating and in procedure prep. Dilating drops like tropicamide and phenylephrine work by enlarging the pupil and constricting blood vessels, respectively. Antiseptic drops like betadine are used in cleaning the eye and surrounding area before injections and surgeries. Following procedures or trauma, anti-inflammatory drops may be prescribed. Drugs like atropine work by dilating the pupil similarly to tropicamide but lasts about two weeks. Steroids like prednisolone also help prevent and reverse inflammation but can have unwanted side effects like increased IOP. Antibiotic drops are prescribed for bacterial infections and antifungals for fungi. Glaucoma drops have a variety of mechanisms and are prescribed based on the patient and his/her/their history. Some glaucoma drops work to increase the drainage of aqueous fluid while others decrease the production of aqueous. Certain glaucoma meds are beta-blockers and cannot be taken by everybody. If a patient is taking any drops, be sure to document the name, strength, and dosage during your workup. Even artificial tears and ointments. If your patient is putting it in their eyes, the doctor needs to know about it to help them see the full picture of the eye’s health. the shadow is half the thickness, angle closure is still unlikely. In the instance that the shadow is ¼ the thickness of the light or less, have your doctor perform gonioscopy and let them make the call on whether or not it is safe to give dilating drops. To cover yourself, document that the physician approved or declined dilation based on his or her gonio [5].
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7. Tonometry Circling back to the fourth step in the 8 Point Eye Exam, measurement of intraocular pressures (IOPs) is a vital part of the eye exam. When pressures are too low, that’s a bad sign and when they’re too high, well, that’s bad, too. The measurement of intraocular pressure is called tonometry and applanation with the Goldmann tonometer is the best way to check IOPs. Pressures measured this way are read in millimeters of mercury (mmHg) and healthy IOPs stand within the 10-22 mmHg range. Low intraocular pressures, or hypotony, is when a person has a pressure lower than 5 mmHg. Low pressures can occur after surgical procedures or by decreased aqueous and dehydration [6]. The more commonly occurring problem with IOPs is glaucoma, or the elevation of pressure in the eye. In most cases, a high IOP is anything above 22 mmHg, but this is not always the case. Glaucoma can be naturally occurring if the eye does not filter out aqueous as more is produced but it can also be caused by ocular trauma. Primary open-angle glaucoma (POAG) can affect anybody, but the risk of developing it is higher in those of African descent and people with a family history of it. If a person presents with high pressures during their exam, a physician may give (or have you give) drops at that time to lower the pressures. After about twenty minutes, you’ll have to recheck your patient’s pressures to make sure they are normalizing. If the IOPs aren’t decreasing, or if the doctor finds it to be the right call, they may have to perform an in-office laser procedure to help bring the numbers down. This is why it is crucial to properly document accurate pressures. Everyone has a different rhythm for how they test patients, and in time, you’ll find the best pattern for you, but it is always best to perform the slit lamp exam prior to checking IOPs. If your patient has a pizza-shaped gash on their cornea from nicking themselves with their artificial nails, you’re most likely not going to want to applanate them. If there aren’t any alarming findings under the slit lamp and the patient has been given a numbing agent and fluorescein, place their chin on the chin rest with their forehead against the headrest. Adjusting the height so that their eye is lined
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up with the notch on the bar that stands beside their face, flip the light source on and from white to cobalt blue (the darker, royal blue, not the aqua-colored cyan filter). A Note on Optometric Assisting Although this book deals with ophthalmology and its various subspecialties, optometric techs can learn a bunch about eyes and eyecare that will definitely come in handy throughout your career. In general, the patient workup for an optometric patient is pretty simple. The main difference between optometric and ophthalmic teching is that you won’t have to refract (that’s the optom’s job) and you might not have to applanate to check pressures – optometrists generally use non-contact tonometry, AKA the puff of air, for this. Set your dial to 10 (mmHg) on the Goldmann drum and carefully line the applanation prism tip up to your patient’s cornea, fully lift off of it to re-center it if needed (you don’t want to drag the tip against their eye and scratch it). You’ll want to get as close to the cornea as possible before looking through the lamp. Personally, I like to use only one side of the oculars so I can easily come in and out for any readjusting of the knobs, but in time you will find what you are most comfortable doing.
Too far apart
Too close together
Just right
Figure 5. Mires alignment on the Goldmann applanator.
Once you touch the surface of the eye, you will see a broken neon green circle through the eyepiece. These half-circles are called mires. If your mires are either too low or too high, pull back and realign them so that they appear centered in the slit lamp. Turn the dial on the Goldmann
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applanator until the insides of the two half-circles just touch each other. Mires that are too thick from excess fluorescein will cause a false high reading and mires that are too thin from not enough dye and give a false low reading. Note the number on the drum for the pressure of that eye and repeat this process on the other one. Applanation is the most accurate way of detected intraocular pressures, but it is not the only way. The Perkins handheld was a miniature Goldmann, prisms and all, that you could hold in your hand. If your patient is bed-bound or in a wheelchair and the slit lamp cannot meet them, the Tonopen or AccuPen is an easy fix. This handheld tonometer reads the pressures ten times before giving you the most accurate reading (three times if using the Tonopen XL). Using the either of these handheld guys requires covering the tip with little disposable latex sheaths that are discarded after each patient but eliminates the usage of fluorescein, which is great because, at time of this writing, there has been an on and off again shortage of the dye for a few years. Tonopens and AccuPens are fast and easy to use and are generally accurate, but their readings may not be too reliable if the patient’s pressures are outside of that 10 to 22 mmHg goldilocks zone. Patients holding their breath or wearing tight collars can have false high readings. So can eyelid squeezing. Relaxed patients have the most accurate readings, but relaxing during a pressure check is often easier said than done. Similarly, the iCare tonometer is a handheld tonometer, but this one even eliminates the usage of the anesthetic drop, which can cause corneal toxicity if overused. This instrument takes accurate readings by triggering a small, rounded tip pin that quickly moves back and forth, bouncing off the corneal surface. The pressure check is so quick and light that most patients do not even feel the tip. The pins are trashed after each use, which drives up the cost of using it, but the machine is great (especially for dry eye and cornea patients). Since the prism tip used during applanation is
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3.06 mm in diameter, using the iCare is generally better for patients with cornea problems. There are many more tonometers coming down the pipeline, like the Diaton tonometer that reads pressures through the eyelid, as well as older ones like the prehistoric monster we’ve all studied to pass the COA, the Schiotz. Never used a Schiotz? That’s because it’s not the 1650’s anymore. Last and definitely not least is the non-contact tonometer also known as the puff of air machine. Earlier models of this machine sound like an airsoft shot and blast an uncomfortable puff into the eye. What’s worse is that the patient would have to sit through the test again if they became scared and flinched or if the machine misfired. Handheld models like the Keeler’s noncontact didn’t give the patient or the administering tech any warning as to when it was going to go off. Despicable. Luckily, updated models don’t sound as scary and are more reliable, but not as much as their contact cousins. The non-contact tonometer is probably the most hated part of a routine eye exam and is the reason why some patients get nervous when being tested with an autorefractor, topographer or OCT. Those things can be traumatizing. As with everything else, use discretion when checking pressures. Referring back to the girl who scratched a chunk of her cornea off with her artificial nails, you probably shouldn’t applanate them (check with your doctor to see if it’s okay to use a handheld tonometer in situations like this, as they check a much smaller area of the eye). Every doctor and clinic has a different protocol, but almost every one of them will want IOPs checked no matter what, but it is always best to have a doctor look at your patient if you have concerns. This is someone’s eye we’re talking about; if it were my eye, I’d appreciate some caution and I’m sure you would, too. Because we give instill them so frequently, it can be easy to forget that eye drops are a medication. Just like all other drugs, the drops we give (even the numbing drops) can cause serious adverse reactions if the patient is allergic to them. In the event that a patient has an allergic reaction or faints, call for the doctor and help immediately.
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Conclusion Eyecare is completely different from the rest of health care. The eyes are their own system and working with them takes skill, knowledge, and a strong stomach. The 8 Point Eye Exam is a basic outline of how the patient encounter progresses and techs are often responsible for most of it. VAs, pupils, EOMs, IOPs, CFs, external exams and slit lamp exams may be within your scope on the job and each task is important in checking the eye’s health. Refracting patients isn’t included in the 8 Point Exam but is vital for vision. Glaucoma, trauma and patient anatomy can all affect how a person sees and it is our job to document both their history and our findings.
Chapter 4
REFRACTION Refracting can be one of the longest parts of the eye exam, especially if your patient flip-flops through their answers. To avoid getting frustrated, think of refracting like a game where you need to find the best set of lens options for your patient. Malingerers are just a tricky part. You may have to check each choice several times, but the goal is to get the best possible manifest refraction. Be thorough and double or triple-check a refraction if need be. Doing so can virtually guarantee that your patient will be happy with their new ophthalmic prescription and won’t be back in two weeks for a glasses check. Hyperopic eyes are shorter and need magnification to have light reach the back the eye. Myopic eyes are longer and need a minimizing lens to project the image on the retina. Eyeglass and contact lens prescriptions consist of four main parts (excluding prism, more on that in the Optics section) and are measured using phoropters and trial lenses. Scripts are written in diopters in quarter increments and are written like +2.25 or -0.75. The first thing that an ophthalmic prescription corrects for is distance, both near and far. This section of the Rx is referred to as “sphere”. Folks with myopia, or trouble
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seeing far away, need negative sphere for correction. Conversely, those who require assistance see up-close, or those with hyperopia, need plus sphere. This is because minus, concave lenses shrink images to bring images in focus for myopes who have longer than usual eyes and plus, convex lenses magnify images for hyperopes with their shorter eyes. A quick way to remember this is to think that smaller eyes need to be magnified. The second and third parts to a glasses script are the cylindrical correction and the axis that it sits on. Cyl and axis correct for astigmatism, which just means that the cornea is not as spherical as it could be, causing distorted vision. In optometry and optics, minus cylinder is used for refractions while plus cyl is used in ophthalmology.
(a)
(b)
Figure 6. Astigmatism. (a) A spherical cornea. (b) A cornea with astigmatism. Note: the cornea is more football shaped than baseball shaped.
STARTING POINT Before refracting, it is best to set the phoropter with either a previous glasses prescription, a previous manifest script from the patient’s chart, an autorefraction or findings from manual retinoscopy. They may not be perfect but autorefractors (AR) tend to be very close to what the patient needs for correction so they make fantastic starting points. To use the AR, just instruct your patient to place their chin in the chin rest and gaze at the focal point inside. This is sometimes a star, barn or hot air balloon take the test yourself to see what image your patient needs to focus on when you have the time. Each machine is different but most have a button to
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raise or lower the chin rest and a joystick or rollerball to find the patient’s eye for the perfect fixation point. Newer model machines will automatically measure the script but some models will have you click a button to begin. The machine does the rest for you. Older models will have you glide over to the other eye, but most won’t even make you do that. Once the eyes have both been tested, a printout with the best-estimated prescription spits out for you to copy into the phoropter. As a bonus, you can set the AR up to feed you the K readings as well, which is perfect for contact lens fittings.
RETINOSCOPY In the 21st century, most of us are fortunate enough to work for an office that has some sort of autorefractor. However, some techs who have to travel to sites without one or those who need to refract people who cannot necessarily work themselves into the machine (babies, those with cognitive disabilities, etc.) may need to check the eyes with a method called streaking or retinoscopy. Retinoscopy, which is something that you’ll need to study should you take the COA, COT, or COMT exams, requires the use of a retinoscope, loose lenses, and an eyeball. Set the scope to a vertical bar and sweep the light over the eye, back and forth, a little over two feet (26 inches) from your patient. The goal here is to get your beam to look like a fat beam that illuminates the retina, making a red reflex. To do this, you have to add or subtract lens power to change the beam’s thickness. If the light is moving in the same direction that you are swinging it, you need more plus, if the light swishes in the opposite direction, you need more minus. If the beam of light does not appear entirely vertical, or you can’t manage to get the beam to illuminate the eye properly. You will have to check the eye for astigmatic correction. Hold a cylinder lens up to the eye, turning it until your line matches vertically to your scope. Increase your cyl power to widen the beam.
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Since we only have so many hands, it’s a good idea to streak your patient with a phoropter or in a trial frame when possible. In certain cases, especially with infants, neither of those options is viable so holding loose trial lenses up to the eye will yield the best results. Whichever the case, it’s important to keep your arm completely straight the entire time to steady the light and maintain your distance.
Refinement When you find a baseline prescription to start manifesting with, subtract +1.50 from your spherical value. If your reach isn’t that long and you’re more like twenty inches away, subtract a full two diopters. Retinoscopy is great for checking refractions after you’ve manifested by holding your working distance (+1.50 or +2.00) lens in front of them and streaking to see if they’ve been completely neutralized. Once you have a starting point loaded into the phoropter, have your patient sit upright and bring the machine to their face. You can use the forehead control dial (center knob) to adjust the forehead depth, adjust the pupillary distance with the PD dial (top right dial) and balance both sides the horizontal leveling knob directly below it. Once you have both eyes centered in the lenses, occlude the left eye using the aperture control so you can begin refracting the right. Explain that you will be showing him or her several lens choices; not all of them will be clear, but you need them to tell you which lens of the two choices is better. Have them read the 20/40 line or two lines above their best acuity. If they can read every letter clearly, you can begin refracting, otherwise, keep going up a line until it is clear. The largest dial on either side of the phoropter is the spherical disk. Click the wheel down one notch to add +0.25 sphere to your staring Rx. Ask the patient “Which is better- choice 1…”, then click back up to the original and finish “…or choice 2?”. If they like the additional plus power, continue this process in the same direction in +0.25 increments until they stop. For patients that like the
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original starting point correction better, start clicking the sphere wheel upward in single -0.25 increments. Continue in that direction if they prefer more minus until they stop, but be careful people love minus and will often want more than they need. After about -0.50 or so, you’ll want to assess if they truly need the minus or not. Try adding some plus again and carefully offer minus little by little to see if it’s actually needed or the patient just wants it. Patients who prefer the original sphere or have found the corrected sphere that they like can move onto the axis part of the refraction.
Figure 7. Phoropter. 1) Sphere wheel. 2) Jackson cross cylinder. 3) Auxiliary lens knob. When the wheel around the knob turns, the sphere wheel jumps three diopters. 4) Leveling and PD knobs. 5) Level. 6) Cylinder power and axis knobs. 7) Cylinder axis indicator.
JACKSON CROSS CYLINDER To check the axis of your patient’s astigmatism correction, we use what’s called the Jackson Cross Cylinder. Flip the Jackson Cross down, so that the lens is open over your patient’s eye. You will want the white and red dots to straddle the axis that you set, so the dots are 45° away from the
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axis on either side. Have them read the line of letters and ask “Which is better, 1 or 2…” while flipping the small round wheels on the Jackson Cross. When refracting in plus cylinder, you always want to “chase” the white dots. Turn the axis knob 15° toward the white dot on the choice that the patient selected as the better option. Flip and repeat, lowering the increment of change down each time you go back and forth (10°, 5°, 3°, 1°) [3]. Once you’ve found the axis, turn the outermost dial on the Jackson Cross so the dots now line up with the “P” inscribed on the wheel (the “P” represents “power”). Flip the lenses again, asking which is better, 1 or 2, 3 or 4 and so on. When patients prefer the choice where the “P” is next to a white dot, increase the cylinder power. Patients that prefer the red dot beside the “P” want less cyl, so decrease the power. Continue flipping up or downward until your patient thinks the two choices look the same, they prefer the other direction or they get back down to 0.00 cylinder. Once you finish the right eye, repeat the steps over for the left. Open both eyes back up after you’ve finished and have them read the chart binocularly. Make sure that they can see the chart clearly (or as clear as possible) and ask them if they experience any horizontal, vertical or diagonal double vision. If they don’t, you’re good. If they do, note this in the chart and fill your doctor in to see if they’d like to evaluate them before moving on to the next step.
DUOCHROME You have reached a manifest refraction with clarity and no diplopia. Success. Next, we just verify that there isn’t too much plus or minus to the prescription. The duochrome test consists of letters on a screen or chart that is split vertically down the middle, one side green and one side red. Basically, the goal here is to get the letters on both sides to appear equal in boldness. This test can be performed with one eye or both open. Ask your patent “Do the letters on either side look bolder or blacker?”. People who choose the red side can have plus taken away until the sides look even, but more importantly, you can add plus power for those who say the green side
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looks bolder to create balance and ensure you aren’t over minusing your patient. Low Vision Certain patients are unable to correct past 20/40 or have such limited tunnel vision that everyday tasks can be extremely difficult. Low vision aids can sometimes help those with limited vision. To better figure out what a low vision patient needs for their best sight, they may need to be streaked (retinoscopy), as an autorefractor might not be able to get a good reading from them. Obviously, patients that are NLP won’t need either and a refraction won’t be of any help, but always exhaust every option in an attempt to get any sort of improvement. Many low vision patients find certain devices, like magnifiers, telescopes, and loupes to be beneficial. Part of the job of a low vision tech is explaining what these devices do and how to use them properly.
PRESBYOPIA When you finalize your prescription, you can throw the lenses in a trial frame and have them wear it to make sure they are comfortable looking around with it, but this is not necessary. What is, however, is checking for a bifocal segment or “add” power with people who have complaints of trouble seeing up-close and anyone over 45 years of age. That’s because as eyes age, they accommodate less, making focusing up-close impossible. This is called presbyopia. There are a couple of ways to test exactly how much added power a presbyope needs and it can be done using either a phoropter or the trial frame. Add powers, like sphere and cylinder, work in quarter diopters, but usually range from +1.50 to +3.00. The add segment is just extra magnification that is literally added to their distance prescription. Traditionally, people in their mid to late 40’s only need +/- +1.50 added help and that number increases as we age. Table 1 illustrates the common ranges for additional near power based on patient age [4].
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Keli B. O’Connor Table 1. Common ranges for additional near power based on patient age
Patient Age 45-47 48-49 50-51 52-54 55-59 60-62 63+
Near Power +1.00 +1.25 +1.50 +1.75 +2.00 +2.25 +2.50
Now, the above table is a great starting point for finding the required power, but you cannot rely on it alone. In your phoropter, update the sphere to reflect their distance vision sphere plus a starting add power. For example, a person needing a +2.50 add with a -4.00 script would come down to -1.50 and somebody needing a +2.25 add when their script is already +1.75 would come up to +4.00. Have your patient hold or place a reading card 14-16 inches away from their face. Phoropters that have the bar attachment can hold a near card for you. Instruct your patient to read the smallest line that they can make out and have them focus on that line while you ask them which of the two lens choices that you’re presenting to them looks better. Click the sphere disk up can down, just as you did when checking the distance vision until you and your patient find the lens that looks clearest. Subtract the starting distance power and you have your add. When you find the add they like best, ask them to read down to the smallest line and record what they read.
Alternatively, you can check for add powers using a trial frame. This method is great because you can have your patient hold the near card at a distance that they are most comfortable reading while wearing a script that will potentially be in a future pair of glasses. With their prescription plus
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the tentative add power in the frame, hold +0.25 loose lenses over their eyes and ask which is better, with or without the extra lenses. Continue to increase the add power by quarter diopter increments until you’ve hit the clearest point for near vision. Add powers are usually the same bilaterally and it’s extremely uncommon to prescribe two different adds for near. Computer glasses or intermediate distance power can be found by halving the near add and applying that half to the distance script. It should be noted that refracting children and adults under the age of 40 should be done with and without cycloplegic drops. Younger adults and children have uncanny accommodation abilities and, because of this, undilated refractions might still be off. Drops are given so that the patient cannot accommodate, thus making the refraction more accurate. Children and young adults don’t typically need bifocals, but some people with certain retinal and optic nerve issues may. Don’t worry about testing for adds with anyone under 40 unless your doctor specifically tells you to or they have already been prescribed bifocals in the past.
DIFFICULT REFRACTIONS Some patients are, unfortunately, more difficult to refract than others. There are, however, different tricks to help narrow down their true manifest more precisely. You just need to be patient and get creative. During their refraction, some patients may only go for the higher number when you ask them 1 or 2, 3 or 4. To verify that they are just chasing the number and not the correction that they need, you can switch the numbers of the same lens options. For example, if you called the -0.25 lens choice 1 and -0.50 choice 2, you can change it up on the patient, calling -0.50 choice 3 and -0.25 choice 4. If they still choose the higher number instead of the option that they chose the last turn, they might just be flowing the pattern. A good way to work around this is by calling the lens choices by letters instead of numbers. Fogging your patient can also help when refracting younger, more accommodative patients. To fog, set your phoropter to your best-corrected
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manifest and add plus power slowly, instructing your patient to let you know when the line they are focusing on (20/40 is a good start) becomes too blurred to see. Once they hit that point, click you minus wheel back three times and you will have your best-correction without over-minusing. Patients with nystagmus require extra attention when refraction. Nystagmoid eyes work rhythmically together, so it is best to refract each eye individually as good as you can before refracting them with both lenses open. Instruct your patient to try to focus on what they are seeing with their right eye and try to refine the prescription again. Repeat on the left side and you may actually be able to refract them down to the 20/20 line.
Conclusion Refractions are a necessary part of the eye examination, whether the patient is interested in a new script for glasses or not. There are many steps in the test, and it is easy to get overwhelmed at first, but taking your time to carefully refract each patient is better than speeding through it and messing something up. Some patients will be more difficult to refract than others, but patience and diligence for everyone will go a long way.
Chapter 5
CATARACTS If you work in eyecare, you are bound to run into cataracts early on and often. Cataracts are one of the most common causes of diminished vision. They develop naturally as we age but can progress with medications, like steroids, or trauma. Common complaints with cataract patients include fogginess, dullness, and trouble with night driving or glare. Not only does the clouding of the natural lens decrease visual acuity, but vision can be worsened in brightly lit conditions. The opacity of the lens takes light that would normally help illuminate our surroundings and scatters it, causing glare and haloes which can be very bothersome. These opacities are also the reason that vision is decreased (imagine dirt deposits on an old window) and colors appear muted (like cloud coverage dulling the normally vibrant blue sky).
COMMON TYPES Of all the types of cataract, you are most likely to encounter three types in the office: nuclear sclerotic, cortical, and posterior subcapsular. Nuclear sclerosis (NS) is by far the most common and is the overall cloudiness that develops throughout the lens. Cortical cataracts, also called cortical
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spoking (CS), gets its name for the spokes and spikes of opacities that form along the lens’s cortex and point toward the center. Lastly, posterior subcapsular cataracts (PSC) are splotches of opacities under the lens capsule and inside the posterior cortical layer. Patients with any of these cataracts often require additional testing to determine the severity of their lens opacities and if surgical intervention is warranted.
SPECIAL TESTING First, patients should be glare tested (see Visual Acuities) with the Brightness Acuity Test (BAT). The BAT attachment hooks up to any handheld base and has a bowl-shaped opening that the patient places over an eye. With their other eye occluded, the patient reads from the eye chart at three different levels of brightness: one set to simulate indoor fluorescent bulbs, one to simulate being outside on a cloudy day, and one to simulate being outside on an especially sunny day. As cataracts cause trouble with glare, the patient’s vision is expected to worsen as the brightness goes up. Next, for certain patients or physician protocols, a corneal topographer maps the cornea of the pre-operative eye and finally, an IOL calculation will measure the depth and structure of the lens. Cataract patients require a very careful refraction as well as a history that includes all previous eye procedures, past ocular injuries and any previous or current steroid medication usage. Occasionally, a doctor may want to use a Potential Acuity Meter (PAM) to see if the patient’s potential acuity would improve after cataract surgery. This test, which hooks up to a slit lamp, projects a miniature eye chart onto the patient’s retina through any media opacities. The physician evaluates the patient and uses the information from all their testing to decide which artificial intraocular lens (IOL) to replace their old one with. People who’ve had cataract surgery can have several post-op checks throughout the first year, from one-day, one-week, one-month and
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three to six months after the procedure. The first-day exam is usually pretty simple and includes a visual acuity and pressure check – usually with a handheld tonometer – on the post-op eye only. The eye will still be dilated so there’s no need to check for a reaction or APD. At the one-week mark, check the vision, pupils, fields, and pressures, and at a month do the same and throw in a refraction, as the eye should be adjusted enough now to update glasses, if needed. Physicians all have different dilating schedules between the first- and sixth-month follow-ups, so give drops per your doctor’s schedule for these visits and when they are back on their regular annual schedule. Like tonometry, nuclear sclerotic cataracts are graded on a scale of 1+ to 4+, based on opacity. Cortical spoking and posterior subcapsular cataracts are graded on a scale of 1+ to 3+ based on area. Patients with traditional IOLs will need to use reading glasses for their up-close work, as their once adaptable lens was replaced with a rigid plastic one, rendering accommodation impossible. Those who elect to have monovision have one eye implanted with a lens for distance and the other for near. This is a great option for people who previously wore monovision contacts but may be too much for other people to adapt to. Multifocal IOLs are on the rise, but some people still need to use readers on occasion. When checking vision with or refracting patients with monovision or multifocal lenses, make sure to note these special IOLs, as these can make a difference with the dispensed spectacle or contact lens prescription. After cataract surgery, people with a replacement IOL have pseudophakia, (pseudo- meaning fake and -phakia meaning lens). If no lens is replaced, the patient has aphakia (no lens).
Conclusion Cataracts are extremely common, especially in older populations. The vision loss from lens opacification can be treated with surgery, where the
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natural lens is replaced by a plastic alternative. The new lens is not as accommodative as the old, so patients will likely need readers or progressive glasses postoperative, unless they elected to have monocular or multifocal IOLs implanted.
Chapter 6
GLAUCOMA Glaucoma is a condition that damages the optic nerve, causing peripheral vision loss. If left untreated, the field loss can slowly creep toward the area of central vision, resulting in permanent vision loss and blindness. To halt the progression of glaucomatous damage or optic atrophy in the back of the eye, it is important to test and treat the anterior chamber in the front. The most common form of glaucoma is open-angle, which refers to the angle of the anterior chamber. In this kind of glaucoma, patients tend to have a high intraocular pressure (IOP); this pressure can cause damage to the optic nerve, leading to visual field defects. Slow peripheral field loss can go undetected for years before it becomes problematic and by then it is too late. Early detection through screening perimetry and examination of the fundus is the best course of action in preventing vision loss from glaucoma. If undetected, the visual field loss can progress, until the person only has a small window of central vision in each eye or worse no vision at all. The first course of treatment of high pressures is usually drops. Some drops work to help flush out excess aqueous while others work toward decreasing production of it. If drops aren’t cutting it, physicians may decide to treat with laser.
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Narrow-angle glaucoma is when the anterior chamber angles are narrow and don’t adequately filter out aqueous fluid. This is disastrous when a person with narrow angles is dilated, as the angles are narrowed even further and can close completely. Acute angle closure is ugly. The patient can suffer from terrible eye pain, severe headaches, nausea with vomiting, and worsening blurred vision. People with anatomical narrow angles are at risk for closure, even if they aren’t being dilated so their ophthalmologists may decide to perform a Laser Peripheral Iridotomy (LPI) to create small holes in the iris to increase outflow. Though certain ethnicities (those of Asian descent) are genetically predisposed to anatomical narrow angles, anyone can have them, especially if they are high hyperopes (super farsighted) or have had ocular trauma. Checking eye pressures is an important part of a glaucoma check, no matter the type. Typically, applanation with the Goldman tonometer is best, but other forms of tonometry may be used for special cases, depending on office protocols. To ensure that the IOPs are not artificially high, patients should be instructed to breathe normally and the thickness of their corneas could be gauged. Corneal thickness is measured with an instrument called a pachymeter, which are handheld devices you lightly touch the center of the patient’s cornea with after you’ve instilled numbing drops to get an averaged series of readings. This test is important from both a corneal and glaucoma standpoint. Thicker corneas, or those greater than 565µm, can yield an artificially high IOP and thin ones, less than 535µm, may disguise a truly high IOP as normal. Corneal thickness can also play a part in how a surgeon goes about performing a corneal procedure, which we will discuss more about in the next section.
Conclusion Glaucoma is one of the leading causes of permanent vision loss worldwide. High intraocular pressures are a general marker for the openangle variety, but narrow-angle and the other types have different
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mechanisms that need to be monitored. Drops are the first step in lowering pressures, but surgery is sometimes needed for emergencies and with aqueous drainage issues.
SECTION II SUBSPECIALTIES
Chapter 7
CORNEA The cornea subspecialty is a fascinating and integral facet of eyecare. The cornea accounts for about 65-75% of our vision, which is roughly 43 diopters in total [7]. But this subspecialty is more than just scratches. Cornea specialists perform cataract surgeries (see Cataracts in Chapter 5) and keratoplasties (corneal transplants), treat keratoconus and prescribe corrective lenses.
KERATOCONUS Normally, corneas are rounded and spherical, like a little dome stuck onto the front of the eyeball. Some corneas protrude outward more, giving them a more cone-like appearance. This is called keratoconus. The term is easy enough to remember, because “kerato” means cornea and “conus” is, naturally, a cone. When correcting refractive error, sphere generally corrects for the length of the actual eye and cylinder corrects for astigmatism and the shape of the cornea. People with keratoconus tend to have much higher than normal cyl. Cylinder over +3.00 is considered high and keratoconus patients can need correction from +3.00 to +6.00, possibly more.
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Phoropters can refract up to +6.00 cylinder but, in the event that you need to refract someone with more than that, a cylinder extender can be attached. Keratoconus patients often require additional testing, like keratometry, or K readings, and corneal topography (see Topography in Diagnostics). These tests help physicians determine whether glasses, contact lenses or surgery would be the best treatment. Rigid gas permeable lenses (RGPs) are commonly used to treat people with high astigmatism or keratoconus. RGPs are harder than readily available soft lenses and help shape the cornea when tears fill the space between the eye and the lens. This, coupled with the suction of the lens, help create a rounder ocular surface. Though RGPs do offer some stock lenses, patients with steep corneas or other corneal pathologies typically require custom made lenses.
Keratometry You might not have a manual keratometer in every practice, but they are fantastic when it comes to fitting contact lenses – especially RGP lenses – and measuring astigmatism. The keratometer readings, or K’s for short, help prescribers determine what size and steepness a person needs for their contacts and can help physicians determine the best course of treatment for other corneal issues. On the vertical and horizontal drums, there are little notches. These markings represent your diopter power – the horizontal for the horizontal meridian and the vertical for the vertical meridian. On the axis scale, the horizontal reading white line at or around 180° (plus or minus 20°) and the vertical is on or at 90°, plus or minus. Axes are always 90° apart. For example, a K reading will look similar to this: 42.00 @ 180/43.50 @ 90 In the above reading, the first set of numbers before the slash represents the horizontal meridian reading, where the 42.00 is the diopter
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power and 180 is the degree of axis. The second set after the slash is the same thing but for the vertical meridian.
Figure 8. Keratometer. 1) Patient chinrest. 2) Headrest. Not Comfortable. 3) Axis drum. 4) User eyepiece. 5) Measurement drum. 6) Focusing knob. 7) Chinrest knob. 8) Keratometer height knob.
To use a manual keratometer, adjust the eyepiece first by focusing in the center of your view [8]. Do this by turning the dial counter-clockwise all the way, then slowly begin to turn clockwise until it comes into focus. Have your patient put their chin in the chinrest, forehead forward against the bar and adjust their height as needed so that their eye lines up with the alignment marker on the side. Once the height is properly adjusted, you should see a white ring on the center of the patient’s cornea. If the ring is not centered, move your patient’s head around until the circle is dead center. When you look through the eyepiece, your plus sign should be centered. You should also see three circles through the eyepiece, all of which have plus and minus signs straddling them. Turn your horizontal dial until the plus sign of the center (focusing) circle becomes one with the plus sign beside it. This is how you find your horizontal reading. Next, turn your vertical dial so that your minus sign from the center circle is superimposed on the one above it. This is your vertical reading. All the while, you’ll need to torsionally
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move the machine to find the axis. Once you have all of your lines superimposed and your axis is set, you have your reading.
REFRACTIVE SURGERIES First, there were glasses to help people see better. Hundreds of years later, hard contact lenses were developed to improve vision but in a way that made it look like you didn’t need glasses. Eventually, soft lenses hit the market to make the use of CLs more comfortable. Lastly, doctors figured out a way to surgically correct vision. Refractive surgery is a blanket term for several different procedures that alter corneal shape or involve placing a lens in the eye so that vision improves, often to the point where glasses are no longer needed after the procedure. While bladeless laser options like LASIK and PRK are available, not all patients are candidates for this type of procedure. Patients who aren’t lucky enough to have mild to moderate myopia have to stick to the slightly more invasive type, like radial keratotomies (RK) and phakic IOLs, if eligible at all. Surgeons have been performing RKs since the ‘80s and the technology has made leaps and bounds since then, but these surgeries don’t come without their risks and side effects. Many people who have visionenhancing surgery will have a seamless procedure with 20/20 vision afterward but not everyone can be corrected to that point. High myopes might only get corrected to 20/25 or 20/30 in one or both eyes, which they may find extremely disappointing as they just spent thousands of dollars on surgery to “fix” their vision. When people spend that kind of money on an elective procedure, they tend to expect perfection, noting that if they knew they would still need glasses, they wouldn’t have signed up in the first place. Patients need to know ahead of time that not only is there a chance that their vision will not be fully corrected to 20/20, but that their vision can regress over time. Also, anyone signing up for refractive surgery should know that they will need to wear reading glasses (or bifocals) at some point and that it’ll probably be sooner than if they didn’t have the
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surgery. The surgeon will be going through all of the risks involved when he/she consents the patient for the surgery, but it is important to be well versed on what to expect and what could go wrong in case the patient asks you about it.
CORNEAL INJURIES Injuries are a common occurrence when working in a cornea subspecialty and are not unusual for optometrists or general ophthalmologists. The cornea is extremely sensitive to touch and an even minor scratch can be very painful.
Corneal Foreign Bodies The cornea is a sensitive structure of the eye. Luckily, we have lids to cover them and keep our eyes safe from dirt and debris but every once in a while, something manages to get in there. Foreign bodies (FB), whether dust, sand, glass, metal, or anything else, can irritate the eye and cause serious damage to the cornea. If the FB cannot be removed through irrigation (running water or artificial tears over the eye), it can be removed in the office in most cases. Once the eye is numb, the doctor may use a sterile swab or forceps to pick the foreign body off and drops are generally prescribed afterward to prevent infection and help the cornea heal, especially if it was abraded. In the case that the foreign body was metallic, the eye may develop what’s called a rust ring. This reddish-orange or brown circle of discoloration left on the surface of the eye after the metal FB has been removed also needs to be removed. Jewelers’ forceps may work for rust ring removal but often times a small, battery-powered rotary brush called an Alger brush is used instead.
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Abrasions A scratch or corneal abrasion can be extremely irritating. Patients might complain of foreign body sensation, redness and tearing or may say they have trouble keeping their eye open. Abrasions are the shallowest of injuries and can be seen by applying fluorescein and looking at the eye under the cobalt filter in the slit lamp. The fluorescein acts kind of like a highlighter and illuminates the scratch. Check with your doctor on whether or not you should check an IOP for your abrasion patient if you do, you may be better off using a handheld tonometer to avoid touching the scratch.
Lacerations Thicker, deeper cuts to the cornea are called lacerations. Patients with these often complain of the same things as those with abrasions and though you can use the above fluorescein trick, you can sometimes see lacerations with the naked eye. Lacerations can be either partial or full-thickness and may not heal as well as abrasions if left unchecked. The doctor may treat patients by prescribing a bandage contact lens to wear while the patient is healing to prevent the eye from being exposed to too many irritants, so note this if you are seeing the patient in follow-up and they have their lens in. People with this type of injury are at a greater risk of infection or erosion so in most cases, it’s best not to touch the eye without the examination of a physician first.
Erosion/Corneal Melt Corneal melt or erosion is when a damaged or weakened cornea begins to thin, eroding layers off of the eye. Chronic use of anesthetic drops such as proparacaine or tetracaine can cause melt, but cocaine drops were the biggest offender for this, as far as drops go. This is why you hear about them and might see a question on them on a certification test, but never see
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cocaine drops in an office setting they are super potent. Erosion and melt can also be caused by an injury. Untreated lacerations can erode with time. A mild scrape that took off a chunk of the epithelium layer may become weaker and cause breakdown in the future. Recurrent erosion can cause severe, permanent damage and, unless told otherwise from your doc, do not give these patients any drops and avoid touching their eye in general.
Corneal Degeneration Where keratoconus is an outward protrusion of the corneal, corneal degenerations eat away at the peripheral cornea. Quite rare, Pellucid Marginal Degeneration (PMD) and Terrien Marginal Degeneration (TMD) cause decreased visual acuity. TMD, which causes thinning of the peripheral cornea, causes increased astigmatism and is often treated with glasses, RGP lenses, or lamellar keratoplasty [10]. PMD usually affects the inferior cornea in a crescent shape and is often confused with keratoconus in its early stages because of its presentation [11]. While surgical intervention may help patients with this form of corneal degeneration, laser refractive surgery is generally off the table. Dry Eye Dry eye is one of the most common complaints in optometry and ophthalmology. Grittiness, redness, pain, itching and even tearing all the telltale signs of dryness. The first four are a bit more obvious and, while excessive tearing sounds like it’d be the opposite of dryness, it actually occurs because the eye itself is dry and additional tears are being produced in an attempt to re-wet it. On our corneas, we have what is called a tear film. This film, which is comprised of three layers, is in place to keep our eyes moist: the oil or lipid layer, the water or aqueous layer and the mucin layer. The oil layer is the outermost layer, which can be remembered easier if you think oil/outer. The oils help keep the moisture in and help prevent our eyes from drying out.
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Keli B. O’Connor The middle layer is the aqueous layer. This layer cleans and moisturizes the eye. The innermost mucin layer (think muc-in) helps spread the middle layer all over the cornea to keep it clean while providing nourishment to the area. The meibomian glands located inside the eyelid produce an oil, appropriately called meibum, that helps prevent evaporation of tears. When the glands become clogged, they cannot produce the oils needed to keep the water in, therefore causing dryness. To treat this, doctors can either express the gland or use something called Intense Pulsed Light (IPL) which may help with meibomian gland dysfunction. Artificial tears, ointments, and supplements like omega-3 also help keep the eyes wet and the oil layer healthy. Auto-immune disorders can play a part in ocular dryness. Sjogren’s syndrome affects the glands that produce tears and saliva and therefore causes dryness in the eyes and mouth. People with thyroid issues might develop band keratopathy due to improper lid closure. Patients with ailments such as these will likely need a daily regimen of tears and ointments as well as systemic drugs to combat dryness. A great benchmark in determining the severity of dryness is by performing a Schirmer tear strip test. Each strip has a small divot cut into them to signify where the proper place to bend the strip and rest it onto the patient’s inner lower eyelid and a tiny millimeter ruler printed on it for measuring tears. This can be a little uncomfortable for the patient but they need to keep the strip in place with their eyes shut for five minutes before it can be removed to measure their tear production. Normal eyes yield about 10 mm of tears or more. Anything less than the 10mm line is indicative of dry eye [12].
Ulcers Corneal ulcers, like scratches, can present as red, painful eyes. Ulcers can develop from trauma, abrasions or lacerations that go unchecked for too long or by overusing contact lenses. Ulcers are treatable, but unlike
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some other types of corneal injury, bandage lenses are not prescribed to treat. In fact, doctors will tell these patients to not use their CLs for a couple of weeks until their eye has healed completely. Most people with ulcers will heal with no problems or permanent damage, but some won’t, especially if they continue to wear their lenses. Unlike many other types of ulcers, Mooren’s ulcers is a fast-spreading type of ulcerative keratitis [13]. Often confused with forms of corneal degeneration, Mooren’s ulcer doesn’t have any promising treatments and the visual prognosis is poor.
Corneal Dystrophies The cornea and its layers play a major part in how our eyes see. People with these issues may be completely asymptomatic but many with genetic corneal dystrophies suffer from vision loss. There are three major classifications of dystrophies – anterior, stromal and posterior. Anterior dystrophies, like Map Dot, affect the layers of the cornea most exterior, and posterior dystrophies, like Fuchs, affect the innermost layers. Stromal dystrophies, like Lattice or Macular Corneal Dystrophy, involve the middle layer of the cornea [14]. Corneal dystrophies are often treated with drops, gels, and even lasers, but severe cases may require a corneal transplant.
Globe Ruptures Globe ruptures aren’t as much as a cornea problem as they are an overall eye problem, but cornea specialists see them on occasion. Patients with ruptured globes typically present as a surgical emergency. The prognosis for visual recovery is poor despite surgery and many patients end up with some degree of vision loss, blindness, or perhaps a phthisis bulbi (or shrunken eye).
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Damaged Corneas and Transplants People who have suffered from severe vision loss from corneal damage may decide to pursue a cornea transplant, otherwise called a keratoplasty. The degree of transplants can vary between partial grafts to full-thickness and, though most are from human donors, some corneas can be artificial. Keratoplasties have a high success rate but are not foolproof. Corneas may become cloudy again, become infected or cause pain, so alert your physician if your patient reports any of these symptoms and only check their pressures once you’ve got an okay from the doctor. Since handheld tonometers only touch a small area of the cornea, your doctor may prefer this over the Goldmann tonometer.
Cornea Defects Superficial punctate keratitis, or SPK, occurs when cells on the epithelial layer die [15]. At times, you can see SPK without a slit lamp, but they glow under the cobalt light when the eye has been given fluorescein. SPK can look like tiny spots or clumps of speckles on the surface of the eye. Superficial punctate keratitis can be caused by a number of things, including dry eye, and is usually resolved with artificial tears or ointments [11].
Guttata Where SPK is on the surface of the cornea, guttata are speckles on the inside of the cornea on the endothelial layer [16]. Since SPK is on the front of the eye and guttata is in the back, fluorescein will not help you see these spots any better. To observe guttata, angle the light on the slit lamp. Shine the light on the front of the eye and it’ll illuminate the spots posteriorly.
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Fuchs’ Disease Like guttata, Fuchs’ disease presents as speckles along the endothelial layer [16]. Whereas guttata is sporadic, Fuchs’ is genetic. Unfortunately, there isn’t much to do to prevent either. Patients with Fuchs’ must be more careful about making and keeping their annual eye exams than others for this reason.
EXAMINATION A cornea history starts out a lot like a comprehensive note, but with extra information pertaining to the cornea. If they have cataracts, dry eye, injuries, or dystrophies, the history is the place to note it. A basic cornea note can look something like this: “Patient presents for a one month follow-up for keratoconus. She received her new RGP lenses and reports that her vision had improved. She denies flashes, floaters and eye pain at this time.”
Easy and concise. Patients with advanced pathology will no doubt need a more involved note, but this small note lets us know the purpose of the visit, how the patient’s vision is and that she doesn’t have any pain.
Conclusion Corneas are front and center in the eye and can be subject to a great deal of trouble from internal and external forces. The five layers of the cornea (Every Big Strong Dog Eats) play a role in keeping the eye healthy, strong and moist, therefore damage to any of these layers can be problematic. The cornea is responsible for a hefty chunk of our eyes’ vision and the shape of it can warp that vision in patients with keratoconus. Dry eyes are a common ailment and Schirmer’s strips are still the gold standard
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in checking dryness. Treatments for cornea issues can be as simple as topical artificial tears to corneal transplants and the cornea is so sensitive that even the smallest eyelash on the surface can feel like you need both.
Chapter 8
RETINA Retina can be a complex subspecialty, but technicians may find the work-ups and exams repetitive. If you are used to the hecticness and activity of comprehensive, retina might feel boring or monotonous, but the real fun of retina is the pathology, treatments, and photography. Some of the most common problems seen in retina are macular degeneration, retinopathy, and detachments, but the specialty expands well beyond these ailments.
AMD Age-Related Macular Degeneration (AMD or ARMD, for short) is a common cause of permanent vision loss that is most often seen in elderly Caucasian populations. AMD is usually referred to as being either dry or wet, where dry is atrophic and wet is honestly called “wet” because of bleeding and leakage of vessels within the eye.
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Dry AMD makes up about eight or nine out of ten AMD cases, leaving one to two that have developed into the wet type. Dry AMD isn’t as much treated as it is prevented, with the focus being on supplements like PreserVision AREDS 2 to delay or possibly prevent the degeneration from turning wet. Otherwise known as exudative or neovascular age-related macular degeneration because of the new growth of blood vessels in the retina, wet AMD is treated with intraocular anti-VEGF injections (Avastin, Lucentis, Eylea, etc.) and occasionally with laser to seal off leaking vessels.
RETINOPATHY Retinopathy is a broad term for disease of the retina. There are seemingly countless types of retinopathy with varying degrees of severity. These are usually classified as mild, moderate and severe. Mild, or in some cases referred to as minimal, atrophy is monitored by the physician based on retina findings, so follow-ups may be every few months to once or twice a year. Those with moderate retinopathy are usually seen in clinic more frequently, maybe once every two to three months and patients with severe cases typically follow-up monthly. Light-colored, fluffy looking patches of retina called cotton wool spots are sometimes found in patients with various retinopathies, like those related to diabetes and hypertension. If retinopathies are not treated early, they can result in permanent vision loss.
Diabetic Retinopathy In clinic, diabetic retinopathy is the most commonly seen and treated retinopathy [18]. In addition to the three previous classifications of severity, there is an additional stage called proliferative. This stage is the most severe in diabetic retinopathy.
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Insurance companies grant one diabetic eye exam annually, even if the person has no ocular pathology, but once retinopathy is spotted, patients are monitored more aggressively. Depending on the doctor’s findings, a person with diabetic retinopathy could be treated with injections (just as they would with AMD) or laser. The goal of the physician is to seal off leaking vessels and prevent new ones from forming. When working up diabetic patients, always include what and when their last blood sugar was, what and when their last A1C was, what oral medications they take, if they are on insulin and when they were diagnosed with DM. If a patient has had previous injections or lasers, add these into the HPI as well.
Hypertensive Retinopathy Though diabetic retinopathy is the most common, there are many more types of retinopathy. Hypertensive retinopathy is pretty common in retina and, like the diabetic variety, can be treated with injections. Physicians will do everything they can to avoid this, so most patients will be placed on oral meds and told to make lifestyle changes to reduce their blood pressure. When the patient comes in, note any medications they are currently taking and ask what their last and average blood pressure readings are. While many people can see results without treatment, patients with chronic hypertensive retinopathy experience permanent damage. You may see a note that says AV (arteriovenous) nicking or copper wiring this means that they are advanced. People may also present with cotton wool spots (CWS) or hard yellow exudates [19].
Central Serous Retinopathy Central serous retinopathy is still kind of a mystery to doctors. They may not know 100% what causes the disease, but we know that being between the ages of 30 and 50, stress and certain medications, like
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corticosteroids, can put a person at greater risk for developing CSR. Central serous retinopathy occurs when fluid builds up under the retina [20]. Patients with CSR may complain of new blur or a central vision defect so ask questions that reveal when these symptoms were first noticed. Usually, CSR resolves on its own but laser treatments can be performed alongside the discontinuation of any steroids and other lifestyle changes. Be sure to ask about any specific changes that the doctor recommended having your patient make at all follow-up visits. Hereditary Retinal Degeneration Genetic mutations can, unfortunately, cause normal parts of the body to malfunction or not develop at all. Hereditary retinal degeneration, or HRDs, run in families and can cause significant vision problems in childhood or throughout adulthood. Leber’s congenital amaurosis, choroideremia, conerod dystrophies, and other disorders under the blanket of pigmentosa can be passed from parent to child and cause gross to complete vision loss. Progressive vision loss from HRDs used to mean permanent blindness in those who have them but treatments are being developed to combat them. Gene therapy drugs like Luxturna are being administered to children and adults with HRDs with promising results. Researchers are continuing to study new gene therapies for other disorders of the eye and other parts of the body.
Solar Retinopathy Sometimes the sun, the provider of light and life on our planet, can hurt us. Even though the yellow dwarf star is almost 93 million miles away from us, we all know that too much sun can be a bad thing because of its ability to burn and dehydrate us. Sometimes sunlight exposure can cause solar retinopathy. When a patient comes in with this diagnosis, find out how much exposure to the sun they’ve had. Do they work outside? Have they recently vacationed somewhere sunny? Do they tan? Did they straight
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up just look right at the sun?? All of this info helps the doctor better educate the patient to ensure that he or she avoids further exposure in the future.
Eclipse Retinopathy In August 2017, all that Americans could talk about was this rare solar eclipse that, admittedly, was fascinating. Behind the scenes, every publication geared toward techs, optometrists, and ophthalmologists was secretly waiting to pounce on any fundus photography they could get ahold of on the effects of eclipse retinopathy. Only a few across the country have had true cases of this, but learning about the effects of this rare injury can help techs understand how dangerous the sun can be for the eyes.
Laser Retinopathy Another less common form of retinopathy is laser retinopathy. It is crucial to ask questions and unearth what caused the damage to the retina in these cases. As an example, I saw a child with round laser spots burned into his retina from a laser pointer. He didn’t want to admit that he had been playing with a laser at first, especially because his mom was in the room and she didn’t allow laser pointers in her house for this exact reason. After some prodding, the boy revealed that he and his brother found the laser pointer that his mom previously took away from them and they played games where they shined the light into the mirror at each other. All it took was one streak of direct exposure and his vision was permanently reduced from 20/20 to 20/200.
HIV Retinopathy Some of the sweetest, funniest and most joyful patients that we see are patients with HIV or AIDs. Several health initiatives provide low-income
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HIV+ patients with free eye exams. If that patient makes it into a retina appointment, it may be because they have developed HIV retinopathy. This microvasculopathy used to be found in over half the population of HIV/AIDS patients, but the use of certain medications have greatly reduced this number [21]. HIV retinopathy often presents with cotton wool spots, similar to those found in diabetic or hypertensive retinopathies. On top of screening medications, ask your patient about the date of their diagnosis and recent labs. Their CD4 count is particularly significant. Beyond your normal questions, treat your patients with the dignity and respect that they deserve. I cannot tell you how many times I have had HIV+ patients tell me that I was the first tech to treat them like a “regular person”. All patients deserve to be treated like a “regular person” because they are all regular people. The questions you ask and the steps you take may change from person to person, but a patient should never, under any circumstance, feel that they were treated like a lesser person for any reason.
Radiation Retinopathy On occasion, a person with cancer or another illness that requires radiation therapy develops radiation retinopathy. As one could guess, history is going to be huge here. Note the type of cancer, when the original diagnosis was and the dates of radiation treatments. In addition to radiation retinopathy, patients with a cancer diagnosis, especially that of breast or lung cancer, are more likely to have cancerous growths within the eye (more on cancers back on page 76). Uveitis The uvea consists of the iris, choroid, and the ciliary body. We all know that the iris is the colored part of the eye, but the other two parts aren’t as commonly known if you’re new to eyecare. The choroid is the layer sandwiched in between the retina and the sclera and the ciliary body is what connects the choroid to the iris. Inflammation of the uvea or any of its parts is called uveitis.
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Uveitis, otherwise known as chorioretinitis, is a relatively rare condition that can present in people with auto-immune disorders but also occurs after an eye injury or infection. Patients with uveitis may complain of pain, redness, light sensitivity (photophobia), floaters, or smaller than normal pupil [24]. The four most common forms of uveitis are anterior or iritis, intermediate or vitritis, posterior and panuveitis, which involves the entire uvea. When treating uveitis, the physician needs to treat the eye as well as the underlying systemic causes of the inflammation. Be sure to include any diagnoses of auto-immune diseases, along with any history of steroid and immunosuppressive medications, in your note. For follow-up exams, be sure to record if the patient is taking dilating drops as a therapy and when the last drops were taken.
Saturday Night Retinopathy Saturday Night Retinopathy is extremely rare but I wanted to mention it because it is so wild. Patients with this form develop it after falling while under the influence of drugs or alcohol (hence the name). Once down, the patient stays in that position for an extended period, be it from sleep or passing out, and awake to find that their vision (unilaterally or bilaterally) is gone. This perfect storm of the trauma, remaining face down afterward, and CRVO/CRAO with possible ptosis, paralysis of the eye muscles (ophthalmoplegia), and nerve damage can result in permanent complete vision loss.
ARTERY AND VEIN OCCLUSIONS Another common family of problems seen in retina is that of artery and vein occlusions which are also occasionally referred to as “eye strokes”. Both types of occlusions are classified as either Branch or Central, the difference being that Branch Occlusions are blockages of the
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smaller branch vessels whereas central refers to blockages of the main vein or artery [23]. With both Artery and Vein Occlusions, Branch is a more common finding than Central.
Artery Occlusions Patients with Artery Occlusions have different symptoms and presentations in their fundus exams and photos. People with Central Retinal Artery Occlusion (CRAO) have sudden, painless vision loss and an APD while patients with Branch Retinal Artery Occlusions (BRAO) will have varying visual field defects depending on the location of the occlusion. The fundus of someone with CRAO looks pale and washed out while the fundus of a person with BRAO might only look this way for about half of the retina.
Vein Occlusions People with Vein Occlusions are, in some cases, less symptomatic and may not seek treatment immediately because of this. A person with Branch Retinal Vein Occlusion (BRVO) may have some blurred vision or even a small area of blur in an eye and people with Central Retinal Vein Occlusions (CRVO) have a more generalized blur or even complete loss of vision in one eye. The retina for these two also looks vastly different. BRVOs tend to have some hemorrhages and edema along a single branch in the retina while CRVOs have hemorrhages and edema everywhere.
DETACHMENTS Some patients see flashes. Many have floaters. Having a combination of the two, especially if the floater resembles a curtain or a veil, can be a sign of something serious, like a retinal detachment.
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Retinal Detachments and Tears A retinal detachment, or RD, occurs when a piece of the retina breaks away from the rest, causing flashes that can resemble lightning bolts and large, curtain-like floaters. If mild and treated promptly, patients may heal to have little vision loss. Left untreated and patients may have substantial vision loss. Larger, more severe detachments may cause vision loss regardless of how quickly it was treated. The 4 F’s of RDs 1. Flashes 2. Floaters 3. Field Loss 5. Falling VAs Retinal detachments can be caused by trauma or occur naturally in those who are highly myopic, as their retina is thinner. Minor detachments may heal well with laser, cryopexy (freezing of the site) or pneumatic retinopexy, where the surgeon freezes and injects a bubble into the eye to hold everything in place²⁵. More involved RDs require more involved surgeries, like vitrectomies and scleral buckles. In a vitrectomy, the vitreous is removed and replaced with either a bubble, like in a retinopexy, or oil. The bubble slowly lessens and vision improves during this time. Oil does not dissolve and will require another procedure to remove it after the detachment has healed. Scleral buckles are bands that are surgically wrapped around the eye and combined with vitrectomies for severe detachments. Ophthalmologists can perform laser treatments in conjunction with the other surgeries as well. As myopic eyes are longer than average, the retina can be stretched to fit it. Think of lattice degeneration as kind of like stretch marks in the retina of elongated, myopic eyeballs.
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Like their cousin the retinal detachment, tears are breaks in the retina which can cause flashes and floaters. Some tears heal on their own with no vision loss and others require laser to fix them. Oncology Cancer is terrifying, but thanks to medical advances, it isn’t necessarily a death sentence anymore. Eye cancers can affect various parts of the eye and, depending on various factors, patients can have little vision loss to total blindness. Some may require enucleation to prevent spreading. The retina is one of the most commonly affected areas, but tumors can grow on the iris, sclera, lids and lacrimal glands. Cancers can originate in the eye (primary cancer) or grow in the eye after the cancer has spread from other parts of the body (secondary cancer). The five types of primary eye cancers we see are melanoma, lymphoma, squamous cell, and the two childhood cancers, retinoblastoma and medulloepithelioma [23]. Kids are so adaptive and don’t have a reference point of what “normal “vision should look like, so they are less likely to complain if they have poor or worsening vision. Because of this, the first sign that something is even wrong might be from abnormal-looking eyes in a photo. When light strikes the eye in a certain way, it can illuminate the back of the eye, causing a red reflex and making it look red in pictures. If the light from a camera causes the pupil to appear red in one eye but white in another, a tumor can be preventing the red reflex. The difference in pupillary appearance is usually enough to get some parents to consult an eye doctor (or WebMD) and the proper diagnosis can be made, but other cancers are found incidentally during a routine eye exam. Adults may have the same white reflex in photos, but more often they’ll notice a change in vision as the cancer worsens. Oncologists will treat ocular cancers with laser, radiation, and surgery to remove all or part of the eye to clear away the cancer and prevent it from spreading further. After their treatments, and even after remission, these patients will need to be closely monitored to make sure the eye is healthy and that no further complications arise.
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Posterior Vitreous Detachments A posterior vitreous detachment, or PVD, is similar to an RD, but often with fewer flashes and floaters. These occur when part of the vitreous gel detaches from the eye. PVDs can heal on their own and the symptoms usually resolve without assistance over time. Sometimes a small circular floater is left after a PVD. This residual floater is called a Weiss ring. Weiss rings can float into a patient’s line of sight and complain about a round floater that comes and goes. These rings can be appear brown or grey during the fundus exam and may be partial or full [26].
Epiretinal Membranes Epiretinal membranes, or ERMs for short, occur when scar tissue develops on the retina [27]. ERMs are sometimes referred to as wrinkles or puckers because of their appearance and can be treated with a vitrectomy, much like a detachment. During the surgery, the surgeon peels the membrane away with tiny forceps before introducing the bubble. With all vitrectomies, vision will be very poor directly following the surgery and will gradually improve over a six-month period. They may not have 20/20 vision ever again, but they keep sight, which is better than the alternative.
EXAMINATION As you can see, there is a lot that can go wrong with a person’s retina. When getting them ready to see the doctor, try to get an idea of what type of pathology they were referred for and add in some information that the physician will find important to the problem. For example, if your patient is a diabetic, a sample history might look like this:
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Keli B. O’Connor “Patient presents for 4 week follow-up for bilateral proliferative diabetic retinopathy with macular edema in the right eye. He states that his vision has improved since his last injection of Eylea in the right eye on MM/DD/YYYY. He reports that he initially had floaters after the last treatment, but they resolved in a few days. He denies flashes and eye pain at this time. “Patient’s last A1C was 8.5 on MM/DD/YYYY. His blood sugar was 137 upon waking this morning.”
This note details why the patient is being seen, what his last A1C was, what his waking blood sugar was and when his last treatment was. The treating doctor has a wealth of information about this patient in just a matter of sentences. Some doctors will want more details than this and some will want less. Once you work with a doctor a few times, you get a feel for what they want and will be able to replicate it.
Conclusion The retina is a complex and fascinating part of the eye. With so many working parts, it’s easy to see how a small problem can cause major vision loss. There are ten layers of the retina and retina physicians also treat the vitreous and uvea, as they are all interlinked. While retinopathies, degenerations, detachments, and floaters are some of the more commonly seen problems in this subspecialty, a multitude of genetic disorders are also likely to come up in clinic and researchers are working hard to find treatments for them.
Chapter 9
NEURO-OPHTHALMOLOGY Neuro-ophthalmology is the complex field where eyecare meets neurology. However, is complicated as this subspecialty is, it is equally fascinating. Neuro-ophth is the subspecialty of ophthalmology that deals with how the eyes communicate to the brain and vice versa. Some of the most common issues seen in neuro are strabismus, visual field defects, pupillary defects optic nerve disorders, and giant cell arteritis. The spectrum of diseases and dysfunctions is vast, with some of the focus on the nerve and vision loss with others on the surrounding muscles or even the brain itself. No matter the pathology, all neuro-ophthalmic patients need a thorough history.
STRABISMUS Disorders of the extraocular muscles (EOMs), or strabismus, are probably the most commonly seen diagnoses in neuro-ophthalmology. To better understand EOM disorders, you have to have an understanding of the muscles themselves.
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There are six EOMs that surround the eye and control eye movement: the four recti muscles (superior, inferior, lateral, and medial) and the two obliques (superior and inferior). See page 13 for more on the specifics of the muscles and their jobs.
Phorias vs Tropias Pretty much everyone confuses these terms at first, so it is okay if you’re confused, too. Tropias are permanent and phorias are latent, or they can be hidden or suppressed. Phorias can surface naturally when the patient is tired or can be teased out of them with cover/uncover testing. To remember the difference, think that tropias trump the eye muscles and phorias fake us out and need to be elicited. Nystagmus is a jerky, involuntary movement of the eyes. Vision in patients with this condition, which can be either congenital or acquired through trauma, is generally terrible monocularly. Because of this, it is best to have the patient fog an eye instead of completely occluding it for both visual acuity and refraction.
Directions Eye turn is typically categorized in four different directions: exo-, eso, hyper- and hypo-. For exo-, the eye turns outward, occasionally called “wall-eyed”. In eso-patients, the eye turns inward, or is “cross-eyed”. Hyper- patients have an eye that is turned upward while hypo- patients have an eye that turns downward. For these, remember: Exo Outside, like an exo-skeleton Eso Harder to find a mnemonic for so I just think “eso/inside” Hyper I think of hyperactive kids, always hyped up with energy Hypo Weighed down by a heavy hippo
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Cranial Nerves and Palsies There is a total of 12 cranial nerves, but neuro-ophthalmology really only deals with nerves II, III, IV, VI, and VII.
CN2 Optic Nerve As one could guess, problems with the optic nerve cause vision trouble. Since we are just looking into palsies, for now, we will come back to CN2 in a bit.
CN3 Oculomotor Nerve Cranial Nerve III is a powerhouse. This nerve is in control of all but two EOMs. The oculomotor nerve innervates the superior, inferior and medial recti, the inferior oblique, the levator palpebrae (which controls the upper eyelids), the constrictor pupillae (for pupil constriction) and the ciliary muscles. Since this nerve is in charge of the muscles that move the eye up, down, in and torsionally (in and up), a third nerve palsy could cause an ocular misalignment and diplopia. Palsies of CN3 also often result in pupillary defects (affected side cannot constrict) and ptosis (affected upper lid may not open or close properly) [28].
CN4 Trochlear Nerve The fourth cranial nerve innervates the superior oblique. When this nerve is damaged or palsied, the eye has trouble moving in toward the nose, side to side or downward (remember- the SO is one of those torsional
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muscles). Patients with a fourth nerve palsy usually experience double vision in downgaze and often complain that their diplopia is worse when reading, as people generally lower their sight to read. Creating a mnemonic for this was a bit rough so try to remember SOFO (Superior Oblique FOur) [29].
CN6 Abducens Nerve The final nerve that we’re going to pay close attention to is the sixth nerve, or the Abducens Nerve. CN6 innervates the eyes’ lateral rectus muscles, which control the movement of the eye temporally, or towards the ear. To help remember this, think adduct adds toward the face so to abduct is to take away from the face (like abolish). Because the medial rectus has nothing to keep it in check, patients with a sixth nerve palsy present with esotropia and constant horizontal diplopia which is worse at distance. CN6 palsies are the most commonly seen nerve palsies seen in ophthalmology [30].
CN7 Facial Nerve Cranial nerve VII is the facial nerve and in ophthalmology, controls of lacrimal glands. Palsies of this nerve cause facial, or Bell’s palsies, are seen in neuro, but they do not innervate any extraocular muscles. Patients with facial palsies may have one sided face droop and ptosis for the duration of their palsy.
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THE OPTIC NERVE The optic nerve, or CN2, is an important nerve for many aspects of eyecare. In neuro, we deal with the optic nerve (ON) quite often. Common problems include, but are definitely not limited to, papilledema, pseudopapilledema, optic atrophy, optic neuritis, neuropathy, idiopathic intracranial hypertension (IIH, or PTC which stands for the archaic term “pseudotumor cerebri”), drusen, asymmetry, and nutritional amblyopia. While ON issues are typically monocular, meaning they only affect one eye, certain problems can affect both, so careful documentation of visual acuities and confrontational fields are paramount. Dysfunction of the optic nerve can lead to a patient having diminished color vision, so checking each eye individually with Ishihara plates should be added into your workup, if your practice doesn’t make color plates mandatory with each exam. A complaint of “vision loss” could mean a multitude of different things Does the patient have 20/100 vision in their right eye when it was last documented at 20/25? Are they CF 3 feet in their left eye but 20/40 in their right? Do they have a temporal defect in one eye? Does the vision in their left eye appear dimmer than that of their other eye? Document all of it and be as specific as possible. Normally, for a patient to make it onto a neuro-ophthalmologist’s schedule, they will pass through at least one or two other physicians. Whether they’ve only seen their primary optometrist, or they’ve been to their primary ophthalmologist, primary care physician, retina specialist, neurologist, endocrinologist, etc., the person you are about to examine probably has a lengthy paper trail behind them. Use this to your advantage. The information in someone’s past notes can potentially make your life significantly easier, especially because extracting that same info from a patient can sometimes seem more difficult than applanating yourself (which I do not advise doing). In the event that your patient is a poor historian, fill in the blanks that you can and finish your note with “Patient is a poor historian”.
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More poor historians wander into the neuro clinic than any other subspecialty. As frustrating as this may be, don’t get upset at them. Many patients have had strokes which makes speech difficult and can affect their memory. Patients with cancer may be on medications that alter their ability to recall information or could have cancer that metastasized to the brain, hindering some cognitive function. Victims of brain injuries may have cognitive issues that they will have for the rest of their lives. These patients are coming to us for help. Do what you can to help them. Hold an occlude for them, repeat instructions. No matter how frustrated you are during the workup, you can bet that the person in the exam chair is just as, if not more, frustrated and maybe even embarrassed. Our job is to help them. Visual Field Defects Patients with optic nerve issues, IIH, stroke or brain masses often present with visual field defects. Some people have field cuts that are large and alter their vision, others have cuts that they’ve never noticed until having a tech perform a confrontation field and discovering it (hint: this is why confrontation fields are imperative for ALL patients). Knowing what the common losses look like can be very helpful in guiding you through your exam and knowing the right questions to ask. A diagram of visual field defects can be found in the Visual Field chapter on page 101.
EXAMINATION Did your patient patch as a child? When was their cataract surgery? What hypertension meds are they on? Tinnitus? Jaw Pain? How often are your headaches? Do you experience trouble swallowing? Anything and everything needs to go into your note. Labs, imaging, scans, visual fields, OCTs, photos and notes from referring and supporting physicians all need to be included with your workup. If you don’t have that info, you need to obtain it. Worried that you have too much info for your doctor? You don’t.
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History The following are some examples of what a neuro-ophthalmic history could look like. Directly below is a typical write up for a new patient with double vision: “New patient presents referred by Dr. Whoever for an evaluation of binocular horizontal diplopia; she first noticed her intermittent double vision at distance upon waking two days ago (MM/DD/YYY). She reports that her double vision is worst in left gaze and when she is tired at night. Patient has a history of bilateral cataract surgery 2 months ago (MM/YYYY), hyperthyroidism, Type II Diabetes, and hypertension. She wears over the counter readers for near and denies flashes, floaters and eye pain at this time. “Patient had an MRI of the orbit on MM/DD/YYYY.”
When your patient’s chief complaint is double vision, ALWAYS specify whether it is monocular or binocular and whether it is vertical, horizontal or diagonal. In the previous history, I established from the start that the patient is new, who referred the patient and what the chief complaint is in the first half of the first sentence. The second half of the first sentence and the following sentence include some modifiers, like when it began and when it typically occurs. I wrapped up with the patient’s pertinent history that could relate to the visit, report that they deny other potential eye emergencies and included the date of the latest imaging that relates to the complaint for the doctor to reference later. “New patient presents referred by Dr. Whoever for an evaluation of a left NAION; he was seen in the emergency room on MM/DD/YYYY after experiencing sudden painless vision loss last Thursday. His blood pressure was 210/145 when he was admitted to the ER and he has had uncontrolled hypertension for over 20 years (diagnosed YYYY). He
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Keli B. O’Connor currently takes 100 mg metoprolol, 40 mg lisinopril, and 20 mg furosemide. He denies flashes, floaters and eye pain at this time. “Patient had labs on MM/DD/YYYY and an HVF this morning.”
In this history, I included pertinent information such as specific dates of the vision loss, his blood pressure at the time of admittance, his current medications with doses and special testing. When documenting visual field testing in neuro, just as in glaucoma, always specify the machine used whether it’s a Goldmann (GVF), Humphry (HVF), Octopus (OVF) or whatever other perimeter that your practice has. Ophthalmology is our primary focus in medicine, but knowing about systemic diseases and treatments is important for working up patients, especially in neuro-ophthalmology. When a patient has complaints that all of their other doctors cannot explain, they often end up in neuro for answers. Exhaustive as it may seem, we need to document every single medication, diagnosis, surgery and pertinent social and family histories that the patient may have. This doesn’t end at the first new patient exam we have to treat every follow-up as if we have never seen this patient before to make sure we aren’t missing anything. All practices are different and all doctors have a different way they’d like their patient to be teched up, but knowing the systemic problems while focusing on ocular and neurological issues will give you a great starting point. Some doctors prefer extra testing to accompany the work up exam. The Worth Four Dot test is a common test for determining the presence of diplopia or the suppression of vision from an eye. The patient wears a pair of glasses with one green lens and one red. They are asked to look at a target of four dots – a red, a white, and two green. If the white spot alternates, vision is normal. If any of the lights are missing, there is suppression, and if they see more than four dots, there may be diplopia. Neuro-ophthalmologists are often referred patients with pupillary defects, which you can read more about in the Comprehensive chapter. Many neuro-ophthalmologists prefer to see patients undilated so they can measure and record all pupil sizes, restrictions, and APDs. When
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measuring strabismus, they will always check EOMs and use either prism bars or loose prisms (at times, techs may refract or use bars, but this is up to the doctor and the practice). In the social history, asking about smoking status and alcohol usage is crucial, as alcoholism can lead to a B-12 deficiency and cause ON issues and patients with thyroid eye disease can exacerbate and trigger symptoms if they smoke.
Conclusion Neuro is neat. Instead of just focusing on the eye itself, we look at the eye, brain and muscles and their roles in our vision. The four recti and two oblique muscles move the eye in different directions and problems with the can cause double vision. Three of the twelve cranial nerves innervate the extraocular muscles and one, the optic nerve, gives us sight. When the optic nerve is damaged, it can cause vision loss in the form of decreased acuity, color perception, and visual defect defects.
Chapter 10
OCULOPLASTICS When many people hear the term “plastics” they think cosmetic surgery and, even if there are some cosmetic procedures in oculoplastics, the subspecialty is far from vanity lid lifts and Botox injections. Oculoplastics is fascinating. Plastics clinics see patients who are in search of ways to slow down the natural signs of aging to gunshot wounds that resulted in enucleation and cancers that affect the lids and eyes. Of course, all of these exams look drastically different, but generally, the workup is about the same across the board. Much like neuro-ophthalmology, plastics requires a hearty history. When did you first notice this chalazion? How did this injury to the eye occur? What procedures, imaging, and medications have you had since your cancer diagnosis? When did you first notice your eye twitching? You may not have to compile as many labs or imaging reports as you would in neuro, but external photography and visual fields are huge in this field. Ask your patient to bring old photos of themselves in for their first appointment if they are coming in for lid problems. If the patient is already in the exam chair and this is your first encounter with them, ask them to bring the pictures at their next follow-up. Oculoplastic physicians order lots of external photographs to track issues like ptosis and proptosis, so noting when their last photo was taken is very helpful. Ptosis visual fields
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are often given to patients with lid droops and inclusion of this in your write up is also important. Plastics deals with the external parts of the eye, like the lids and lashes, as well as the orbit itself.
LIDS Eyelids help keep our eyes wet and protect them from being damaged by the world around us. We naturally want to close our eyes when we perceive danger or when something unexpectedly comes too close to our faces like bugs, dirt or other foreign bodies. Unfortunately, there are times when our lids cause more harm than good.
Trichiasis and Entropion From our four eyelids, we grow eyelashes. Our lashes are sort of like hairy extensions of our lids that trap stuff that isn’t supposed to get into our eyes before it makes it there. Lashes are supposed to grow outward and away from the eye but occasionally, they point inward toward the eye. This is called trichiasis. Aside from being extremely uncomfortable, as the eyelashes are sweeping over the eye with every blink, the repetitive scraping of these lashes could potentially cause damage to the cornea. A single or cluster of lashes from one or both lids of an eye may stray from the rest and grow inward, but entire rows of lashes can grow in toward the eye and cause intense discomfort. This can either be caused by the individual hairs growing in the wrong direction or by the inward turn of an eyelid. Entropion, or the inward turn of the eyelid (usually the lower ones), is often genetic. Doctors may treat the irritation of entropion with artificial tears or ointment and may treat with lid tape in moderate cases. Those with severe entropion may benefit from electrolysis to remove lashes with
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electricity, cryotherapy to freeze the lash follicles, or lid surgery to rotate the lid outward if the lashes continue to damage or ulcerate the cornea [32].
Ectropion Entropion is when the lid points inward and ectropion is when the lid – again, typically the bottom – turns outward. Since the bottom lid has drooped away from the eye, the eye itself can become very dry, causing excessive tearing that pools in the lower lid [32]. Additionally, patients may experience other dry eye symptoms including photophobia and pain, which physicians can treat in the short term with wetting drops and ointments. More severe cases may warrant lid surgery, but artificial tears may still be prescribed afterward to prevent further dryness. Whereas entropion is normally genetic, ectropion is rarely so; people can develop lower lid droop with age, facial paralysis or even from scar tissue around the eye.
Ptosis Where ectropion is generally a baggy bottom lid, a ptosis is a droopy upper lid. Ptosis can be caused by several things like eye trauma, head trauma, brain tumor, Horner’s syndrome, myasthenia gravis (MG), etc., but lid droop can just be caused by plain old age. It is common for people to have lid lift surgery for cosmetic purposes but doctors may perform the procedure on patients with severe ptosis that obscures vision in one or both eyes. If the droop has an underlying neurological factor, this may need to be treated prior to surgery. In some cases, like those with MG, medications can help improve ptoses.
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Proptosis Not to be confused with ptosis, Proptosis, or exophthalmos, is the bulging of one or both eyes. Most cases of proptosis are related to thyroid eye disease but they can sometimes be caused by mass growing behind the eye, pressing it outward, or occasionally orbital trauma. Orbital decompressions are a surgical procedure that helps alleviate proptosis in certain exophthalmic cases, but usually, the underlying cause of the bulging needs to be addressed before surgery. The amount of bulging is measured with an instrument called an exophthalmometer, which is sometimes referred to as a Hertel in the same way that tissues are sometimes called Kleenex. The Hertel exophthalmometer consists of a bar with a fixed end and a moveable piece that’s used to adjust for width. To use it, place the supports of the Hertel along the lower outer canthus at the orbital wall³¹. Using the internal mirror, gauge each opened eye separately using your mirroring eye (your right being their left and vice versa). You can read the position of their corneal apex from the millimeter markings on the instrument.
Lagophthalmos When people are unable to fully blink, they have what is called lagophthalmos. Though one can have both exophthalmos and lagophthalmos when the lids cannot fully close around the protruding eye(s), they are two completely different diagnoses. Patients may have no proptosis whatsoever but still have trouble fully blinking caused by a facial nerve palsy or traumatic injury. People with lagophthalmos, especially nocturnal lagophthalmos (cannot close eyes while sleeping), risk dry eye and band keratitis, so an artificial tear and ointment regimen is important for keeping the eyes moist.
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Lid Lag While it is easy to confuse with lagophthalmos, lid lag is when the upper eyelid is opened up higher than what it should be. In patients with lid lag, the natural reaction of the upper lid lowering in downgaze is absent. Like lid retraction or proptosis, it is often a symptom of a thyroid disorder.
Dermatochalasis As we age, things begin to sag. Saggy, baggy eyelids, or dermatochalasis, are a common complaint among older patients. Though some of these complaints are based on appearance alone, others complain because the lid is obstructing their vision. Dermatochalasis of the upper lid can sag over the eye, causing a superior visual field defect and a surgery called blepharoplasty can correct this. Upper lid blepharoplasty may be covered under insurance if deemed medically necessary, lower lid surgery is almost always considered cosmetic. If your physician is performing both upper and lower lid surgery, they will most likely need to bill separately for them.
Myokymia and Blepharospasm Myokymia is the term used to describe twitching of the eyes. Often unilateral, these twitches may be annoying but are typically mild in nature. Blepharospasm is the involuntary forced closure of an eyelid, as the prefix “blepharo” means eyelid and a spasm is an involuntary jerk. Twitching can be caused by a number of factors like stress, dehydration and/or lack of sleep and usually eliminating those things improves the spasms. When the spasm is more violent, physicians might decide to inject Botox or Xeomin around the eye or eyes to dull the twitching. As a last resort, a patient may undergo a myectomy, or a surgical procedure where a little muscle or nerve is removed to prevent eye spasms. Rarely, myokymias are caused by an
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underlying neurological issue; blepharospasms may be and for further testing and imaging may be required for these patients.
Blepharitis Since -itis means “inflammation” and we know “blepharo” means eyelid, we could gauge that blepharitis is an inflammation of the eyelid or lids. Patients with blepharitis may have red, dry and crusty eyes and might experience some blur or eye pain. Those who have this condition mildly will probably have some relief with the use of artificial tears but will benefit more so from warm compresses and lid scrubs. Thyroid Eye Disease Thyroid eye disease (TED) is complicated. TED is a set of eye problems that are a result of hypothyroidism, hyperthyroidism and their various forms like Graves’ and Hashimoto’s. TED symptoms are rarer for people with hypothyroidism, but it is not unheard of. Patients with TED typically take some sort of thyroid medication like levothyroxine or methimazole and these meds need to be noted down to the microgram. The physician will need to know if your patient has ever had radioactive iodine treatments, thyroidectomies and any other medications that they’d ever taken for their thyroid dysfunction. TED has two phases active and inactive. When a patient is inactive, their current problems if any aren’t getting any worse. When a patient is active, they develop the various symptoms of the disease. They may experience dry eye, which can be attributed to proptosis. In active TED, proptosis can be very pronounced, preventing lids from closing completely, causing redness, swelling and a whole mess of other symptoms. Folks with thyroid eye disease can also experience binocular diplopia, optic nerve damage, and exposure keratopathy.
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GROWTHS Lumps, bumps, and other growths are generally the most seen ailment in sick appointments and are a common finding in routine eye exams. Here is a quick breakdown of a few different kinds one might see in the office.
Chalazia and Styes A more commonly seen group of ailments in plastics are the various lumps and bumps around the eyes. Styes make up a sizable chunk of these. A stye is a little bump, typically along the lash line, that can cause irritation when blinking. These bumps are caused by a meibomian gland blockage or inflamed lash follicle. The proper term for an infectious stye in the inner part of the lid is a hordeolum³⁵. A chalazion is a larger, non-infectious lump that tends to be further out for the lash line. Most often, they don’t cause any discomfort as styes do. Chalazia are caused by clogged glands and, like styes and hordeolums, are relieved with warm compresses. Stubborn chalazia can be removed via a quick in-office procedure.
Other Growths Not all eyelid growths are caused by blocked pores or follicles. Warts, skin tags (acrochordons), benign papillomas and malignant lesions can all pop up in a plastics clinic and it can be difficult to tell these growths apart. Regardless of what the growth is, oculoplastics physicians can remove it and send the lesion to a pathologist for testing to make sure it isn’t cancerous. Smaller or shallower spots can be done in-house but those that have a deeper core or take up a larger area may have to be performed in the operating room. Most often, patients with benign results will be sent back to their primary ophthalmologist with plastics follow-up as needed
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while people with malignant findings are referred out to an oncologist ASAP.
MAJOR SURGICAL PROCEDURES Whereas most ophthalmologists operate on the eye or, rather, a particular part of the eye, oculoplastics physicians focus on the periocular region, or more simply put, the area that surrounds the eye and orbit. Occasionally, surgeons have to remove all or part of the eye. Evisceration is when the contents of the eye and the cornea are removed, leaving the sclera behind and enucleation is the complete removal of the globe. Naturally, doctors will perform these radical procedures as a last-ditch effort if the eye has no vision and is causing pain, is inflamed or is cosmetically unappealing [34]. Fast-growing malignant tumors can easily spread throughout the body, especially to the brain and physicians may remove the eye with the tumor to halt and prevent future growth. During the procedure, the surgeon may implant a ball or hunk of a surgical grade material into the orbit to give the appearance of fullness in the area, like the eye is there, but the lids are shut instead of having it look sunken in. Many people elect to have a prosthetic eye made afterward to match their other eye’s color and pattern. These pop in and out as the patient pleases. The constant use of a prosthetic eye can cause damage to the soft tissue around it, requiring additional surgery down the road. The ophthalmologist will discuss all of the options with the patient and refer to an ocularist, or the person who makes and cares for ocular prosthetics, should the patient go that route. Sometimes, plastics physicians will perform surgeries on the outside of the eye to help the eye itself. A tarsorrhaphy is a procedure that involves suturing all or part of the lid margins together to help the cornea heal from advanced corneal injuries. This procedure is often temporary but can be permanent, depending on the problem that warrants it.
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EXAMINATION Where some pathology cannot be immediately seen without a slit lamp, a good amount of plastic issues can be. Droops, bumps and lash problems can be apparent without being pointed out in some instances. For your history, be sure to document what the patient is complaining about and mention any findings that you may see as well: “Patient presents for 1 week post-op s/p chalazion removal. He reports that the area is tender and today it appears slightly swollen. He complains of occasional achy pain but denies flashes and floaters at this time.”
If the patient had cancerous lesions or an extensive history, include all of it- the dates of diagnoses, previous procedures, everything. Notes for patients with thyroid conditions should also include the micrograms of any pertinent medications they take and any dry eye symptoms.
Conclusion Whereas most of ophthalmology deals with the eye and the visual pathway, plastics deals more with the area surrounding the eye. Ailments of the lids can cause drooping, trouble keeping the eye open or trouble closing them. When the eyes have trouble closing all of the way, whether from the lids not functioning properly or because the eye is bulging, dryness and cornea problems can arise. This can cause excessive tearing, pain, and discomfort. Lumps, bumps, and lesions can be as benign as a clogged gland or as dangerous as cancer, and plastics physicians remove them all.
SECTION III DIAGNOSTIC TESTING
Chapter 11
VISUAL FIELDS Visual fields are to ophthalmology as Mondays are to the workweek nobody wants to go through with them but they’re unfortunately necessary. Patients hate them because they’re taxing and techs hate them because each test can take 20+ minutes of staring at someone’s constantly shifting eye and repeatedly telling them to “focus on the center light” a bazillion times. If you’re antisocial or a vampire, the visual field room is the place for you. No matter if you are on an Octopus, Humphrey, or the modern-day dinosaur which we call the Goldmann, visual fields require darkness. With one eye patched, patients are told to fixate at one point and click a button whenever they see a light flash in their field of vision. Once the first eye, typically the right, has completed the test, that eye is then occluded so the fun can begin all over again on the opposite eye. In theory, this test sounds simple, but test takers tend to hate it. Remaining focused on a single dot for more than a moment is near impossible for some, so patients tend to let their eyes wander, messing up test results. Lucky for the visual field technician, computerized machines have an internal camera that fixates on the patient’s eye so we can see when focus or gaze is lost. Nowadays, the visual field machines do most of the work for us, so we don’t have to manually move the light source, or stimulus, around. Our job
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is to patch, observe, switch eyes and save or print the results but our biggest responsibility is to instruct the patient properly throughout the entire process. A well-instructed test taker is going to perform better than someone who just gets the gist of things. When giving instructions, just like when instilling eye drops, it is best to go over everything, whether it is the patient’s first test of their 100th. Explain that they’ll be taking a test to measure their field of vision and that each eye is tested separately, so one eye will be patched during their exam (with the exception of an Esterman driving field).
PERIMETRY Earlier on, we looked at confrontation fields which give us a gross look at a person’s visual field (VF). Patients with glaucoma, a history of stroke, brain tumors and injuries, ptosis or field loss with no identifiable cause can be given a formal visual field test to find and document the loss. Though there are many types of perimetry (or visual field) tests, they can be broken down into two main forms of testing: kinetic and static [36].
Kinetic You may have to answer a question or two about kinetic VFs for an exam, but, unless you work for a low vision specialist or other specialty eyecare setting, you’ll probably never use kinetic perimetry. In this type of field testing, the tester manually moves a stimulus for the patient, from areas of no sight to where the patient can see it. The tangent screen test, where a tester moves a white stimulus over a black screen, is a simple way to check for defects that maybe confrontation fields may miss [37]. Before the production of all the static VF machines we have today, Goldmann visual fields were one of the best ways to record a person’s field of vision. A technician sits behind a large half globe and manually moves a light around the backside of the patient so that it shines on the inner part of the
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testing globe. The patient is given a clicker and told to press the button every time they see the spot of light, all the while staring at the center of the machine. When the patient clicks the button, the tech marks a sheet of paper held up to the backside of the machine at the exact location of when the patient saw the stimulus. When the test is done, the technician will then connect all of the dots to reveal the area in which the patient has sight. The test will often use stimuli of varying brightness or size to map out the island of sight. This test is done monocularly, or with one eye patched, in most cases. Driving fields are the exception, as both eyes need to be open to determine whether or not the totality of one’s visual field meets the minimum standards for safe driving. Goldmann VFs are often a great option for those with cognitive issues or malingerers, as the tech can work at the pace that is just right for the patient.
Static Static perimetry is the most common way to check visual fields in modern optometry and ophthalmology. The difference between kinetic and static tests is that, instead of the stimulus moving from an unseen area to a sighted one, the machine produces seemingly random lit spots in the testing bowl. Static fields, like the Humphrey or Octopus, do most of the work for the tech; all we have to do is determine the lens power needed for the test taker and make sure they are looking at the fixation point the whole time. Newer model Humphrey machines have a “liquid lens” that even forms into the proper lens prescription for the eye, eliminating the usage of loose lenses. Since many offices don’t have the funds for new technology as soon as it comes out, they often elect to keep what they have (if it ain’t broke, don’t fix it) so instead of going over machine-specific information, we’ll look at the three components of the test: lens selection, instruction and the test itself.
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Lenses After you turn the machine on and have entered your patient’s information (name, date of birth and medical record number if they are not already in the system from a previous exam), you will be asked to enter their latest refraction information. If you have their latest manifest or finalized Rx, you can enter this, otherwise, their current glasses prescription works. Because the distance of the test is closer than optical infinity (20 feet), you’ll have to adjust the script for near. Luckily, when you compute the distance Rx into the system, the machine will calculate the corrected lenses that you need. Once you have said lenses in your hands, place them in the lens holder. This little arm that sticks up from the inside of the globe can hold up to two lenses, one for sphere and one for cylinder. Spherical lenses go in the slot closest to the patient’s eye and cylindrical lenses in the slot further from the face. Angle the cyl lenses so that the dashes reflect the axis of the patient’s astigmatism (up and down for 90 degrees, left and right for 180, etc.).
Instruction Once the machine is set up, you’ll need to tell the patient how the test works, even if they’ve had it before (if a patient can forget how to hold an occluder, they can forget how to do a field test). Since this test is performed one eye at a time, you’ll need to patch whichever eye isn’t being tested. Let your patient know this and tell them that you’ll test the other eye directly afterward. When patching an eye, make sure that the eye is completely occluded. Stick on patches do the trick, but if using a patch on a string, place a folded tissue between the eye and the patch to block out all outside light. Give the patient the clicker. Instruct them to click the button whenever they see a spot of light pop up anywhere in the globe around them. Before
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the test begins, you can track the patient’s gaze. This is the only time they will be allowed to look away from the central fixation point. Underneath the center spot is four smaller lights arranged in a diamond. For a few moments, the machine will perform a mini test and will give you a pop up once it is time for the real test to start. At this time, you will make them look at the center fixation light. In the center of the visual field bowl is a lighted spot, usually with a yellowish tint to it. This is your patient’s fixation point. Tell your patient to keep their focus on that specific spot for the duration of the test. Really drive it home. If the test taker loses focus too often and breaks their gaze, it’ll screw up the test. In fact, tell them that. Let them know that you will have to repeat the test all over again if they continually look away from the fixation point. This portion of the test can take about seven to fifteen minutes per eye, which, to the patient’s credit, feels like an eternity when you’re doing nothing but staring at a small circle for that long. Telling them that they’ll have to do it all again will usually prime them into taking the test properly. Remember to observe your patient for the duration of the test. It is pretty easy for the patient to lose focus or even doze off in the machine, causing faulty results. As the patient is gazing at the fixation point, many small dots of light of varying size and brightness will be flickering around them. The test taker is to click the button every time they miss a light other than the fixation point. You can tell them not to worry if they think they missed a light, because it may appear again. Although you don’t have to tell the patient, you can let them know that you have a camera pointed at their eye which lets you know when they look away from the fixation light. This may help them maintain their gaze, but it might not. Whether or not you tell your patient that you’re watching them (you don’t want to make them too nervous), you should always keep them in the know about how much time is left for the test. Coach them through,
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letting them know when they’ve hit around the halfway point and when they are almost finished. When the test is finished, let them sit back and rest for a moment while you get the machine ready to test the other eye. If the patient had too many fixation losses, false negatives or false positives, you may have to repeat the test on the eye. Otherwise, patch the eye you just tested and repeat the steps for the other eye.
RESULTS In a healthy, normal visual field, the result will look mostly clear with a small, offset dark spot that correlates with the optic nerve – this is the physiologic blind spot and is a normal finding. The VF results for someone with field limiting pathology will look different depending on the ailment, revealing dark spots that represent areas where the patient cannot see. These are called scotomas. By looking at the test results, you can often tell what your patient has if you know what to look for. Doctors are seldom in the room for visual fields and rely on the technician to be in complete control while administering it. Educating the patient as to when to respond and when not to respond is imperative. Several patients will click their button upon hearing the sound of the machine and not necessarily when they are seeing a stimulus.
Peripheral Field Loss Peripheral field loss is one of the most common results in perimetry. Glaucoma causes decreased peripheral vision that slowly increases over time. This is caused by damage to the optic nerve and, therefore, other optic nerve issues may cause similar defects. Additionally, if a trial lens was used but not placed close enough to the patient’s eye, the rim can cause a peripheral defect or artifact.
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Glaucomatous patients may also have related defects, such as nasal step or a Bjerrum scotoma, which is a comet-shaped defect that stems out from the physiologic blind spot.
VISUAL FIELD DEFECTS 1) Total monocular (left) 1) defect Total monocular (left) defect
2) Left nasal hemianopia 2) Left nasal hemianopia
3) Bipolar hemianopia 3) Bipolar hemianopia
4) Right homonymous 4) hemianopia Right homonymous hemianopia
5) Left homonymous with 5) hemianopia Left homonymous macular sparing hemianopia with macular sparing
Figure 9. Visual field defects.
6) Left pie in the sky defect 6) Left pie in the sky defect
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Homonymous vs Heteronymous Some defects only affect one eye but others affect both. Defects that refer to the same side in both eyes, as in a right-sided cut in both the right and left eyes (temporal right eye and nasal left eye) are homonymous. Should a person have a defect that encompasses the temporal field in both eyes, it is a heteronymous defect. The specifics of the visual field defect’s location routes directly back to where in the visual pathway an injury or lesion is located.
Quadrantanopia Looking at the word, you could probably guess that a quadrantanopia is when a quadrant of one’s visual field is problematic. And you’d be right. A superior homonymous quadrantanopia (either right or left quadrant in both eyes) is sometimes called a “pie in the sky” defect because a pieshaped portion of their upper vision is missing. Conversely, an inferior homonymous quadrantanopia (either the right or left quadrant in the bottom half of the field in both eyes) is often referred to as “pie on the floor” for the same reason. Both defects stem from a lesion along the visual pathway after a part of the brain called the geniculate nucleus but after the optic chiasm.
Hemianopias A hemianopia is when an entire half of a visual field is missing. Hemianopias “respect” the vertical axis, meaning either the right side or left side of someone’s field is missing – no the top or bottom half. With bitemporal hemianopia, where the temporal field in both eyes is missing, the point of vision loss stems from the optic chiasm- the point where the visual pathway meets. Homonymous hemianopias, or the defect of either both right fields or both left fields, stems from the optic tract. If the left
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field is gone, the problem is caused by the right tract, but if the right is out, the trouble is in the left tract.
Macular Sparing Some patients will have a hemianopia or quadrantanopia, but their visual field cut does not include the very center. This is called macular sparing, which means that, even though blood flow may not be reaching the entire eye (causing a VF defect), the blood flow to the macula is still intact. This is a sign that a person has damage to only one side of their visual cortex, which could be from a stroke.
Monocular Defects A defect that affects only one eye is caused by either retina or optic nerve issues. While retinal pathology can cause partial defects to complete loss of vision, most total vision loss is caused by optic nerve damage. Optic neuritis, neuropathy, papilledema, and glaucoma can all cause complete vision loss in an eye, so take special care when checking fields in a monocular patient’s good eye to prevent any further vision loss. Giant cell arteritis can cause complete monocular vision loss, as blood flow to the eyes can get restricted. Though this vision loss often presents as monocular at first, the other eye can go blind quickly afterward if not treated promptly. While some vision loss may be reversible, damage to the optic nerve, like that caused by severed blood flow, can cause irreversible loss. Have your patient place their chin in the chin rest, forehead forward against the headrest. If you’re using a Spectralis, you can let your patient know they can blink as they would normally, but certain other machines may require your patient to hold all blinking until the scan is complete. If the machine you are using has the capability to use previous scans as a reference point, like how the Spec lets you click “Follow-Up” and finds the exact place the scan was performed last time, use it. This way the
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doctor can more easily compare your current scan to everyone they have had leading up to this point. Remember to always look in the machine’s database for an existing chart for your patient before entering them in as a new patient. Whether it’s a visual field or photo, having all of their results in the correct chart is insanely correct. It goes without saying, but always try to get the best shots that you can without rushing. If the image looks grainy, your patient’s eye might be dry and giving them an artificial tear might help clear up the picture. If they keep moving, someone may have to come over and help hold their head still. Patients that have droopy lids or fall asleep in the machine will probably have to have their lids held open. A cotton-tipped swab with a six-inch stick works great for this if you hold the cotton part at the lid crease and gently roll the lid back. Some cataracts or corneal scars prevent even the best ophthalmic photographers from getting a scan. Just remember to breathe, try your best, ask for help when you need it and let the doctor know if you just can’t image the eye for whatever reason.
Chapter 12
IMAGING To me, imaging the eye is one of the coolest parts of ophthalmology. Whereas refractions and visual acuities are more subjective, OCTs and photos document objective pathology. Reading about a diagnosis and seeing a diseased retina or optic nerve are two completely different things; it’s kind of like “putting a name to a face” but for ocular dystrophies.
OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography, or OCT, is the gold standard in optical imaging. OCTs pack in a lot of info, so much so that there is a special certification that techs and ophthalmic photographers can take just for OCTs and OCT-A. Because of this, we’ll only cover the basics of the test, how to instruct your patient and what to look for in a scan. There are a few books out about OCTs, including Optical Coherence Tomography and OCT Angiography by Darrin Landry and Dr. Amir Kashani (Bryson Taylor), which is a great reference guide full of full-color scans. There are many different types of machines that offices use for OCTs, but they all are either time-domain or spectral-domain. Time-domain is the original type of OCT scan. This OCT images about 400 scans per second
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at every 30°³⁸. Advances in technology led to spectral-domain OCTs. These machines can image about 40,000 shots per second and don’t skip every 30° as the domain models do. Additionally, the resolution on the spectral machines can be as clear as 3 microns, where time domains might only scan in 15-micron resolution. Both are super tiny but the spectraldomain is still about 3-5 times more precise and physicians are less likely to miss pockets of fluid or pathology. OCT machines give us the opportunity to capture autofluorescence imaging. Fundus autofluorescence, or AF for short, gives us a good look at the retinal pigment epithelium layer by using bright lights. The longer you image the retina, the better the image resolution becomes. The lights used for this study can be excruciatingly bright, so give your patient ample heads up and allow them to take breaks as needed. Sometimes, your patient cannot handle the test for more than a few seconds, so get what you can and try your best but keep their comfort in mind.
Instructions Once you have found your patient’s existing account in the machine (or you have entered their info for new patients) you can get them ready for their scan. Wipe down the head and chin rest and explain how the test will work in layman’s terms. You can say something like: “This scan will give the doctor a look at the different layers that make up the back of the eye that they might not be able to see otherwise. Inside the machine, you’ll see a blue light/cross [or green star or whichever focusing point your machine has]. Keep focusing on that target, even if I move it around. I’ll take some pictures of the right eye, then do the same thing over again for the left.”
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FUNDUS PHOTOGRAPHY Fundus photos are great for documenting the progression of disease and/or treatments. Some pictures are taken as flat, 2D shots and others are taken in pairs and render a 3D image when using a stereoviewer. There are so many different kinds of cameras, from wide-view Optos to digital Canons and even old-school film cameras. Because every single camera has its own protocols that require a whole instruction manual to use them, we’ll discuss the bigger aspects of ophthalmic photography that carry over from machine to machine. For any image or photograph that isn’t aiming to document the anterior chamber, a dilated eye is better than an undilated one. Some digital cameras do not require dilation but any photo of the retina or optic nerve will come out better if the patient was given drops. Most cameras require dilation for two major reasons. First, for pictures that don’t require a flash, when the pupil is wide-open, the iris isn’t in the way to restrict the view from the fundus and makes for a cleaner shot. Second, for photos that require a flash, the flash is bright. Super bright. Without drops, your patient’s pupil will constrict immediately, making the pictures nearly impossible. If a patient cannot be given dilating drops, talk with your physician to see what photographic options they want to go forward with.
Instruction Similar to the instructions you would give an OCT patient, inform your patient of what the test is and why you are taking these pictures. Give them a heads up that there will be bright flashes of light, just like a regular camera, but it’ll appear brighter because it is directly in front of their eye and their pupil won’t be filtering any of it out. Have them place their chin in, forehead forward and adjust their positioning as needed throughout the picture taking process.
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Since there are some harsh, bright lights coming your patient’s way, they might flinch, squint, or close their eyes unintentionally. In situations like this, you might want to call another tech over to help hold lids or keep the patient’s head against the headrest. This will prevent them from pulling away or shifting too much.
Stereo Photos Stereo photography uses multiple images to render a 3D picture of the macula, optic nerve or any lesions in the eye. Some newer cameras have an option to automatically take two side-by-side images for you but the vast majority do not. To take stereo photos, take a picture of the area you want to document and then slightly move the camera (or the patient’s head, if this is easier) to offset the first image. When viewing these pictures, a stereoviewer can be held up to your eyes to merge two images together. The viewer uses internal mirrors that act as prisms to fuse two photos placed beside each other into one. If you don’t have a stereoviewer, quickly clicking back and forth between the pictures on a computer has a similar, though not perfect, effect.
Fluorescein Angiography Fluorescein angiograms (FAs) are timed fundus photos that document the release and leakage of fluorescein dye. The dye is administered through an IV in the arm (or hand, depending on the patient) and, after pictures without the dye have been taken, the photographer will take images with the red-free filter during five stages [39]. The IV is set up through an artery so that the dye circulates through to the eye just remember arteries arrive to the eye and veins drain from them. Pictures are taken as they are given the medication, otherwise known as the push, and pictures continue for 10-20 seconds to document choroidal
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filling. More pictures are taken at about 45-60 seconds, 5 minutes and again at 10. Office protocol may deem photos at 20 minutes necessary.
EXTERNAL AND CORNEAL PHOTOGRAPHY Photography involving the internal eye generally involves machines that have been designed specifically for that task. Some photographers and physicians elect to use digital cameras or even cell phone cameras for lesions or EOM disorders.
Slit Lamp Photography Pictures taken at the slit lamp are an excellent way to capture corneal defects and anything around the lids or lashes, like lesions. Slit lamp cameras are magnified to capture the details of a pinguecula or guttata but are not as magnified as a fundus camera. Much like traditional fundus photography, you’ll instruct your patient to keep their eye open (or closed for certain external shots) and you may need help holding lids. Slit lamp cameras can come as a standalone camera that resembles a biomicroscope or as an attachment that you can hook up to any slit lamp you have in the office. Since you’re a pro at maneuvering around the slight lamp by now, positioning your patient for their pictures should come naturally to you.
External Photography External photos are taken with a normal, everyday camera at different distances from the patient, depending on what part or function of the eye is being photographed. Just as they would with a slit lamp, doctors may ask for external pictures for lesions or masses. These typically call for less space between you and the patient and possibly even a specialty lens for
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magnification. Bulging eyes, drooping lids, and tropias afford you a little more of a buffer between you and your subject. These pictures tend to require more than just a single central gaze shot. You’ll more than likely need to have your patient look in nine different gaze positions: centrally, up, up and to the left, left, down and to the left, down, down and to the right, right, and up and to the right.
ANTERIOR IMAGING Many external and corneal imaging systems have been developed for determining the thickness of the cornea or the depth of the anterior chamber. Machines like these are often used for cornea, cataract, or glaucoma patients.
Anterior OCTs Anterior OCTs are similar to the posterior kind, except they image the front of the eye, including the cornea, lens, iris, and angles. These scans come in handy for both cornea and narrow-angle glaucoma patients.
Specular Endothelial Micrography Specular Endothelial Micrography gets even more detailed by photographing the corneal endothelium [40]. Contact models require a topical anesthetic and gently touch the eye. Carefully move the camera in and out to focus the hexagonal cells of the endothelium and grab your image. Noncontact models work a lot like the contact ones, but do not touch the eye. They don’t have as high a resolution, either. Doctors can use these cell counts to determine the health of the external cornea and they come in handy for cataract and dry eye patients.
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Topography Corneal topographers produce a 3-D map of the surface of the eye. Scars, ulcers, cuts, keratoconus and even typical astigmatism cause corneal irregularities and topographers are a great way to document them. Corneal topography can be done via standalone models or with travel versions that attach to slit lamps but the usability of them is roughly the same. Just as you would with any diagnostic test, input or find your patient’s information in the database or find them in the system if they’ve been imaged previously. Have your patient set their chin in the chin rest, forehead against the headrest. Instruct them to look at their target, whether it is the innermost ring or a picture depending on the machine’s set up, and line them up to where they need to be on your computer’s screen. Most topographers will provide you guidelines on the screen that assist in lining up the cornea for the best mapping. Across the cornea, you’ll see rings that will help render a 3-D image for the physician to read. Once you’ve taken your photo of the right eye, switch to the left and repeat the mapping process. The finished results resemble a geographic topographical map, where the blue represents the low points and works its way up through green, yellow and orange layers until the highest elevation, the red peaks. Topography is a very useful tool for general ophthalmologists and corneal specialists when looking at the front of the eye, including cataracts. Follow your office’s protocol for cataract consultations and include this test as required.
IOL Calcs Cataract surgery often requires a great deal of testing prior to the procedure to ensure the best possible outcome for the patient. Intraocular lens calculations, or IOL calcs for short, are one of these tests and the Zeiss IOLMaster is one of the most popular machines for this measurement.
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Considered the “gold standard” in optical biometry, the IOLMaster is a form of Partial Coherence Interferometer. Note that there are methods other than this to gauge lens measurements but is this the most used in ophthalmology. This machine is great in that it has a plethora of IOL formulas like Halladay II already programed into the machine, so no additional math is required [41]. Using the machine is relatively simple. As we’ve told our patients millions of times by now, they first need to bring their chins in and foreheads forward into their respective rests. Once in, the machine will run a series of numbers by measuring wavelengths through media of the eye – the cornea, lens, vitreous and overall all axial length. This data gives the surgeon a better idea of what lens to pull for the lens replacement.
A-SCANS & B-SCANS Different from photography, ultrasonography, or ophthalmic ultrasound, gives physicians an idea of what the structure of the eye looks like as a whole. These scans, both A- and B-, take the entire eye from cornea to optic nerve and render either a 1D or 2D image [42].
Figure 10. A-scan. 1) The probe. 2) First amplitude spike. This corresponds to the exterior cornea. 3) Spike for inner cornea. 4) Spike for anterior lens. 5) Spike for posterior lens. 6) Spike for retina. 7) Spike for posterior sclera. 8 & 9) Spike for the orbital tissue.
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A-scans provide us with a one-dimensional graph, mapping out peaks and valleys that represent the various media of the eye. The peaks of the zigzag line show you where the change in media occurs, like the posterior part of the anterior chamber or the back of the eye. A-scans are good for telling us how big the eye is or how the shape of the eye looks. B-scans, on the other hand, are 2D ultrasounds of the eye. Before the invention of 3D ultrasounds that pregnant women get to see the facial features of their babies while they’re still in utero, 2D ultrasounds gave us a vague idea of what babies looked like. B-scans are the eye equivalent of this. Instead of the normal chin-in-forehead-foreword setup, patients sit or recline back and have their eye imaged with a probe that slides around the lids or directly on the surface of the eye. The surface that is being touched by the wand, whether it is the front of the eye, sclera or lid, is projected on the screen at the left-hand side and the image is projected outward to the right of the screen. These ultrasounds let us see masses, retinal detachments, hemorrhages and ocular structure in situations when we would not be able to normally see them through photography or dilation. B-scans are especially useful for those with dense cataracts or bad bleeds.
Figure 11. B-scan. This image represents a scan where the probe is touching the cornea (left). Immediately next to the probe is the anterior chamber and lens. The dark center of the scan is the vitreous media and ends at the posterior retina and sclera. A slight darkening of the image behind the eye (right) represents the optic nerve.
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Patients receiving a B-scan will need to be prepped with an ocular anesthetic and a lubricant (the kind that doctors use for gonioscopy works well here) if you are touching the actual eyeball. Scans taken with the probe on the skin around the eye require ultrasound gel. Instruct your patient as to where to look for the shots you need and inform them that you will be taking images of the eye while it is open, if applicable. Once you’ve found the area that you want to document, you just need to click a button to capture it. When a patient is focused on their eye, their pupil is likely to constrict, potentially causing poor imaging. Distracted patients aren’t as hyperfocused and dilate for better scans. Tapping their feet or thinking of something calming can help them worry less so you can get your job done. When remembering the order of imaging for ocular ultrasound, think of the acronym SNIT: Superior, Nasal, Inferior and Temporal. This is the order in which you should take your scans so that you can always know which picture is of what angle without having to think about it. It is important to note that the marker is directed properly for every scan so that it doesn’t invert the picture. For superior shots, the marker is on the lower eye pointing upward with the marker pointed toward the nose. Nasal scans point from the temple to the nose with the marker at 12:00, inferior scans point downward from the top of the eye, marker in toward the nose and temporal shots are taken again with the marker at 12:00 but this time with the wand touching the nasal sclera, pointing out toward the ear.
Conclusion Modern technology has made documenting the eyes and their pathology easy, and honestly, kind of fun. Cameras take pictures externally and inside of the eye while scans can image the different layers of the cornea, anterior chamber, and retina. The machines we use are constantly
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evolving as the tech gets better but a camera with actual film still does the trick. Patient comfort is key and as long as they can remember to keep their eyes open, chins in and foreheads forward, you’ll be good.
Chapter 13
OPTICS If you’re like most technicians, reading glasses may be difficult. Especially ones with prism. Lots of offices have automated lensmeters and loads of techs have no idea of how to work a manual one. Many offices also have opticians who can read a prescription for you when it is difficult. The goal, however, is to not need anyone to perform this task for you. During downtime, opticians and techs who can neutralize lenses normally don’t care, but when the schedule is busy or they have their own patients, reading scripts for other people can become burdensome. This is why, even if you abhor reading lenses, you have to learn how to. Even if your office uses an automated lensmeter, knowing your way around a manual is ideal for two main reasons: 1) you’ll need to know your stuff if you want to get certified (especially for the COT) and 2) people don’t always use the automatic machine correctly. Readings on the automatic machines aren’t going to be right if the user isn’t correctly holding the glasses in the reader or they aren’t accounting for a progressive or prism. The same goes for a manual lensmeter, but, when using one of those, we can physically see that something looks odd, like a prism displacement, and we’re more likely to catch and document it.
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The term “Lensometer” is actually a copyrighted term like “Kleenex” or “Xerox”. Lensmeters is the generic term for the machine. The different levels of certification from JCAHPO and the ABO require varying amounts of knowledge on light wavelengths, reflection, and refraction, there are literally textbooks filled with these theories and laws and, truthfully, you don’t really need to remember a great deal of that stuff as a tech. Not that knowing about light isn’t beneficial it certainly can be but, as I am focusing on how to be an optimal tech in this book, so I’ll leave that information to the opticians for now. What’s important is that you know your way around a pair of glasses.
GLASSES Virtually every feature on a set of glasses can alter the effectiveness of the prescription if they are not fitted properly. If the temples are too loose, the frame slips downward. If the face form is off, this alters the curvature of the lenses. If the nose pads are too close together, your presbyopic patient might end up looking through their intermediate script instead of the distance portion. If the lenses are too far away from the face, the patient is over-plussing themselves. If the glasses were fit with the wrong PD measurement, the glasses will have induced base-in or base-out prism. As techs, we don’t generally have to fit glasses (unless optical is shortstaffed for the day) but knowing all of this is major if your patient is returning for a prescription check. It is not uncommon for a patient to come in for an Rx check when the glasses were just made wrong. Similarly, there are times when patients think their glasses were made wrong when it was really a script error. Glasses are tricky and they require us to know enough about them to figure out where the problem lies.
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Figure 12. Anatomy of Glasses: 1 Frame front. 2 Hinge. 3 Bridge. 4 Temple. 5 Ear piece. 6 Lens. 7 Lens height (B measurement). 8 Lens width (A measurement).
More often than not, your patient is not going to have prescribed prism, so you won’t have to worry about it that much. Usually, patients under 45 will have easy to read single vision prescriptions and beginning at age 45, patients may have progressives or lined bifocals. The easiest glasses to read by far are single vision spherical lenses, which is most common for young kids and the first pair of glasses for some adults. This is because astigmatism correction, or cylinder, can be hard to get used to, at least at first, so prescribing doctors are more careful when prescribing it. Under the lensmeter, all of your lines (skinny and fat or triple and single) will line up clearly when you hit the right prescribed amount of sphere. Easy. Astigmatic single vision is not much more difficult. For purposes of uniformity, we’re just going to look into reading in plus cylinder form. When reading astigmatic lenses, it’s important to find the sphere first. Until you get the hang of a manual lensmeter, turn the sphere drum way more minus than you think your lens needs. When your lens is in the machine and you’re ready to neutralize, begin slowly turning the sphere dial to add more plus. When the first line(s) comes into focus it represents is your spherical power. If they look fat instead of skinny, turn the axis wheel by 90° so they appear skinny. Next, adjust your axis dial in the back so that your triple skinny lines are clear and unbroken. The number the notch on the machine is pointing at is your axis. After you’ve noted those two values, turn your sphere drum again, adding more plus until you have a clear fat line or set of lines. Subtract this new reading on the sphere drum from your original and you have your cylinder.
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Example: On the first reading, the sphere drum says -5.00. The axis dial reveals the skinny lines at 90°. You add more plus and now your second sphere reading says -2.00. The difference between -5.00 and -2.00 is +3.00. Your patient’s prescription for that lens would read as -5.00 +3.00 x090. For many, math is difficult. If you just remember how number lines work, you’ll be able to do this. Leave the algebra for the opticians. Also, of note, axes go from 001 to 180. There is no 0 axis and the proper way to note the axis is with three digits, like 009 or 020 instead of 9 or 20. Lined bifocals are easy once you get this concept down. Read above the bifocal segment, checking your sphere, axis, and cylinder, then measure the sphere of the bifocal segment. The cyl and axis won’t change for the bifocal, so there is no need to re-read it. That additional sphere power is your “add”. Progressives are slightly harder. Because there is no visible line to show you where the bifocal begins, figuring out where to measure takes a little more effort. Opticians sometimes have a special light attached to a magnifier that helps them find the tiny laser etchings on progressive lenses, but, if your eyesight is good enough, you can hold a lens up to a light source at the right angle and find it. The laser marking on progressive lenses reveals a lot of information. Firstly, the lenses have numbers etched on them this is your add power. Sometimes the lenses will have three digits, like 275, but other times it’s condensed down to two, like 27. Since all adds run in quarter diopters, dropping the last digit does not make any difference. Next, there are shapes and symbols inscribed on the lenses. The shapes and their placement determine the brand and design, much like a make and model of a car (Honda makes Civic, Varilux makes Physio). Lastly, where the markings, which are usually little circles, are placed is where the progressive was placed. This means that when the patient saw the optician, this is where they were fit for this particular lens so they can experience the best distance and near correction from it. Usually, this height corresponds with the center of your patient’s pupil. By using a special marking pen to dot those spots (or making a careful mental note of
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where those spots are) measure about 4 mm above those dots. This is where to measure for the distance portion of the lens. Since the ad is already laser engraved onto the lens, you don’t need to measure the bifocal part unless you can’t find the marking. Hint: The laser marking of the add power, whether two or three digits, is always on the temple side of the lens. There is very little exception to this rule (like maybe one or two out of hundreds of thousands of lenses) so if you see the add power on the nasal side of the lens, those glasses were probably made wrong.
Prism Prisms are hard to read but even harder to teach, so we’ll review the basics before delving into how to read them. Prism is added to prescriptions to treat double vision. To do this, prisms are a transparent medium that refracts light at a certain angle. How? Think about when the light comes through a window at certain times of day and it casts a rainbow into the room. The light from the sun is hitting the window (the medium) at a particular angle and the white light is being broken up into several colors of light that come together to form it. This is a prismatic effect. For a practical application, think about how when you put a straw into a glass of water and you look at it from different angles, the straw looks broken in half and disconnected from its other piece. The clear medium (the glass, water) is displacing the straw much like a prism lens would. Additional Roles Though our main job as assistants and technicians is to conduct the preliminary eye testing for our eye doctors, there will be times when we will have to call patients back with answers to their questions. Sometimes you may even have to man the phones for the front desk. You may even be responsible for checking patients in and out,
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scheduling patients and possibly pulling insurance information and benefits for them. In smaller offices, you may have been hired to be the tech and front desk receptionist. Each EMR is unique, so it is best to get precise instructions from your trainer or current receptionist for the ins and outs of navigating the system. No matter which medical records software you use, how you greet and treat the patient can be more important to how a patient perceives their eye exam than copay costs and wait time. Let’s suppose you are at a store. You’ve traveled out of your way and decide to spend your hard-earned money at this particular shop and now the sales associate decides she wants to be rude to you. You ask a question, she rolls her eyes. You clarify her answer and she makes you feel dumb. There is a great chance that you won’t be making your purchase after all and you might even consider never going back to this place. Now, we aren’t cashiers or sales associates, but we are, however, an integral part of the exam and when we’re checking patients in, we’re also the front line. As such, how we conduct ourselves sets the tone for the next hour(s) that a patient will be in our office. That being said, there will always be patients with a negative attitude who we just won’t be able to please. It’s okay. Though we cannot necessarily improve their outlook, we can make it as hard as possible for them to find fault during their exam or prevent their experience from being any worse at the very least. The last thing you need is for someone to complain to your boss or doctor before the exam even begins. This courtesy, of course, extends past the front desk and exam rooms. Answering phones or returning patient calls is an important task, but it isn’t generally perceived as being a fun one. Eye problems are routine for us but can be scary for patients. Listen to them and answer them within the scope of your role as an assistant. Don’t offer medical advice or try to diagnose any issues. Offer a timeslot for a visit or refer them to the emergency department if need be. Be kind and supportive – you might know it’s just dryness or a normal floater but they might not. Put yourself in their shoes and treat them compassionately.
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Prisms help guide the eye to where it needs to see one single fused image with the other eye. If a person has an eye that is turned outward, that lens is going to have to get that eye to point back inward. When prescribed in glasses, prisms are either vertical (base-up or BU, base-down or BD), horizontal (base-in or BI, base-out or BO) or a combination of the two. If someone has vertical diplopia, base-up and base-down prism will be prescribed. If their vision is horizontal, they’ll need base-in or base-out.
Figure 13. Prism reference point: Laser etchings on the lens give important info about the PAL. The add power is shown temporally and the brand and model info is shown nasally.
Horizontal prisms compound each other while vertical negate. This just means that if the glasses lenses for both eyes read as 2 BU, the prism is a wash because both of the eyes will be looking up higher. If the right eye is 1 BU and the left eye has no prismatic correction, there is prism (1BU OD). In horizontal, it’s the opposite. If a prescription has 2 BI in each lens, there is 4 BI in total (2BI+2BI) but if the right lens has 2 BI while the left has 2 BO, they cancel each other out (and your patient is going to side-eye everything since their optical center is displaced). So, what all does base-up, down, left and right mean? Prisms have apices (pointy tops) and bases (thickest part). Light rays enter the prism and bend toward the base. This is all well and good, and important if you’re studying for your certification, but what you absolutely need to know is that the eye will veer to look toward the apex. If you have 3BO, your eye is going to turn inward while looking through that lens.
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Figure 14. A triangular prism, left, and pyramid, right. Light bends toward the base (bottom) and displaces images toward the apex (top).
When you put a pair of glasses in the lensmeter, as mentioned previously, you see a set of skinny and fat lines. When you don’t have any prism, your crosshairs line up in the center of the reticle. If one or more of your lenses are not centered, you then need to carefully check for prisms. Figure 15 illustrates some examples of what to look for.
Figure 15. Reticles: 1) A lens with no prismatic correction. 2) A lens with base-up prism. 3) A right lens with base-out prism. If this was the left lens, it would be baseout prism.
When the crosshairs are above center, you have base-up prism, when they’re below center, you have base-down. Horizontal is not as cut and dry. Sometimes if you may think you have prism when in reality, your patient just has an enormous pupillary distance (PD). Be sure that you are measuring the lens in the spot that they view from, especially in cases with people with super wide or super narrow PDs. If you find that there is a true decentration temporally, even after adjusting to where the glasses sit, you have base-out prism. If the crosshairs are offset nasally, you have base-in. This can be confusing at first because it is not as simple as saying prism to the left means base whatever because
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base-in and out prism is directly related to the nose and temple meaning the left and right lenses will read differently.
Glasses Adjustments You may go your entire career without ever having to adjust a frame, and if you don’t, fantastic. Again, leave that to the opticians, because if you break someone’s glasses, you might be held responsible for it and they are formally trained to do that kind of thing all day. If you are dispensing a new pair of glasses, leave the prism reference point marker on the lenses and have the patient try the glasses on. If their eye lines up to the reference point, no problems. If their eye is sitting too high or low, adjust the nose pads and, worst-case scenario, the temple hinges to bring the frame to the proper spot on their face. When lowering the frame, create more space between the nose pads or make the temple hinges slightly wider. If the frame is too low or a returning patient is complaining that their spectacles keep slipping down their nose, bring the nose pads closer together and tighten the hinges inward. You can also make more of a curve on the earpiece of the temple to prevent further slippage. When a patient states that their distance vision is fine but has problems reading through their bifocal, the pantoscopic tilt may be off. This means that the bottom of the lens might not be as close to the cheek as it needs to be. By bending the temple hinge downward, you’re increasing the panto which resolves the issue in many cases. Occasionally, patients who have never worn progressives before have trouble getting used to the different channels and “swim” (distortion) of the lenses. This is called “PAL nonadapt”, which means they have trouble adapting to no-line bifocals and may have to have their glasses remade into a lined bifocal. Glasses are amazing. They are fun, they are fashionable and many of us can’t see more than a few inches in front of my face without them, making them pretty useful. If you’re uncomfortable adjusting frames, let optical handle it but all techs should at least know the basics of lensometry.
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The practice you work for now may only use automated lensmeters, but the next office you go to may not have any.
CONTACT LENSES Contact lens fitters are a blend of teching and opticianry. Like opticianry, there is a whole other certification for lens dispensers with a multitude of textbooks and videos on fitting, so I’ll just review the basics. When we refract with a phoropter, we’re homing in on a glasses prescription. Glasses sit about an inch or so from the eye this is space between the eye and lens is called the vertex distance. The further from the eye the lens sits, the more plus (less minus) the lens appears. Contacts sit on the eye itself, creating less vertex distance. This means more minus less plus if your patient is more than +/- 3.50, you need to adjust your prescription. Rigid gas permeable lenses are typically only seen with older patients who have been wearing contacts prior to the invention off soft lenses and those with keratoconus. When refracting patients who wear RGPs, it is best that they discontinue wearing their lenses 48 hours before their appointment. Another thing to consider when fitting lenses is the astigmatism correction. Generally, if your patient has less than +0.50 cylinder, it can be dropped altogether, but it is always best to adjust the sphere by halving the cyl and adding that result to the spherical correction. This is referred to as “adjusted cylinder power” or spherical equivalent. Adjusted cyl works best if their astigmatism is +0.50 or +0.75. If a person’s cyl is over +1.00, it may be best to fit them into a toric lens. Many companies now offer lenses
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with astigmatism correction with rounded axes but for difficult fits, custom lenses can always be fabricated. Contact lenses hug the cornea so the steepness, or base curve, and diameter measurements are extremely important when fitting. Lenses that are too loose will move around too much and lenses that are too tight can cut off oxygen flow. Generally speaking, the steeper the lens, the lower its diameter and vice versa. Soft lenses come in a number of set measurements per brand and model. The perfect diameter is generally 2 mm more than the horizontal visual iris diameter (HVID for short) and deciding on whether to choose a flat, medium, or steep base curve is dependent upon the patient’s K values [44]. A good lens fit is measured both subjectively and objectively. First and foremost, a patient’s comfort is a good indicator of proper fit. Through the slit lamp, the fitter should make sure that there are no air bubbles and that the lens overlaps the limbus by 1mm all around. Have the patient blink in primary gaze and up gaze; a good lens fit should yield a 0.25-0.5 mm movement while the patient is looking centrally and 0.5-1.25 mm movement when looking upward [44]. Fit is a very important part of getting the CL prescription right, but it means nothing if the patient is wearing their lenses inside-out. Contacts are bowl-shaped so there are two easy ways to see if they are inside out or not. First, if you look at the lens and it’s rounded, the lens is okay but if the edges splay outward like the top of a vase, it is inside-out and needs to get flipped. A second way of telling if the lens is good or not is to do the taco test [43]. With the lens in between your thumb and forefinger, gently squeeze the lens. When a lens is oriented properly, it will resemble a taco shell, otherwise, it won’t bend right and the edges will splay out, making for a taco disaster. After manhandling a contact, always clean it before inserting it into a patient’s eye. Lenses may be uncomfortable immediately after insertion, especially for first-time CL users or for those who are trying out a new brand or lens design, but inside out lenses are very irritating. Patients may experience redness, excessive tearing, and blur when a lens is flipped. If a patient is
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complaining of these things after inserting their lens, have them take it out and make sure it is not flipped before alerting the doctor.
Conclusion Some eyes are too long and some are too short but we can use corrective lenses to help with refractive errors that this may cause. The placement of the lens itself is a big part of how the patient sees from them and therefore fit matters. Base curves and diameters are to contacts as pantoscopic tilt and vertex distance are to glasses, though BCs matter in glasses lens production as well. Prisms can help fuse two images together for those with double vision and the prism reference point is essential for reading progressives.
CONCLUSION Healthcare is one of the most altruistic fields of work in the world. Taking part in the care of another person as an ophthalmic technician at the front lines of eyecare can contribute meaningfully to the patient’s health and wellbeing and thereby be very rewarding. Not every patient is sick or exciting, but that’s a good thing. Healthy patients are what we want. But there will be times when you catch that visual field defect that prompts further testing or find that APD that leads to a diagnosis. Being a diligent tech can mean spotting something that a doctor can treat and, in turn, improve that person’s quality of life. We aren’t doctors and we aren’t nurses. We aren’t curing cancer or performing open-heart surgeries. We are, however, a very important piece of the healthcare puzzle. Not everyone has the stomach to work with eyes and it takes a special type of person to do all that we do. You’re here because you can do it. The manager and doctors who hired you know this – that’s why they hired you. No one expects you to know every little thing about the human eye when you first start out. There are plenty of techs who know nothing more than the basics, and that’s perfectly fine. Hopefully, this book has given you some of those basic principles that you can take to work with you so you can go in and assist in a person’s eye exam.
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Now that you know the fundamentals of eyecare, you can go on to explore more and be the best assistant you can be. Our job is to be knowledgeable, helpful, and compassionate, which extends beyond how we treat our patients to how we work with fellow techs and even ourselves. I wish you luck with your future optometric and ophthalmic endeavors and hope you continue to gain knowledge and experience throughout your career. Oh, and remember to turn your lensmeter off so the bulb doesn’t burn out.
APPENDICES APPENDIX A: EQUIPMENT AND INSTRUMENTS Assistants and technicians in our field would not be able to do all that we do without the numerous instruments, lenses, and machines of eyecare. There are seemingly thousands of instruments that can be used in an infinite amount of tray setups for surgical procedures – both in-house and outpatient – and there are a good deal of machines within the office that require proper care. In this chapter, we’ll go over some of the instruments that you are likely to see in surgical assisting, how to maintain the various pieces of equipment in the office and the differences between the terms clean, sterile and aseptic.
Handhelds In optometry and ophthalmology, there are three handheld tools that you may be asked to use or take care of for your doctors. The retinoscope, ophthalmoscope, and transilluminator are all lighted attachments that hook up to a battery-powered base.
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(a)
(b)
(c)
Figure 16. Handhelds. (a) Retinoscope. (b) Ophthalmoscope. (c) Transilluminator.
Retinoscopes are used by techs and physicians alike to streak patients for refractive errors. These are the long but wide lights that have an open window on one side and a peephole on the other. For more information about retinoscopy, see the Retinoscopy section on page 37. Ophthalmoscopes are the squatty, fat lights with a small window on the front with an eye hole on the back. The dial on the front changes the size, color and shape of the light and the larger dial on either side helps focus the magnification of the eyepiece. This handheld device is referred to as the direct ophthalmoscope while the headpiece that physicians wear for fundus exams is called the indirect ophthalmoscope, or simply the indirect for short. The transilluminator is the long skinny light that bends at the base. This bright light is good for any sort of brief external exam and is great for checking pupillary reflexes (see Swing Light Test on pages 23). Some optometrists use these instruments or penlights to illuminate the anterior chamber from the temporal side to quickly check the steepness of a patient’s angles. While we’re on the subject, make sure that all of the equipment in the office is in working order (including computer systems and printers) before the doctor steps foot into the room. Unless you want to enrage your doc, make sure that every room is stocked with drops, lenses, alcohol wipes, tissues, and everything else that you think your doctor may need.
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All of these lights unscrew and come apart to replace the light bulb inside and to change out the battery when it dies. Make sure to plop these guys back into their charging bases once you are done using them and throw them into the charger if you see the doctor left them out so that they last longer. A dying light is a surefire way to tick off even the calmest of doctors.
Instruments You can go from one practice to the next- or even one doctor to the next within the same practice- and see completely different instruments and setups. Depending on the procedure (and what your physician is most comfortable using for that particular job) you’ll most likely need to know at least some of the tools needed, in case you have to set up or assist in the future.
Speculums and Calipers First things first, the speculum is one of the most important pieces of equipment in the ophthalmic arsenal when it comes to procedures and surgeries. Retina physicians may need them for injections, cataract docs use them to hold the lids open, strabismus surgeons place them so they can work on the extraocular muscles and pretty much any other surgery that requires the eye to be open will require them. Speculums work by retracting the upper and lower lids back, preventing the eye from blinking. These instruments come in both adjustable and non-adjustable models and the use of either is completely up to physician preference. For quick procedures, like injections, rewetting drops may not be necessary, but your doctor may have you instill some in cases that are more than a few seconds long. Calipers are used to measure. Just as speculums do, they come in adjustable and non-adjustable forms and can be used in simple office injections to OR surgeries.
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Forceps As eyes are so small, they require tiny tools to pick up, grab and move its small parts. Forceps, or pick-ups, look similar to tweezers and are designed to hold tissue, materials or sutures. They come in toothed or nontoothed types and have different roles in the operating room. The toothed variety, like the Bishop Harmon or the sized forceps (0.12mm, 0.3mm, and 0.5mm) have little fang-like teeth that stick out from the tips of the tips that help grasp tissue. Non-toothed forceps, like jewelers, tissue forceps and tying forceps, are manufactured in either straight or curved types. While tissue forceps and tying forceps are usually reserved for the OR, jewelers are handy to have around the office for suture and foreign body removal. Hemostatic forceps look like scissors but are blunted with grooved jaws. These can be used to clamp tissue when the handles close or spread incisions when they are open. Scissors As in actual scissors, yes. In surgery, doctors use small scissors to cut tissue and sutures. Westcotts are about the size of nose hair clippers and are exceptionally sharp, as they are used to cut skin or muscle. Vannas are even tinier scissors with blades about half (or smaller) the size of Westcotts that are primarily used for snipping sutures. Needle Holders Needle holders, as their name implies, hold needles, specifically those attached to sutures. Sutures, which come in different gauges and materials like silk, Vicryl and gut, come attached to a small, curved needle. This is grasped by the needle holder to essentially sew tissues together. Also referred to as “needle drivers” or Castro-Viejos, needle holders come in both locking and non-locking varieties, where locking is good for normal stitching and non-locking is better for more delicate areas, like the cornea. Similar to many other instruments used in ophthalmology, they can have either straight or curved tips. Surgeons often prefer the holders with straight tips, so bear this in mind if passing off instruments.
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Syringes and Needles Whether in the OR or doing a retinal injection, you are likely to come across syringes and needles. The syringe itself is the tube and plunger that gets filled with injectable fluids while the needle refers to the metal tip that penetrates tissue to deliver said fluids. The syringes we use in ophthalmology come in four main sizes – 1cc (TB syringe), 3cc, 5cc, and 10cc. Needles come in a number of different gauges where the larger the number, the skinnier the needle. Larger needles, like 18g, are typically used as “fill” needles, meaning they are attached to the syringe to pull the medication from the vial. After the syringe is filled, the fill needle is discarded and replaced with a smaller needle, between 25g and 32g usually; the thinner needles make the injection more bearable for the patient. Needles come in different lengths so ask your doctor which size they will need should you ever have to prepare the procedure tray. Cautery More common in external procedures, a surgeon may use cautery to stop an incision from bleeding. Cautery equipment can be either disposable, monopolar or bipolar, with the disposable models ranging from high temperature to low temperature. The machine base that the cautery hooks up to lets the surgeon change the temperature, which, as a surgical assistant, you may need to adjust. If you ever have to navigate the machine, the dials are clearly labeled “Cut”, “COAG” and “Bipolar” for you. Get familiar with where these are on the machine so that you are immediately aware of their location when you are asked to increase their values. Procedure Specific Instruments Some of the most common in-office procedures in ophthalmology are those involving chalazia. Chalazion incisions and curettage require two pieces of equipment outside of the ones mentioned previously: the chalazion clamp and the curette. The clamp is placed around the chalazion for drainage and the curette is used by the doctor to scrape out the contents of it.
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A Kimura spatula is a tool used in cornea foreign body removals and ulcer culturing. Alcohol wells are needed for both corneal cross-linking and PRK. Cornea patients that need a conjunctival resection will require a Putterman clamp and anyone having cataract surgery will have a setup full of different spatulas, knives, and expressers.
Cleaning, Disinfecting and Sterilizing A huge aspect of instrument and equipment maintenance is making sure they are properly cleaned. Additionally, while some things can be sterilized, others can’t be, so it is important to know what cleaning agents to use on each piece of equipment. First, we should establish that there is a difference between the terms “clean”, “disinfected” and “sterile”. The term clean means that the instrument or area has been washed with a cleanser and water, but that’s it. Disinfected means that an object has been wiped with a disinfectant (often a 10% bleach or 3% hydrogen peroxide solution) to kill off bacteria; there are three levels of disinfecting chemicals to kill off various bacteria which are all very strong, so always use gloves when using these agents. Sterility, which is achieved through the use of an autoclave or gas treatment, kills off all organisms and spores that may invisibly live on an instrument [45]. This is different from being aseptic, where something is free of contaminants. These terms are often used interchangeably but mean two different things. Ophthalmic lenses can get damaged by chemical cleaners. Clean, dry lens cloths are the best way to clean phoropters and loose lenses. An important note: cleaning agents and chemicals must be fully dry before patient contact. Alcohol, peroxide, bleach, and other germicides can cause serious chemical burns to the eye. Any instrument used in a surgical procedure requires sterilization. Open tools can be placed on a sterile field and handled while wearing one-
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time use sterile gloves. If the field or tools are touched by a non-sterile surface, like an ungloved hand or a gloved hand that brushed against a nonsterile area (like your face or hair) then the area has been contaminated. All compromised instruments need to be removed from the surgical field and replaced with new, sterile ones. Injections and other minor procedures can be performed in partially sterile environments, like an exam room with a sterile tray setup. The room should be properly disinfected with disposable sanitizing wipes prior to setting up and any instruments that are to be used should be placed on a sterile field, or a single-use plastic-lined pad. Whether in a sterile environment or an aseptic one, always wear the proper attire – gloves (sterile for surgeries, non-sterile when acceptable), a mask, hair net (bonnet) and gown. If you are assisting in a minor treatment that does not require gowns, bonnets, and masks, it is important to not talk or open your mouth during injections, cutting or cauterization.
APPENDIX B: SURGICAL ASSISTING Surgery can be a big deal. As such, lots of behind-the-scenes work goes into the preparation of a procedure before it even starts. Not all procedures will require a full operating room setup and most can be performed using just local anesthesia. Before your patient can even enter the room for their surgery, there is paperwork to fill out and authorizations to obtain. Every procedure requires a consent for treatment that has to be explained to and signed by the patient. Legally and ethically, patients need to have a complete idea of what risks and benefits they could see post-operatively. Even the most basic treatments can risk infection. If your office wants to get paid for the procedure, an insurance authorization needs to be obtained ahead of time. For these, you may be responsible for sending information to the patient’s insurance company to make sure they are cleared for their treatment well in advance. On occasion, the insurance company may deem the treatment, be it a
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medication, surgery, or preliminary MRI, unnecessary and the ordering surgeon may need to perform what’s called a “peer-to-peer” to change their mind. This involves a phone call between the doctor and the insurance company directly, and it is best that, if it comes to this point, your doc has plenty of time to do this before the scheduled procedure. Any patient having cataract surgery needs to have the proper forms with the intraocular lens replacement’s measurements on it so the surgeon can implant the correct lens after removing the natural lens. Corneal transplants, muscle surgeries, and even punctal plug insertion all require precise measurements and one wrong number can be detrimental for the patient. Once all of the consents have been signed, the authorization has been granted, the surgery has been scheduled and the correct medication, lens or other important agents have been picked, it is time for the procedure. Ophthalmic procedures come in all shapes and sizes from intraocular injections in an exam room to cataract surgeries performed in a surgical suite or even the complete removal of the eye in an emergency center operating room. And virtually every treatment will need some sort of numbing agent. Proparacaine and tetracaine are commonly used drops for surface procedures, but excessive usage of them can lead to cornea damage. Aside from anesthetic drops, betadine is typically administered directly into the eye and/or applied to the surrounding area to clean it. Some in-office procedures may also require a pledget, or a sterile swab soaked in an anesthetic and held under an eyelid or a subconjunctival injection of lidocaine which is injected into the conjunctiva. External procedures might call for a lidocaine injection as well, but a topical lidobased cream may be easier on the patient in certain instances, like Botox injections or minor lid lesion removal. Once you’ve been fully trained to work in the OR setting, your main focus will be learning the procedure steps. This way, the doctor can count on you to have the next instrument or suture that they’ll need in hand without ever having to look up at you for it.
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Patching is a crucial part of eye healing after certain injuries or surgeries. Per the surgeon’s instruction, place two eye pads over the eye, then cover with a protective eye shell. Tape the shell to the face from the forehead above the nose and diagonally to the cheek. Be careful when removing the shell and pads for the post-op visit, as the area may still be tender.
Injection Prep Intraocular injections are often used to treat retinal problems. Typically injections are given to the eye through the sclera, which is somehow not as uncomfortable as it sounds. The patient is numbed prior to the procedure using local agents (tetracaine drops, maybe some subcutaneous lidocaine) but they are fully awake the whole time. No twilight. No general anesthesia. All procedures differ in set up and virtually every physician has their own way of doing things. Since no doctor or office has the same setup, you’ll probably have to memorize the very specific order for every doctor that you prep with. First things first: injections, as stated previously, are intraocular, meaning the needle goes through the front of the eye. Because of this, the procedure has to be sterile, otherwise, you risk your patient developing an infection like endophthalmitis. Endoph is one of the scariest things you’ll see in ophthalmology outside of a foreign body sticking out of the eye or a globe rupture. The infection can spread from one eye to the other, cause complete blindness and in worst-case scenarios require evisceration or enucleation. Scrub up, keep medications in a clean area and, if you’ve drawn the serum, keep it on a sterile field. If your doctor requires the use of a speculum, place a sterilized one on the field as well. Keep. It. Clean. Some doctors don’t want technicians doing anything but giving the prep drops. Physicians may use proparacaine to numb the eye, but tetracaine is a stronger anesthetic and is typically used instead. Betadine is
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instilled in the eye and, for certain doctors, along the lash line before treatment. If your office allows you to draw the medication, double and then triple-check that you have the correct medication. Some injectables cost over $7,000 per vial and your manager may write you up if you draw and waste that much money’s worth of medication over a careless error. Even worse, if the error is not caught in time, the doctor could inject the wrong medication into the patient’s eye. When preparing the injection, if you see that the doctor has switched from one medication to another, say Lucentis to Eylea after 10 treatments, verify this change before drawing the drug. The physician may truly want to switch it up, but in some cases, they or the scribe may have accidentally entered the wrong medicine into the chart. Just remember to be super careful at all times. Avastin comes pre-drawn so once you open the package it’s shipped in, you’re ready. Lucentis 3 and 5 need to be drawn, so slowly draw to avoid bubbles in the syringe. Eylea is extremely viscous and pulling too fast will leave your syringe looking like it’s filled with carbonated water. Take extra time when drawing Eylea. Occasionally, doctors and technicians hold the vial in their hand to slightly warm it up before drawing because this helps thin the medicine out a little, but these drugs are meant to stay at a particular temperature so they should not be left in room temperature for too long. Most doctors use a speculum to hold the eye open for the procedure. Make sure that the instrument stays sterile from the time you open the sterile pouch or pull it from the autoclave. If the instrument gets dirty before it is used, you increase the risk of infection from the procedure. Even if your office does not make the use of gloves mandatory, it is best practice to wear them. Gloves provide a protective barrier between you and the patient and they just look more professional. In the event that your doctor does not use a speculum, you may have to become a human speculum and manually hold the lids of your patient open for their injection. This might sound crazy, but some research found that the use of speculums caused increased discomfort and complications than injections performed without one [46]. If this is the case, glove up and
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firmly hold the top lid to the brow bone and bottom lid toward the cheekbone. No matter what, you cannot let go of either of those lids. When the injection is finished, your doctor may want you to use sterile saline to rinse out the treated eye. The betadine drops used to sterilize the site are no joke and can severely dry the eye out. After they are cleaned and ready to head out, make sure the patient has a clear understanding of what they should and shouldn’t do in the days after their treatment. Although every practice will have their own way of giving instructions, whether printed with their visit summary or on a photocopied paper that is easy for anyone in the office to find, the instructions are roughly the same everywhere you go. No water in the eye, no swimming and no contacts for a few days to a week. Remind your patient that they may see an increase in floaters as the medication settles but they should call or visit if they see the ominous curtain or veil, have flashes or develop vision loss.
Laser Prep Often, doctors will perform laser procedures in the office. For many problems in ophthalmology, there are a number of lasers that can be used to treat patients. If a person has anatomical narrow angles, they may need a Laser Peripheral Iridotomy (LPI) or if their intraocular pressures are too high, they might require Selective Laser Trabeculoplasty (SLT) or Argon Laser Trabeculoplasty (ALT). With retina, detachments can be sealed via laser, as can proliferative retinopathies, where lasers are used to seal off leaking vessels. After cataract surgery, several patients develop posterior capsule opacification (PCO) and doctors can use a YAG laser to clear it up. Most lasers take no more than 15 minutes and only require topical agents, like proparacaine and either a dilating or miotic drop, depending on the procedure. Just like in any routine eye exam, checking current medications, visual acuities, pressures, etc. are required for laser patients, even if they are only there for the laser without an actual exam. These are all important markers that physicians use to track any changes before and after the laser.
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Lasers and equipment vary office to office, but take the time to learn the machines that you have and what every function does; this will help you learn what to do if and when your doctor tells you to change the settings on the laser. When you are in the room with the physician and patient for the procedure, you’ll need to wear laser safety goggles. These goggles will protect your eyes from the laser and the light that emits. Exposure to the lights can cause damage to the eye and that’s the last thing you need as an ophthalmic assistant. The eye shields might not be the most fashionable, but they are mandatory. Once your doctor has you fire up the machine and the patient is getting their treatment, pay close attention to your surroundings. It is very easy to get bored or distracted when no one is talking and the only stimulus is the repetitive beeping sound of the laser when it is in use. Throughout the procedure, the physician may have you turn the intensity up or down, so it is best to stay beside the machine while staying out of the way. The doctor needs you to be quiet and still to eliminate distractions and incidences of equipment getting knocked into by accident. Following the laser, your patient will need to have their eye(s) rinsed of the lubricant from the physician’s lens. Have your patient tilt their head back and toward the side that you’ll be cleaning. Hold a tissue beside their eye and rinse with sterile saline, catching the runoff with the tissue. If using single-use vials of saline, which is far best for sterility, unload one or two per eye that you’re rinsing. Dab excess liquid for the patient and explain that their eye may feel irritated for the next few hours. Give them their post-op instructions and go over them verbally, asking if they have any questions. Remind them to call or come in with loss of vision, pain, flashes or floaters. In most cases, patients can shower normally as long as they avoid getting water in the eye and, just like with any other ocular procedure, they should avoid swimming and contact lens usage for a few days.
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APPENDIX C: SCRIBING If surgical assisting isn’t your thing, another way to learn and advance in eyecare is through scribing. Scribing is one of the funnest aspects of teching, but it can be hard work. Not everyone likes being a scribe, and that’s okay, but as an ophthalmic assistant, you learn more in the room with the doctor than as a surgical or vision tech. Most practices hold scribes as a position for seasoned personnel or lead technicians but some use postbaccalaureate students who are looking for medical experience before enrolling in med school (normally, only hospitals go this route, but not typically in ophthalmology). Being a scribe requires knowledge of both ophthalmology and the EMR that your office uses. Just as important, scribes need to be able to listen attentively and think intuitively your doctor is counting on you to fill in the chart accurately while billing properly and he or she will want you to do so without any hiccups. This means you have to be able to jump from one screen to next so the physician can review past findings as you input new ones. Practice makes perfect here and most of the rhythm of scribing comes in time. Eventually, you’ll have the exact order of the exam workflow memorized for every doctor that you work with. You’ll also need to think about when to fit in other parts of the note when the doctor is talking to the patient about things that do not necessarily need to be entered. One of these parts is billing; when time permits, you can begin to enter the CPT codes that you know your doctor will bill for. There are differing codes for the many parts of the exam, as well as the different types of exams (new, return, etc.) and since the rollout of ICD 10, you’ll need to specify right eye, left eye or bilateral for your diagnosis codes. Same day injections and lasers require modifiers and certain components cannot be billed in the same day, so be sure to bill for what you can, otherwise, you’ll either have to redo it until it goes through or your doctor won’t get paid for the visit. And yes, it may be the 21st century but all techs and scribes need to know their way around a paper chart. Only a few small private practices solely rely on paper charts anymore (which will eventually change when
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government regulations eventually force them to switch to electronic) but knowing how to correctly fill the sheets in is fantastic in case your EMR goes down, which it no doubt will at some point or another. Most of the chart is self-explanatory, but the billing sheet isn’t always pretty. Utilize your time properly, checking boxes and typing findings in as your doctor relays findings to you.
APPENDIX D: RESEARCH None of us would have our jobs in eyecare if it wasn’t for the extensive research by ophthalmologists and scientists who figured out how the eye works and what therapies are best to treat it. Everything from drops to low vision devices to surgical procedures has been studied repeatedly through trials before making their way into the office. Many doctors and practices work directly with researchers, but some may decide to participate in a clinical study and participating technicians will need to remember a few key things. 1. To be uniform, studies require special certifications based on the project. For these, you may be tested on research practices as a whole but you’ll most likely need to know specifics based on the study or what it is aiming to treat. Management or the researchers in charge of the study can provide particulars of these certs. 2. Professionals involved in research studies must know how to speak in terms that are easy for anyone to understand while knowing the advanced medical terminology for the project. Enrolling patients into a study requires patience and kindness, as you’ll have to read through documents when they are being consented. Also, the patient may have questions about what forms they are signing or details about the trial itself which you may have to answer. 3. Finally, the exam itself needs to be uniform. This means following the exam protocol thoroughly. Though you shouldn’t ever take
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shortcuts during the eye exam, skipping steps or differentiating at all can void your patient’s exam and potentially harm their participation. By being patient and following the rules, you can potentially help in the future of eyecare.
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ADDITIONAL RESOURCES Optometric and ophthalmic assistants have a world of knowledge at our fingertips. While this can seem overwhelming at times, we’re actually quite lucky. The only thing preventing us from learning more is ourselves. The first places for optometric techs to start looking for learning materials are through the American Optometric Association (AOA.org) and the Commission of Paraoptometric Certification (aoa.org/ paraoptometrics). Certifying through the CPC is a great start to advancing your career in optometry and looks great on a resume. In addition to the AOA, ophthalmic assistants can also look to the American Academy of Ophthalmology has countless articles for more indepth topics. The International Joint Commission of Allied Health Personnel in Ophthalmology (IJCAHPO.org) is the certifying body for ophthalmic techs. Alongside the COA, COT, and COMT certs, they offer Ophthalmic Scribe Certification (OSC), Ophthalmic Surgical Assistant (OSA), Registered Ophthalmic Ultrasound Biometrist (ROUB), Certified Diagnostic Ophthalmic Sonographer (CDOS), and Corporate Certified Ophthalmic Assistant (CCOA) certs. Ophthalmic photographers have the Ophthalmic Photographers’ Society (OPSWeb.org) for continuing education credits and info on the various forms of ocular imaging. This organization also offers credentialing with the Certified Retinal Angiographer (CRA) and the OCT
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Certification (OCT-C). Bryson-Taylor publishing publishes a line of books on OCTs and photography available through their website (brysontaylor.com/shop). Optics nerds have certifying options through the American Board of Opticianry and National Contact Lens Examiners (ABOC-NCLE.org). Opticians and lens fitters have three levels of credentialing: ABOC, ABOC-AC, and ABOM for eyeglasses and NCLE, NCLE-AC, and NCLEM for contact fitting. The Contact Lens Society of America (clsa.info/) is chock-full of webinars, credits and learning materials for those interested in fitting lenses as well. All of the above certifying bodies have study guides available in their online shops. On mobile devices, the Association of Technical Personnel in Ophthalmology (ATPO.org) has the ATPO COA Exam Flashcard app and Upward Mobility has apps for Ophthalmic Assistant Exam Prep and Ophthalmic Technician Exam Prep. Heidelberg Engineering (HeidelbergEngineering.com) has an OCT Examination app for studying the OCT-C test and Wills Eye (WillsEye.org) has its coveted Wills Eye Manual in app form now. Dr. Tim Root’s Ophthobook (timroot.com) is available in print or PDF form and is one of the best books you can read if you are getting into eyecare. The EyeCare Marketplace (store.jcahpo.org) is an excellent place to look for books, courses, and study guides. EyeCare CE (eyecarece.jcahpo.org/) is full of online classes that are eligible for credits for certified techs but are great to learn from even if you aren’t certified. Sharon Alamalhodaei, COMT, OSC has created books and prep courses for techs via the Eye Tech Training page (EyeTechTraining.com) and I can personally attest to her products (I took her Medical Technologist Prep Course before taking the COMT exam). Lastly, there are physicians and fellow techs out there who are willing to help you learn – the more informed a tech, the easier work is for everyone else. Ask the people in your office for help, tips, and tricks. Facebook has groups full of eye nerds who are also hungry for knowledge and eager to help. Whatever the case, take initiative and do what you can
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to learn as much as you can. No one has ever regretted learning too much about the field but there are certainly those who regret not learning enough.
ABOUT THE AUTHOR
Keli B. O’Connor, COMT, ABOC Clinical Coordinator, Center for Advanced Retinal & Ocular Therapeutics at University of Pennsylvania, Philadelphia, PA, USA Email: [email protected] Keli B. O’Connor, COMT, ABOC is the Clinical Coordinator for the Center of Advanced Retinal & Ocular Therapeutics at the University of Pennsylvania. A board-certified optician, she regularly teaches lensometry to residents and fellows, trains new technicians for the Institute and has instructed at the JCAHPO Annual Continuing Education Academy. The Optimal Tech is her first book.
INDEX A abrasion, 60 acuity, 20, 21, 22, 38, 45, 46, 47, 61, 87 afferent pupillary defect (APD), 19, 23, 24, 47, 74, 135 age-related macular degeneration (AMD/AMRD), 67, 68, 69 Alger brush, 59 angles, 27, 28, 50, 116, 127, 138, 147 anisocoria, 24 anterior chamber, 9, 11, 27, 28, 49, 50, 113, 116, 119, 120, 138 Argon Laser Trabeculoplasty (ALT), 147 artery occlusion, 74 A-scan, 118, 119, 157 astigmatism, 36, 39, 55, 56, 61, 104, 117, 125, 132 autorefractor, 33, 37, 41 axis, 36, 39, 56, 57, 58, 104, 108, 125, 126
B bifocal, 41, 126, 127, 131 blepharitis, 94
blepharospasm, 93 botox, 89, 93, 144 Brightness Acuity Test (BAT), 46 B-scan, 118, 119, 120
C calipers, 139 cancer, 72, 76, 84, 89, 97, 135 cataract, 18, 45, 46, 47, 55, 84, 85, 116, 117, 139, 142, 144, 147 cautery, 141 central serous, 69 chalazion, 89, 95, 97, 141 chief complaint (CC), 17, 18, 85 choroid, 11, 72 clean, 62, 133, 137, 142, 144, 145 color vision, 20, 83 cone, 11, 12, 55, 70 confrontation field, 19, 20, 84, 102 contact lens, 35, 37, 47, 56, 58, 60, 62, 132, 148 cornea, vii, 9, 10, 27, 30, 31, 32, 33, 36, 46, 50, 55, 56, 57, 59, 60, 61, 62, 63, 64, 65, 90, 91, 96, 97, 116, 117, 118, 119, 120, 133, 140, 142, 144
166
Index
corneal degeneration, 61, 63 corneal melt, 60 cortex, 11, 46, 109 cover/uncover, 26, 28, 29, 59, 80, 111, 145 cranial nerves, 81, 87 cylinder, 36, 37, 39, 41, 55, 104, 125, 126, 132
D dermatochalasis, 93 detachment, 74, 75, 76, 77 diabetic retinopathy, 68, 69, 78 diaton, 33 dilation, 3, 4, 5, 20, 29, 113, 119 disinfected, 142, 143 drops, 4, 5, 24, 28, 29, 30, 43, 47, 49, 50, 51, 59, 60, 63, 73, 91, 102, 113, 139, 144, 145, 147, 150 drusen, 83 dry eye, 14, 32, 61, 62, 64, 65, 91, 92, 94, 97, 116 duochrome, 40
F flashes, 18, 26, 65, 74, 75, 76, 77, 78, 85, 86, 97, 113, 147, 148 floaters, 18, 26, 65, 73, 74, 75, 76, 77, 78, 85, 86, 97, 147, 148 fluorescein angiography, 114 forceps, 59, 77, 140 foreign bodies, 14, 59, 90 fundus, 20, 27, 49, 71, 74, 77, 112, 113, 114, 115, 138
G ganglion cell, 12 glasses, ix, 19, 20, 21, 22, 35, 36, 42, 44, 47, 48, 56, 58, 61, 86, 104, 123, 124, 125, 127, 129, 130, 131, 132, 134 glaucoma, vii, 13, 17, 24, 29, 30, 34, 49, 50, 86, 102, 106, 107, 109, 116 globe rupture, 63, 145 Goldmann tonometer, 30, 64 Goldmann visual field, 102 guttata, 64, 65, 115, 154
E ectropion, 91, 156 emergent, 19 endophthalmitis, 145 endothelium, 9, 10, 116 entropion, 90, 91, 156 epiretinal membranes (ERMs), 77 episcleritis, 11 epithelium, 9, 10, 12, 61, 112 erosion, 60 exophthalmometer, 92, 156 extraocular muscles, 9, 13, 24, 26, 79, 82, 87, 139
H hemianopia, 19, 108, 109 hereditary retinal degeneration, 70 hippus, 24 history of present illness (HPI), 18, 69 hordeolum, 95 hyperopia, 36 hypertensive retinopathy, 69, 155 hypotony, 30
I iCare, 32 injection, 4, 78, 141, 144, 145, 146, 147
Index intraocular lens (IOL/IOLs), 46, 47, 48, 58, 117, 144 intraocular lens calculations (IOL Calcs), 117 intraocular pressure (IOP), 20, 27, 29, 30, 32, 49, 50, 60, 147 iris, 11, 23, 28, 50, 72, 76, 113, 116, 133
J Jackson Cross, 39
K keratoconus, 55, 56, 61, 65, 117, 132 keratometer, 56, 57 keratopathy, 62, 94 keratoplasty, 61, 64 Kimura spatula, 142 kinetic VF, 102
L lagophthalmos, 92, 93 laser, 30, 49, 50, 58, 61, 68, 69, 70, 71, 75, 76, 126, 127, 129, 147, 148 Laser Peripheral Iridotomy (LPI), 50, 147 lashes, 27, 90, 115 LASIK, 58 leadership, 5 lens, 10, 11, 35, 37, 38, 39, 42, 43, 45, 46, 47, 56, 58, 60, 86, 103, 104, 106, 115, 116, 117, 118, 119, 125, 126, 127, 129, 130, 131, 132, 133, 134, 144, 148 lenses (glasses), ix, 11, 14, 19, 20, 21, 22, 35, 36, 37, 38, 40, 41, 42, 44, 47, 48, 55, 56, 58, 61, 63, 65, 86, 103, 104, 123, 124, 125, 126, 127, 129, 130, 131, 132, 133, 134, 137 lensmeter, 123, 125, 130, 136
167 lid lag, 93 lids, 14, 27, 59, 76, 89, 90, 92, 94, 96, 97, 110, 114, 115, 116, 119, 139, 146 low vision, 41, 102, 150
M macula, 12, 22, 109, 114 macular sparing, 109 manifest, 5, 35, 36, 40, 43, 44, 104 marginal degeneration, 61, 154 meibomian gland, 14, 62, 95 myokymia, 93 myopia, 35, 58
N narrow-angle glaucoma, 116 needle holders, 140 needles, 140, 141 nerve fiber layer, 12 nystagmus, 23, 44
O oblique muscles, 14, 87 occluder, 26, 104 octopus, 86, 101, 103 oncology, 76 open-angle glaucoma, 30 ophthalmoscope, 137, 138 optic nerve, 9, 13, 24, 43, 49, 79, 81, 83, 84, 87, 94, 106, 109, 111, 113, 114, 118, 119 optic neuritis, 83 optical coherence tomography (OCT/OCTs), ix, 5, 12, 33, 84, 111, 112, 113, 116 orbit, 9, 15, 85, 90, 96
168
Index P
R
pantoscopic tilt, 131, 134 panuveitis, 73 papilledema, 83, 109 patching, 145 phenylephrine, 29 phoria, 27 phoropter, 36, 37, 38, 39, 41, 42, 43, 132 photography, 3, 67, 71, 89, 113, 114, 115, 118, 119 photoreceptor, 12 pinhole, 22, 23 posterior capsule opacification (PCO), 147 posterior subcapsular, 45 posterior vitreous detachment (PVD), 77 Potential Acuity Meter (PAM), 46 presbyopia, 41 prescription, 19, 20, 35, 36, 37, 38, 40, 41, 42, 44, 47, 103, 104, 123, 124, 126, 129, 132, 133 pressure, 13, 18, 20, 30, 32, 47, 49, 69, 85, 86 prism, 31, 32, 35, 87, 123, 124, 125, 127, 129, 130, 131, 134 PRK, 58, 142 proptosis, 89, 92, 93, 94 pseudopapilledema, 83 pseudophakia, 47 pseudotumor cerebri, 83 ptosis, 73, 81, 82, 89, 91, 92, 102 pupils, 19, 20, 23, 24, 34, 47 Pupils, Equal, Round, Reactive to Light and Accommodation (PERRLA), 19 Putterman clamp, 142
radial keratotomy(ies) (RKs), 58 recti muscle, 13, 80 refinement, 38 refraction, vii, 35, 39, 40, 41, 43, 44, 46, 47, 104, 124, 153 refractive surgery, 58, 61 reticle, 130 retina, vii, xv, 9, 10, 11, 12, 17, 24, 37, 46, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 83, 109, 111, 112, 113, 118, 119, 120, 139, 147 retinopathy, 67, 68, 69, 70, 71, 72, 73, 155 retinoscope, 37, 137, 138 retinoscopy, 36, 37, 38, 41, 138 rigid gas permeable lenses (RGPs), 56, 61, 65, 132 rod, 11, 13, 70 routine, 17, 18, 19, 33, 76, 95, 128, 147
Q quadrantanopia, 108, 109
S scissors, 140 sclera, 9, 10, 27, 72, 76, 96, 118, 119, 120, 145 scleral buckle, 75 scleritis, 11 scotoma, 107 scribing, 18, 149 Selective Laser Trabeculoplasty (SLT), 147 slit lamp, 20, 27, 28, 30, 31, 32, 34, 46, 60, 64, 97, 115, 117, 133 soft skills, 5 spectralis, 109 specular endothelial micrography, 116 speculum, 139, 145, 146, 157 sphere, 35, 38, 39, 41, 42, 55, 104, 125, 126, 132 static VF, 102
Index stereo photos, 114 stereopsis, 20 sterile, 59, 137, 142, 143, 144, 145, 146, 147, 148 strabismus, 79, 87, 139 stroke, 21, 84, 102, 109 stroma, 9, 10 stye, 95, 156 superficial punctate keratitis (SPK), 64 surgical assisting, 137, 143, 149 swing light test, 23, 24, 138 syringes, 141
T tear film, 61, 154 thyroid eye disease, 87, 92, 94 tonometer, 5, 28, 32, 33, 47, 50, 60 tonopen, 32 topography, 56, 117 toric, 132 transilluminator, 23, 25, 137, 138 trauma, 24, 29, 30, 34, 45, 50, 62, 73, 75, 91, 92 trial frame, 38, 41, 42 trichiasis, 90 tropicamide, 29 twitching, 89, 93
169 U ulcers, 62, 63, 117 ultrasound, 118, 120 urgent, 19 uveitis, 72, 73
V Van Herick technique, 28 vein occlusion, 73, 74 vergence, 26 version, 25 visual field, vii, 13, 19, 49, 74, 79, 84, 86, 89, 93, 101, 102, 103, 105, 106, 107, 108, 109, 135 vitreous, 9, 10, 11, 12, 75, 77, 78, 118, 119
W Weiss ring, 77 Worth four dot, 86
X xeomin, 93
Y YAG laser, 147