The goal of the lecture is to provide an overview of amblyopia and the risk factors associated with this diagnosis. The lecture will also go over the major studies that have shaped the treatment of amblyopia.
Lecturer: Dr. Jenelle L. Mallios, OD, FAAO, Dipl of ABO, Associate Dean of Clinical Affairs, Associate Professor, Midwestern University | Chicago College of Optometry, USA
DR MALLIOS: Hi, everyone. Just give me one moment, while I set up the screen. My name is Dr. Jenelle Mallios. I am the Associate Dean of Clinical Affairs at the Chicago College of Optometry. I graduated from the New England College of Optometry in 2010, and then I did a residency, again, through the New England College of Optometry, from 2010 to 2011. From there I worked at a hospital in the pediatric ophthalmology department at Tufts University in Boston for a few years, and from there I moved to New York, and I became the chief of pediatrics at the SUNY College of Optometry, I worked at SUNY for four years, and about a year ago I moved again, and now I’m in Chicago, and I work for the newest optometry school in America, which is the Chicago College of Optometry, and like I said, I’m the Associate Dean for Clinical Affairs. And I’m really excited to teach you guys, refresh your memories, on the diagnosis and management of amblyopia. And I’m gonna apologize in advance. Because I won’t be able to look at the camera the entire time. I have another important that I’m looking at. So if I look to the side, that’s why. So let’s just go over the outline. We’re gonna go over the definition of amblyopia, the amblyogenic factors, which is obviously really important, amblyopia findings, and we’re gonna talk about a lot of the ATS studies, because the way that we have learned to practice really does come from a lot of the PEDIG studies. The pediatric eye disease investigator group did a lot of studies, and a lot of how we practice comes from there. There’s a few more studies. We’ll talk about microtropia, compliance, and what an exam for amblyopia looks like. The learning objectives are to apply knowledge from the amblyopia studies to an amblyopia therapy regimen. And then understanding the concepts from amblyopia studies, and then integrating them with prescribing. So in regards to the definition, it is a unilateral or bilateral decrease in vision, caused by visual deprivation with no ocular pathology. And obviously that’s bolded for a reason. That’s really important, that we can rule out any ocular pathology. And with that being said, you can only rule out ocular pathology if you’ve dilated the eye, and made sure that in the retina we’re not seeing any other ocular disease happening. We would have to diagnose this during childhood. And then there has to be an amblyogenic factor. An amblyogenic factor can be anything from form deprivation, strabismus, anisometropia, or high isometropia. Those last two are definitely considered more refractive error-related, and we’ll talk about them — but when you’re thinking about what would be amblyopia, the developing visual system is very sensitive to the visual experience. And interruption by any obstacle — so that could be blurred vision or strabismus — before the age of 7 or 8 years old, that’s why I’m saying it has to be diagnosed in childhood — results in reduction of visual capacity. And that’s what’s considered amblyopia. Or that’s what we know as amblyopia. The eyes are fully developed at birth, but those connections are not fully formed from the eye to the brain. So if something interferes with that, the connections never form or they abnormally form. So again, just talking about the amblyogenic factors, in this slide, we’re only gonna talk about the form deprivation and strabismus, and then we’ll talk about refractive amblyopia as well. So for strabismus, it’s a misalignment of the eyes, which results in suppression of input from one eye in order to avoid visual confusion. The criteria for that, in order for it to cause amblyopia, would be that the strabismus has to be constant or mostly constant, so, like, 90 to 95% of the time it’s turning. Unilateral or mostly unilateral. It has to be at both distance and near. The direction — it’s obvious it’s going to be eso or exo, and sometimes even hypers can cause an amblyopia secondary strabismus as well, and again, onset before the critical period. So with that being said, if someone had trauma to their eyes at the age of 12 and then they have a strabismus secondary to trauma, we can’t call that amblyopia, because they’ve gone through their critical period, being able to make all those connections from their eye to the brain, because their eyes have been aligned, and then the trauma or the strabismus happened after that critical period, so we wouldn’t say that there’s amblyopia secondary to strabismus. However, again, it’s really important that the strabismus is constant, unilateral, and both at distance and near. For form deprivation, different examples of what would be causing amblyopia would be something like a congenital cataract, maybe an early complete ptosis, or at least a ptosis that’s past the visual axis. A corneal opacity or a vitreal hemorrhage. So based off of this, we’re gonna go into our first poll question, which is: Which of the following examples will potentially have amblyopia secondary to strabismus? Great. So the options were a 12 pd intermittent left exotropia at distance and near. This wouldn’t be correct, because it has to follow the guideline we just discussed. It has to be constant, unilateral, and both distance and near. It was unilateral and it was both distance and near. However, it was intermittent and not constant. Number two was a 20 prism diopter constant alternating esotropia at distance and near. Again, we have the constant part and we have the distance and near part, but we’re missing the unilateral portion. If it’s an alternating esotropia, you’re still getting feedback in each eye, so it wouldn’t cause amblyopia. So the 20 prism diopter intermittent alternating exotropia at distance and a 10 prism diopter exophoria at near — that doesn’t have any of the qualifications. So it does have to be constant and unilateral, where there was intermittent and alternating, and then it has to be at distance and near, and we saw the trope was only in the distance in that example. And it was a phoria at near. So it wouldn’t cause amblyopia. So the last option, D, was actually the correct one. And so the amblyogenic factors for refractive amblyopia — so we have isometropia and anisometropia. So for isometropia, that means both eyes have to have a minimum of this number or higher. In the sphere. And I guess one thing that I should tell you that I should have corrected the slide — they’re all greater than or equal to. So for astigmatism, for isometropia, it would be greater than or equal to 2.5 diopters. So both eyes have to have at least 2.5 diopters of astigmatism or more. For hyperopia, both eyes have to have at least 5 diopters of hyperopia or more in both eyes, and then for myopia, it would have to be 8 diopters of myopia in both eyes or more. For anisometropia, the astigmatism — so this is the difference. They don’t have to have a minimum of 1.5 diopter of astigmatism. The difference between the two eyes has to be 1.5 diopters between the astigmatism. So let’s say one eye was completely plano, and the left eye was plano -1.50, axis 1.80. That would qualify them for having amblyopia, because there’s a difference of 1.5 diopters between the two eyes. For hyperopia, it’s a difference of 1 diopter between the two eyes, which is really not a lot if you think about it in general. And for myopia, it’s 3 diopters’ difference between the two eyes. And I should explain that when we talk about these values, this is not from dry refraction. This would be from the cycloplegic refraction. The reaction we would get from that is what is causing amblyopia. That’s because kids might be accommodating, so you’re not seeing their full latent prescription if they are hyperopic. You wouldn’t see the anisometropic distance. A lot of times we can pull that out when we’re cyclopleging. So it’s important that the refraction we get from that is what we’re basing our findings off of. So based off of this slide, we’re going into our poll question number two. So this is a cycloplegic refractive error. It doesn’t say that in the question, but given the following refractive error, what type of amblyopia does this patient potentially have? So in the right eye, we have +5.25, -2.75, axis 180. And in the left eye, we have +4, -2.50, axis 180. So the question is asking: Which one of these answers shows all the types of amblyopia that might exist in this example? Okay. So… Let’s break this down a little bit. So we just discussed the amblyogenic refractive errors between isometropia and anisometropia. So let’s look at the spherical part first. In order for there to be isometropic hyperopia, it would have to be +5 diopters of hyperopia in both eyes. So we see in the left eye there’s only +4. So we know that the amblyopia in both eyes wouldn’t be from the hyperopia being high in both eyes. However, when we’re looking at the sphere, we do see that there’s an anisometropic difference of at least 1 diopter. There’s a 1.25 diopter difference between the two eyes. So the first one would be partially correct. There’s amblyopia OD secondary to anisometropic hyperopia. However, now we have to look at the astigmatism. So we said that for astigmatism, you need to have at least 2.50 — if you have at least 2.5 diopters of astigmatism in both eyes or more, then that would be cause for isometropic astigmatism, so amblyopia secondary to isometropic astigmatism. So this patient would have both types of amblyopia. So the second one, again, like I said, is technically correct, but it doesn’t encompass both aspects of it. And the third one is actually the correct answer, because there’s amblyopia in the right eye, more than the left eye, because of the anisometropic hyperopia, and because they also have high astigmatism OU. If they didn’t have high astigmatism OU, then it would just be amblyopia OD secondary to the anisometropic hyperopia. The last one, as I mentioned before, is incorrect because, while we do have the anisometropic hyperopia, the high hyperopia is not OU. If the left eye had been +5, -2.50, axis 180, then the last statement would have been true. Amblyopia is also a spatial vision problem. A lot of times when you consider amblyopia, we just think of it as reduced vision. But if we think about just the central or parvo cells, at high spatial frequency, high contrast, low temporal frequency, and photopic light conditions, whereas when we think about peripheral magno cells, that’s for low spatial frequency, low and middle contrast, high temporal frequency, and mesopic light conditions. Amblyopes tend to use their magno cells more than they’re using their parvo. And it is more than simply reduced visual acuity. While we have decreased best corrected visual acuity in both eyes, we also have decreased stereopsis, which is why we check stereopsis. They would also be affected by the crowding phenomenon. So if they’re doing — if we’re checking visual acuity, it’s so important in pediatric patients that we have a full line of crowding, when we’re checking visual acuities, because they will be sensitive, and it will help us pick up the amblyopes. Whereas often when we examine a pediatric patient, it’s really tempting to do an isolated optotype so the child can read it easier. But what often happens is we overinflate the visual acuity and don’t pick up the fact that they really are an amblyope. I work at a school and work with students, and I always tell my students: I don’t necessarily want it to be easier for them, just by doing it isolated. I want to truly know if we’re picking up the amblyopia or not. If you have a computerized visual acuity chart, if you do want to make it slightly easier for the child to help their attention, you can use the arrow function underneath, or if you’re gonna make it isolated, a lot of the computerized visual acuity charts have the crowding bar option, so you’re isolating, but they have the crowding bars, so the crowding phenomenon still exists in those cases. There might be strabismus, which we talked about earlier. And additional findings that wouldn’t be uncommon to see would be poor eye tracking, reduced contrast sensitivity, abnormal spatial distortions, normal peripheral vision, and then of course like I said before no clinically apparent ocular or visual pathway anomalies. Key points for the diagnosis of amblyopia. Amblyopia is a diagnosis of inclusion and exclusion. Diagnosis must make sense in severity. And the response to treatment is part of the diagnosis. So we’re gonna talk about each of those points in the next few slides. I see that there are some questions, but I’m gonna wait for the questions until the end. I’m not ignoring you, I promise. So for the exclusion portion, for the diagnosis, we have to rule out ocular pathology as a cause of decreased vision by at least performing a thorough anterior and posterior ocular health assessment, with dilation. For the inclusion component, we must be able to document a specific etiology for the amblyopia, such as an amblyogenic refractive error, amblyogenic strabismus, like I talked about, constant, unilateral, both distance and near, and amblyogenic form deprivation. And it’s important when you’re charting a patient who has potential amblyopia, you’re going to label the type of amblyopia. Is it strabismic amblyopia? Is it strabismic and refractive amblyopia? If it is, what are the amblyogenic refractive errors that we discussed, like in the example prior? The severity has to make sense. The expected visual acuity loss is secondary to the amblyopia. For anisometropic and strabismic amblyopes, typical acuity loss is 20/30. So maybe I would expect my eye that’s +1 to be around 20/40. I wouldn’t expect decreased vision in the +1 eye if there’s only one diopter difference between the two eyes to be 20/50. However, on the flip side, if I was plano in one eye, and +8 in the other eye, there’s a huge difference, a 8 diopter difference, between the two eyes, so I would expect that the vision loss in that amblyopic eye would be worse than in someone who had just a 1 diopter difference. What I do notice is that when I do have a myopic anisometrope patient, there typically is a more dense amblyopia in those patients. If I have a patient who is plano and -10, that -10 eye is typically — it can be up to 20/400. That’s one of the exceptions to the rule, and I would have to imagine that that visual acuity loss, while it is amblyopia, I think just having a -10 eye also just — there’s stretching of the retina, the eye is longer, there’s other physical attributes to the vision loss. But in general, we would never have a no light perception from amblyopia. We would never have a patient whose light perception from amblyopia — there is typically acuity that you would see. A longstanding strabismic amblyope — if you’re not seeing them until 8 years old, I would expect their vision to be reduced more than a patient who was caught at 3 years old. Form deprivation can be worse. If it’s secondary to cataracts, if they’re not treated in the first six weeks, their amblyopia may be reduced. And then if you think about a patient who… I know I talked about it in regards to strabismus, but really in anything, if I have a three-year-old where I found their refractive amblyopia, versus an 8-year-old for their first eye exam, I would expect that my end result or prognosis for the 3-year-old would be better than my prognosis for the 8-year-old with the same refractive error. Because the earlier you treat them, the better you expect them to be. And response to treatment is important. Their vision should get better as treatment begins. And that’s just understanding the prognosis. Which we’re going to talk about through all of the amblyopia treatment studies. And if there’s no improvement, we have to ask ourselves: Is there an incorrect diagnosis? Is there potentially the wrong prescription? And are they compliant? Are they compliant with wearing their glasses? Are they compliant with the treatment options, whether that’s patching or atropine, whatever we’re choosing to do for their treatment. So the less factors that you would have… So let’s say they’re only a refractive amblyope and not a refractive and strabismic amblyope, and you caught them early on — their response to treatment will be variable according to those factors. It’s very important that we’re giving them proper refractive correction. So we want to eliminate the optical blur and provide an optimal environment for amblyopia therapy, because that’s really essential to our therapy. This is based off the PEDIG protocols. PEDIG is a large network of pediatric ophthalmologists, optometrists, and orthoptists that have had a lot of studies over the years on different areas in pediatrics, but a lot in amblyopia treatment as well. So I just took this prescribing off of the PEDIG protocol. For anisometropia, the anisometropic difference between the two eyes must be maintained in the glasses. If I have a patient I’m prescribing glasses for and they have anisometropia, I have to maintain that difference. Let’s say I have a patient who is +3 and +5 with glasses. I can’t cut from one eye. I have to cut equally between the two eyes. So there’s a 2 diopter difference between the 2 eyes. If I want to cut 1 diopter in the +3 eye, I have to cut 1 from the +5. So the difference is still a 2 diopter difference. It’s very important when you’re prescribing that you keep that difference between the two eyes. For astigmatism, the full amount needs to be corrected. For hyperopia, if and when you’re reducing their hyperopia, without strabismus, again, it has to be done symmetrically. This is taking out the anisometropic portion. Let’s say you have a patient who is +5 in both eyes, and they have minimal phoria, no strabismus, and you want to cut some of the plus, and you decide to cut +1, you have to do so equally between the two eyes. However, we’ve learned that if you have a strabismus, specifically an esotropia, because an exo would be a very different picture — if you have hyperopia with an esotropia, you would want to prescribe the full amount of the plus. Or if you want to undercorrect, you can undercorrect by half a diopter, and this is again — you’re prescribing based off of the cycloplegic refraction. So I have cyclo’d my patient, they’re +5 in both eyes, and they have a 20 prism diopter esotropia. Then you want to prescribe the full plus or the +5 in both eyes, so you can hope that their eyes start to align, based off of their hyperopic prescription, or at the most, cut half a diopter, because of tonic accommodation. So you can cut that half diopter. Otherwise the least you can give them is a +4.50 in that example. For myopia, we prescribe the full amount. So I’m going to talk about all of the ATS or the PEDIG studies, but I’m gonna talk about them through a case. So we have a five-year-old female. The chief complaint is that they failed their school screening and the mom reports occasional squinting. Birth, developmental, and educational history all unremarkable. So the eyes are 20/60 and 20/100. That’s with Lea symbols, the full line. They show slight esophoria at distance and near, slit lamp was unremarkable. Their dilation is also unremarkable. I didn’t state it in the last slide. So my cycloplegic refraction shows +3, -3.25, axis 180 in the right eye, vision improved to 20/40, and in the left eye, +4.50, -3.50, axis 180, and vision was 20/80. I gave the full amount of astigmatism and axis. Kids adapt really well to prescribing. You don’t have to cut a lot from the astigmatism just because it seems like a lot for the prescription. I always give the full astigmatism. The only reason would be if they’re really young and I think they’re still emmetropizing. Then I might give them less, but that’s another lecture. For all intents and purposes, I’m gonna talk about basing it off the rules we just discussed. In the cycloplegic ret, there’s a 1.5 diopter difference between the two eyes. So I cut 1.5 diopters from each eye. You can see in the final prescription we still have a 1.5 diopter difference between OD and OS. So final RX is +1.50, -3.25, axis 180, and OS is+3, -3.50, axis 180. So it’s amblyopia OS greater than OD2 to high astigmatism and anisometropic hyperopia. So I educated the patient and asked them to return in three months for follow-up. The first treatment study we’re gonna talk about is ATS5, evaluation of optical correction alone in anisometropic amblyopes. In this study, they looked at patients between 3 and 7, between 20/40 to 20/250 visual acuity. Our patient fell in this range. And they showed that vision improved with glasses align in three quarters of the patients. The amblyopia resolved completely in 27% with glasses alone. In a quarter of the patients, even if they’re anisometropic, you don’t have to start patching right away, because based on the study we see we may never have to patch a quarter of the patients. I don’t know how many of you are patching your amblyopes regularly, but I’m sure the families have told you that patching is really difficult for kids and families to adhere to, from a compliance standpoint, because a lot of kids hate the patch. So if you don’t have to patch, that’s awesome. You’re making a patient very happy. Like I said, in this case alone, you just want to make sure that maybe the glasses can help. The average improvement was three lines. And the asterisk was saying that they defined as resolved was interocular difference of one line or less. Even though I have an anisometropic patient and think I need to patch, I’m not going to patch yet. I’m going to give them the glasses and monitor them every few months until they stop improving. ATS7 was a study that looked at optical correction for bilateral refractive amblyopia. Which was also our patient, because they did have the astigmatism in both eyes, but this one was purely bilateral refractive amblyopes. And in this study, they looked at 113 kids, 3 to 10 years of age, with 20/40 to 20/400 vision. And they found that glasses alone improved visual acuity to 20/25 or better within a year. There was no patching for these patients. So if you purely have a bilateral refractive amblyope, just giving them glasses alone should help improve. And remember in one of the first slides I talked about I was saying that the treatment of the amblyopia is really important. So if you’re seeing that you have a bilateral amblyope and they’re not improving, that’s when I would make sure that your prescription is correct. Are they wearing their glasses? Are they compliant with full-time wear of glasses? Sometimes I’ve had parents tell me: They’re wearing their glasses all the time and it might be true, but I look at the kid and the glasses are down here on their nose and they’re always looking above their glasses. You physically have the glasses on your face, but if you’re not looking through the glasses, then it’s not going to improve the vision at all. So that’s just looking at the patient and making sure that the glasses fit correctly. ATS13 was looking at optical correction for strabismic amblyopia or combined mechanism amblyopia. That means they have strabismus and a refractive error amblyopia as well. They saw that 75% of patients improved by at least two lines and half the patients improved by at least three lines, again, with glasses alone. So we’re not talking about the patching yet. There’s resolution of amblyopia, even though they were all at least strabismic. With glasses alone, it improved in one third of the patients, and there was greater improvement in strabismic amblyopia alone, but just by a line of acuity. So let’s talk about our patient again. So our patient returned after three months of me giving them their glasses, and their stereopsis improved and vision improved to 20/30 and 20/60. So what I said is: We’re just gonna keep wearing the glasses. We’re not gonna start patching or anything like that. Because I know at least a quarter of these patients will improve completely by glasses alone. So they come back for their third visit, and vision was 20/25 and 20/50, I had them come back again, and at visit four, they’re still 20/25 and 20/50, so the vision had plateaued, and so had stereopsis. I’m sure a lot of you heard about the study that talked about six hours a day of patching versus full-time patching. This study was looking at 175 kids with severe amblyopia. So a lot of people know this study, but I think they don’t realize that between this study and the next one I’m gonna talk about they looked at different types of amblyopes. So in this one, they were looking at patients who were severe amblyopes, and that definition of severe amblyopia is 20/100 to 20/400 vision, and they were either doing 6 hours or full-time patching. All hours or all but one hour. And they also did one hour of near work. Amblyopia secondary to strabismus, anisometropia, or both. And they found that after four months, the visual acuity actually improved similarly in both groups. So it was about four and a half lines in either group. We’re totally not gonna want to patch for a whole day if we don’t have to, if we will achieve the same results by just patching for six hours a day. But again, this is in a severe amblyope, whereas now we’re gonna talk about the ATS2B, which is the 2 hours a day of patching versus the 6 hours a day of patching. In this study, we saw it was 190 children, but they had moderate amblyopia. 20/40 to 20/80 visual acuity. And they patched either for 2 or 6 hours a day, with one hour of near work included during patching. It was amblyopia secondary to strabismus, anisometropia, or both, and they concluded that after 4 months, improve was similar between the two groups. Regardless of if they were patching for 2 or 6 hours a day, they improved the same. If we’re not gonna patch for 6 hours a day, I can just patch for 2 hours a day. But it’s important to know that a lot of people know these two studies, and what a lot of people interpret that as is that all patients need to only be patched for 2 hours a day. But it’s really that if you’re a severe amblyope, you would need to be patched for about 6 hours a day, as opposed to a whole day, and if you’re a moderate amblyope, you don’t need to be patched for 6 hours a day. You only need to be patched for 2 hours a day. And then we have our atropine study. It’s atropine versus patching for moderate amblyopia. They were either in 6 hours a day of patching… This is ATS1. Remember, the study I just talked about was ATS2, when we realized that we only have to patch for 6 hours a day. This study actually came before the other one. So either 6 hours a day of patching or one drop of atropine daily. The 6 month outcome was that improvement in VA was of similar magnitude from both therapies. Although improvements from patching were more rapid. Although it was more rapid, the atropine group caught up. At the end, the visual acuity improvement was the same in both groups. And what’s important that came out of this study as well is that the adverse effects in patching — 41% of the patients reported mild skin irritation at least once, whereas in the atropine groups, there was actually less adverse effects. But the most common one, which was reported for 18% of the kids, was that there was light sensitivity, as you would expect. Because they were using 1% atropine, so the pupils were pretty dilated. And in the quality of life questionnaire, scores were consistently worse for patching than atropine, with respect to adverse effects, difficulty with compliance, and social stigma. With that being said, I still do patch more often than I use atropine. I always start with patching and I will choose to do atropine if I’m not getting the results I want. And even for atropine, you have to make sure that it’s the right candidate to use atropine, and I’ll talk about that in a little bit. But then there’s another study… So can we just use atropine on the weekends, or do we have to use one drop of atropine every single day? So the group was split between either daily atropine or just weekend atropine for four months. And the results were that there was actually, again, a similar improvement in visual acuity, in both treatment groups. It’s really nice that if you are gonna use the atropine for moderate amblyopes — this is not for severe amblyopes — you only have to do it on the weekends. Which can be helpful for parents, to not have to instil a drop every single day in their child’s eyes. So then we have ATS6. And I included this study, because we always hear studies saying there was one hour of near work. When we patch, we have to make sure we do near work. They did a study looking at 2 hours of near work versus distance activities. They had 400 children in the study, all types of amblyopes, severe and moderate, and the amblyopia like all the other ones was due to aniso, strabismus, or both. And they were either doing 2 hours a day with near activities 2 hours a day of patching with distance activities. And at 8 weeks, there was a similar improvement in visual acuity in the amblyopic eye in both groups. So we don’t have to tell parents that the kids have to do near work the entire time. I know at least in the United States telling a kid that they have to play on their video games isn’t, like, the worst punishment for them. So if you have to tell them… You know what? You have to patch, and while you’re patching, you can do a near video game… Kids get really happy that the doctor is telling them to do that. But for some kids, maybe they don’t want to do video games. They can watch a movie. If you look up ATS6 in the study, they talk about the activities that were prescribed as distance and the ones that were prescribed as distance activities. It’s worth looking up if you have a moment. Now we’re on to poll question number three. A patient came in for their first eye exam and has been diagnosed with anisometropic refractive amblyopia, OD. 20/60. You prescribe glasses and the patient returns for their 3 month follow-up, and the vision improves to 20/40. What would your next step be? Great. So based off all of the ATS studies that we discussed, the option would be, because their vision has improved by two lines in those three months, we don’t want to start patching yet. We want them to stay in their glasses until you see their vision plateau, and once their vision has plateaued, then we might start patching or atropine. So what do we do now? Isn’t this picture so cute? Now what are we gonna do? So with our patient, the vision in the right eye was 20/25. And in the left eye was 20/50. And the stereo is 60 seconds. I actually prescribed three hours a day of patching, seven days a week, continued full-time wear of glasses, and return in three months. When they returned in three months, their vision improved 20/25 and 20/30 in the left eye. I said continue patching three hours a day, seven days a week, while continuing full-time wear of glasses. You just told us only patch two hours a day. Why are you patching three hours a day? Good question. There’s a study called MOTAS study, which objectively monitored how often people were patching. And the people in the study were either doing 6 or 12 hours a day of patching. There were 80 children in the study, randomized to either 6 hours a day of patching or 12 hours a day of patching, and they had an occlusion dose monitor. An electrode set up to a patch, that they were able to monitor how many hours a day the child was wearing that patch. And as you would guess, patients patch less than you tell them to. So in the 6 hours a day group, they averaged about 4 hours a day of patching, and in the 12 hours a day group, they averaged 6 hours a day of patching. So to me, if I tell a patient to patch 2 hours, they might patch 1 hour. And I should give the patient the benefit of the doubt, but I try to give them a range. So I’ll say… Patch for at least… The minimum is 2 hours. But I want your goal to be 3 hours. That way, even if they fall short, then maybe their minimum is 2 hours. So visit 6, the patient improved 20/20 to 20/25+. So this is excellent. So at this point, I prescribed two hours a day of patching in the right eye five days a week, while continuing full-time wear of glasses. So you’ll see it’s not seven days a week, and it’s not three hours a day anymore. Why is that? I’m gonna talk about two studies that are really important that go on that point. One is: Do we increase patching for amblyopia? They’re seeing that in a patient who has residual amblyopic vision after 12 weeks of patching 2 hours a day, they randomized those kids to continue 2 hours a day, or do we up their patching to 6 hours a day? These are stubborn amblyopes who improve, improve, improve, and just stop improving. What do you do with those kids? The mean visual acuity improvement at 10 weeks was 1.2 lines in the group that increased patching from 2 to 6 hours. If you need that last push, you’re almost there, increased the patching, they might not be happy with this, but they should increase their patching to 6 hours a day, because we do see continued improvement, whereas there’s only half a line improvement in the group that continues with 2 hours of patching. Among the increased patching dosage group, 40% showed at least two lines of visual acuity improvement compared to 18% in the group that continued with two hours a day of patching. Why did I taper before? Amblyopia recurrence once treatment is discontinued. So there was a study — once patients had been successfully treated for amblyopia, including patients both on atropine and also doing patching. Both were included in the study. And they follow them for one year to assess recurrence of amblyopia. And they actually found that recurrence occurred in one quarter of the patients who had been seen. So 25% of these patients had actually had recurrence of amblyopia. And their recurrence happened regardless of the treatment. So whether they were patched or with atropine, recurrence occurred similarly. So the data suggests recurrence in patients when patching stopped abruptly, rather than tapered. To me, I translate that as… And you saw that in my example… Maybe instead of… You have been doing three hours a day of patching, 7 days a week, we decrease the amount of days and decrease the amount of hours. So now we have our last poll question. Your amblyopic patient has completed patching therapy. They’ve been patching 3 hours a day, 7 days a week, and the vision is 20/20 in both eyes. What is your next step? Great. So we don’t want to discontinue the patching abruptly. Like I said in the last study, there is a higher chance for recurrence. So in that patient maybe I would start patching two hours a day, four days a week and follow up. If at the follow-up they’re still 20/20, I would discontinue the patching and continue to follow up for a year to make sure there is no recurrence. I want to talk about another study I thought was really important. It’s the treatment of amblyopia in older kids. What do we do with an amblyope who’s older? They looked at 507 kids with vision ranging from 20/40 to 20/400, and split them into two ages, the 7 to 12-year-old group and the 13 to 17-year-old group. They were either in a glasses only group or a 2 to 6 hours a day of patching group with near activity. What is also interesting is that in the younger group, the 7 to 12-year-old group, they also had them do atropine. So in the 7 to 12-year-olds, they were either in glasses alone or glasses and patching or atropine, and in the 13 to 17-year-old group, they were either in glasses or in patching. So there was no atropine involved with the older group. So what they defined as a responder in this group was if they improved in the amblyopic eye by at least two lines. What’s interesting is that amblyopia improves with correction alone in 25% of the entire group. So don’t not treat the older amblyopes. That’s what this says to me. In the 7 to 12-year-old group, treatment improved even if they had previous treatment. 53% of the treatment group were responders. Remember, they were with patching and with atropine. And in the younger cohort, at least a quarter of these kids were also responders. Again, that means two lines of visual acuity improvement or more. In the 13 to 17-year-old group, treatment improved if there had been no previous amblyopia treatment. Responder rates were similar in both groups, 25% to 23%, the glasses or the patching group. However, if there had been no previous amblyopia therapy, 50% of the treatment group were responders, 20% of the optical group. What does that mean, previous treatment, amblyopia treatment? I have so many kids, I’m seeing them as patients, and the parents are like… They patched when they were little. You dig a little deeper, and they patched for half an hour a day, five times in a month, and stopped. I would not consider that amblyopia treatment. They tried, but I would say they’re still considered a no treatment group, and I would even try to do the patching. So definitely dig a little deeper if someone tells you that they patched in the past, because that doesn’t always mean they were actually very compliant. I put this slide on there because I do think when you’re talking about amblyopia you should talk about microtropes. A microtrope is defined as a unilateral small strabismus of 8 diopters or less. And they have harmonious anomalous correspondence. They’re typically eso. And these patients, the picture that I’ve noticed — this happens when a patient has been patching and they’ve been on amblyopia therapy, and they’ve stopped improving, they’ve been very compliant, and their vision is 20/50, 20/40, stereo is 50 seconds, and they won’t get better. That’s when I test to see if they have a microtropia or monofixation syndrome. Different tests you can do to see if they have a microtropia is you can do visuoscopy, on the direct ophthalmoscope, where you have the different targets. One of the images is literally a target sign. I should have had a picture. I’m very sorry. So what I’ll do is I’ll show the child on their hand that target. You have them close — I would always do the good eye first. So have them cover their amblyopic eye, look into their good eye, and have them look in the middle of the target. You should be seeing their fovea. And I’ll do it on the amblyopic eye. If they have a microtropia, you’ll see unstable and unsteady movement of the fovea. It isn’t looking in the middle of the target. They’re very unsteady. I sometimes take a loose prism that’s a 4 base out. A normal response would be that if you introduce the prism on a normal seeing eye, remember your image goes towards the apex. So your eye will shift to the four base out. So let’s say this is on my right eye. Your eye is going to flip in towards your nose, and your left eye is going to do a yoked movement, because they like to work as a team. So your left eye will also move out. But it doesn’t want to see double, so your eye will refixate so you see single. And that’s a very normal response. If you have amblyopia — I’m sorry, microtropia — and you introduce the four base out, your eye isn’t gonna realize that you’ve shifted the image, because the amount of shift is less than their microtropia. So because of that, you’re not gonna see any change in the eye movements. If you are now introducing… This is my amblyopic eye, this is my normal seeing eye, and I introduce the four base out in this eye, this eye notices a shift, and because there’s a yoked movement, our eyes like to work as a team, your right eye will also move, but it won’t refixate, because it doesn’t see double. Worth 4 dot at distance and near. You would have a normal response, so they would see all four lights, but as you get in the distance, let’s say my right eye is my microtropic eye, my left eye has the green lens on it. When I get to 10 feet, the patient will only see the three green as opposed to the two red. That’s because, remember as I said really early on in this presentation, patients have a normal peripheral vision. So when I’m really close to the patient, so that’s within 3, 4 feet, the angle that the worth four dot is subtending on the retina is beyond the microtropia. So they can fuse that. Whereas when I get further away at 10 feet, the angle that it subtends is within the suppression zone of the microtropia, so they suppress and they give you an answer of suppression. And then they would also have no RDS, because they’re not bifoveating. So just keep that in mind for patients who are not responding. I do think I also have to talk about the future of amblyopia treatments and the news research, what is happening. Birth et al. had done a binocular treatment for amblyopia, where they were doing iPad treatment in preschool treatment. There was evidence to support a role for binocular visual experience in the treatment of amblyopia. They were using dichoptic iPad games. They had red/green glyphs, with high contrast in the amblyopic eye and lower in the dominant eye. They would adjust the images so they would see in both eyes and adjust the contrast to help eyes become more binocular. They had 50 amblyopic children, playing the games at least 4 hours per week for 4 weeks, and there was a placebo group, regular iPad games without the dichoptic portion of it. So the placebo group had no significant improvement in visual acuity. The treatment group, the mean VA improved about one line at four weeks, and similar improvement despite the type of amblyopia. The children who played greater than 8 hours of the iPad games per week had significantly more visual acuity improvement than those who played 0 to 4 hours, but there was no significant improvement in stereopsis between the two groups. PEDIG is on ATS18, looking at patients 5 to 16 with anisometropic or strabismic amblyopia. So they had 5 to 12-year-olds, the study design is testing the hypothesis that binocular treatment of iPad games for one hour a day was not inferior to patching for two hours a day. And what they really found was that there was no proof that patching is more beneficial than refractive correction alone for children ages 13 to 17. The study design assessing the hypothesis that binocular treatment with iPad is superior to patching. The duration is 16 weeks, but they’re still recruiting for ATS20. Compliance… So why is compliance poor? We have to keep these in our minds, when we’re talking to our patients. It is associated with poverty or social deprivation. Parents not understanding the treatment. When there is no improvement from the treatment, the patients are less likely to be compliant. When there’s only a mild anisometropic amblyopia, so for those patients who are plano and +1, a lot of those kids don’t see the need for wearing their glasses. That’s a minor prescription, so you have to really convince the parent and have them understand why you’re treating them and why it’s really important. Also for very severe amblyopes, so it’s the opposite — they’re so severe, they’re not gonna want to patch their good eye and have their best vision be 20/400. So it’s really hard to get those children to be compliant. And then older children. In regards to just poor compliance for patching, there’s a social stigma. But I think a lot of that has gone away, since we’re not patching for a full day anymore, and most of the time we don’t even have to patch for six hours a day, unless it’s a severe amblyope. So the social stigma has gotten better, because you’re patching only at home. When the parents ask me: Can the child patch at school? Can I ask the teacher to make them patch, I always say no. We don’t want kids to be teased or made fun of, so do it in the comfort of their own home. And then also skin irritation. So for the exam, the initial workup, in addition to your routine testing, obviously visual acuity is really important, and again, visual acuity with crowding is very important. For near VA, sometimes we tend to see near visual acuity be better than the distance visual acuity, despite the fact that they’re amblyopic, because when your pupil gets smaller, you have increased depth of field. So don’t let that throw you off. When you look at refractive error, you want to look at it dry and cycloplegic. If there is strabismus, remember that when you are checking their refractive error, and you’re doing retinoscopy, you want to occlude the other eye. You have to make sure the eye is aligned in the visual axis, so if there’s strabismus, I have them cover their other eye so they’re aligned. You want to check cover test, stereopsis, and fixation status, and again, dilation and everything else you would normally do. And on the return visit, after they’ve been wearing their glasses, their history is aimed at probing compliance. You want to lensometry the glasses to make sure they’re correct. I can’t tell you how many times they’ve come back and the glasses have been wrong. You want to repeat visual acuity at distance and near with their glasses. I don’t check it again without. I always do a dry retinoscopy, I don’t dilate them on repeat visits. I do it over their glasses. If you take glasses off, they’re gonna be accommodating. So you might as well just check retinoscopy over glasses, to make sure they’re close to neutral. Repeat cover test with glasses on, repeat stereopsis. Hope that it has improved. Repeat fixation status, check accommodation and ocular motor measurements. Like we said before, amblyopia is not only decreased VA. You do see a lot of other deficiencies. And so you want to make sure if you need to train that or do vision therapy, that you do. And I always repeat cycloplegia before any glasses changes that I make, or if improvement stalls. I’ve had examples where I’ve had a patient come back, and if improvement isn’t really increasing the way you would expect, maybe I didn’t get a good response the first time, they didn’t fully cyclo, maybe you’re seeing a latent hyperopia now that you’re giving some of their hyperopia, there are a lot of reasons why that is important. So that was my last slide. Thank you. I see that there are a lot of questions. So let me see if I can answer some of them for you. I’ve included my email address for you as well. Feel free to email me, if you have additional questions. Hold on. Just as a quick definition, what does NLP and LP mean? I’m sorry for using abbreviations. NLP would be no light perception and LP is light perception. Okay, there’s about 30 questions. So I’m trying to scroll through as many as I can, to see what the easiest would be to answer. I definitely won’t be able, I don’t think, to get through all 30 questions, but I’ll answer a few. I think this is a good question. How to effectively manage an amblyopic patient in an independent practice. I don’t think that anything that I discussed today would stop you from being able to manage amblyopia in an independent practice. I don’t think that you have to be at a teaching institution or at a vision therapy practice or anything like that, to treat amblyopia. And so I don’t know how it works in other countries. But if you have access to having patching — one thing that’s also really nice… Well, one type of patch that we sell in the United States is called Ortopad, and I don’t have any financial disclosures. I should have said that in the beginning. But there’s a patch called Ortopad. They sell them on Amazon, but they also sell them at our local pharmacies. And they are really kid-friendly. And so they have, like, pictures for kids, they have little puppies and race cars, and flowers. So they’re really fun-looking patches. So it gets the child a little bit more excited. And they also sell — Ortopad, the same company — sells these posters, and they’re really cute, and I think it does help kids to get more excited for it. It’s a poster that has, say, a giant truck, and the wheels are all in the shape of patches. So every single day that they’re done patching, they put their patch on this poster, and by the end of, let’s say, three months of patching, they’ve created this really pretty picture with all of the patches that they’ve used every day. I don’t know as far as atropine — I’m sure it’s accessible. 1% atropine should be accessible in most countries. But like I said, I don’t think anything I’ve discussed today should hinder you from treating these patients in your own practice. So if the patient is anisometropic and I keep the anisometropic the same, how would I expect the improvement to be? This is just based off of the amblyopia studies that I discussed earlier. You would still expect the 2 to 3 line improvement, if you just look back at the ATS studies. They’re really helpful in letting you know what the prognosis should be. What is the ideal time to refract the child after starting patching for amblyopia? I refract that patient on the first visit. Before I’ve prescribed and started patching therapy. But I do dilate and do a comprehensive exam on an annual basis. The only time I re-refract the child is if I cyclo again, because I do think there has been some plateauing in the treatment. If there is an effect in amblyopia treatment for anisoconia… I think that’s a really great question. With kids, I’m not as concerned with the anisoconia when they’re young. They do adapt really quickly. I’ve never had a child be like… I’m really off and not improving in vision because of it. Because they’re so blurry in that amblyopic eye. The concern is to just give them the glasses. But I do think there is room for conversation for: At some point, when do you want to give contact lenses? Maybe there’s more argument to give contact lenses in a patient who’s plano and -10, because if you think of the lens difference, the -10 is gonna be very heavy, it’s gonna look different, the child would get made fun of and we never would want that. But I think that in those cases, a lot of times a child who is a plano and -10, their -10 eye is 20/400. And if they’re 20/400, you don’t want to put a contact lens… Well, I should use a different example. Let’s say they’re 20/30 and they’re a -2 and a -10. 8 diopter difference. So it’s gonna be tempting to want to give contacts in both eyes, but I would argue never to put a contact lens in that 20/20 eye. Because God forbid something happens and they get an infection in the good eye from the contact lens. Then if they get an infection in this eye, and the best corrected vision is 20/400, they’re set up sort of worse in the future. So I always try to stay away from their better seeing eye getting a contact lens, because I don’t want to put them at risk for an infection later. But what I might do in that scenario is give them the -10 contact lens can being obviously you would have to adjust for everything else for the lens, but give them a contact lens in that -10 eye, and then put the rest of that prescription in a pair of glasses. That way you’re also forcing them to wear glasses, which is really important in protecting the vision of that good eye, because there are studies that show that there’s a higher chance of having something sort of — trauma happen to their better seeing eye when one eye sees really poorly. I hope that makes sense. So what will be the advice during atropine therapy, and what are the tasks in refractive correction that should be done during it? For all types of patching or atropine therapy, you’re prescribing the same. That doesn’t change. As far as advice, I think that it’s important that you’re educating the parent on the side effects. So letting them know that they will have increased light sensitivity. Sometimes while we did say that weekend therapy is good enough for atropine for these patients… I would tell the parents: Whatever works for you to remember. So sometimes what would help a parent remember better to instil the drop would be every other day. Maybe it is helpful for them to just remember Saturdays and Sundays. Maybe they have something that they do on Wednesdays and Fridays and they want to choose Wednesdays, Fridays, and Saturdays. So whatever works with that patient to remember that they need to instil the drop. But you also have to remember: If a patient has really poor vision, let’s say they’re 20/400 and 20/20. The way atropine works is you’re making the good eye blurry. So it’s really hard to get the vision poorer than 20/400, even with atropine. So you have to make sure that the vision, after using atropine in the better-seeing eye, if this eye is a severe amblyope, that you can get the vision to be worse than this amblyopic eye. The point of atropine is that you’re making the eye blurry enough that they’re switching the use of which eye. If they’re using their amblyopic eye, that’s what is getting the treatment better. So that’s something that is important to keep in mind. I think a lot of these questions I’ve answered along the way. So there’s a question for adult amblyopia, will you recommend performing a 30-2 Humphrey visual field when you’re first seeing the patient? I think that adult amblyopes are a little bit harder. One thing you have to make sure of is that the amblyopia is truly from an amblyogenic factor. There are so many things that can influence them. Especially if they’re a refractive amblyope. Did they have cataracts, cataract surgery, myopic or hyperopic shift? Did their prescription change from medications they’re taking for diabetes or some other disease? So you do have to do whatever battery of test you feel like you need to do, to rule out the fact that… Again, it’s an inclusion and exclusion diagnosis. So you have to do whatever you think you need to do, based off their findings, to make sure that it’s truly amblyopic. So again, this is more of… I’m sorry for using abbreviations. RDE and RDS in stereo is random dot E. It’s just the type of stereo books we have. The one we have is the random dot E, where there are squares and they have to show, out of four squares, what are the pictures they see within the square. That would be RDS. RDE would be random dot E. So there are Es and they have to see where there’s an E out of the two. So you have an E and a regular stereo, and they have to see which has the E in it. Sorry about that. So our brain can compensate for 1 to 3 diopters. Why are we considering it amblyopia? When you are giving them the pair of glasses on the first visit — does their vision improve? If their vision improves on the first visit, and they’re 20/20 in both eyes, they might have an amblyogenic refractive error, but they’re not amblyopic if their stereopsis is good and their vision has improved to 20/20. But as an adult that has normal vision — their brain can compensate for anisometropia. But it can’t compensate when you’re talking about having the brain be able to see a clear image. So you have to do the proper testing to ensure that they have not — that they don’t have that clear image on the retina, their vision does not improve even with correction, and stereopsis is reduced. Because that means they’re not compensating, and you do have to treat them for amblyopia. I think for an adult amblyope, again, I think this is a different… How can you treat an amblyope who’s an adult? This is a very different ballgame. There’s a lot of research that is going on right now, to see how you can effectively treat an adult. Like I said, the studies that we have right now… Are up to 17 years of age. I think if you have a motivated adult, it wouldn’t hurt to try patching and vision therapy. Again, I’m not talking off of a specific study, but I do know that there are other studies happening, to see how you can potentially treat an adult amblyope. And one thing that I didn’t mention, which also I think is going to really influence how we’re treating amblyopia in the future, is virtual reality games and tests. So there are a lot of virtual reality or VR types of treatments that could change how we treat amblyopia in the future. I have a very different clinic than I think most people. So what is the gross prevalence of amblyopia at my clinic, and what type of amblyopia do I encounter the most? I see only pediatric patients, and I’ve been seeing primarily pediatric patients for the last ten years, almost ten years. So I see, I think, a higher prevalence. But in general, I know that the prevalence is 1% to 3% of amblyopia — exists. And it depends on the population that you’re seeing, of course. If there’s any developmental delays or other syndromes, you might have a higher percentage. I do see children with special needs as well. So I would say that my prevalence is higher than most people. I don’t fall into that normal 1 to 3%, because I see pediatric patients all day and I do get a lot of referrals for amblyopia. What type do I encounter more? I would say I encounter refractive amblyopia the most, a mix between anisometropic and bilateral amblyopes. I have always worked in different cities, so I see a lot of different ethnicities wherever I’ve been practicing, and that’s influenced the type of amblyopia that I’ve been seeing. In the case of video games, for how much time would we advise to play with the patching and the correction? I would say… If you’re patching only for two hours a day… This is more of a holistic approach. I don’t know if you want the child to really be playing a video game for two hours a day, every day. I think it’s important to have them do a variety of games and tests and homework and mazes and word searches and whatever else. I wouldn’t want my child to play video games for two hours a day, every day. But I don’t have children, so I don’t know how much I would have to bribe them to do the patching. So I do think that that question is a little difficult for me to answer. But I would try to limit the amount of time they’re playing video games every day. So this question is a very specific question. I saw a 7-year-old patient with an amblyopia in the left eye with an esotropia and inferior oblique overaction. Is it possible to treat this child? Yeah. You can prescribe the full plus. The inferior oblique overaction shouldn’t really play a role. I think that’s really typical, seeing an inferior oblique overaction with a child who has an esotropia or if they have a congenital esotropia. I think it depends on the type of esotropia that they have. If it is truly a congenital esotropia, I think a lot of times those patients do a lot better with surgical management. But if it is not a congenital ET, and they have a lot of plus, you can try prescribing the full plus first. If they don’t improve, maybe it’s more of a congenital and they have to do the surgery. So it depends on the type of esotropia. I’m gonna answer one more question, because I think we’ve gone way over time. So what would the regimen for patching in a unilateral pseudophakic 2-year-old be with very deep amblyopia, VA of light perception with inaccurate projections? This is severe amblyopia. For those patients, when they’re young, you’re essentially patching any waking hour. Which is almost 6 to 12 hours a day. So this is a very different type of example. But when they’re infants, you’re patching for all waking hours. Because they’re not awake for 18 hours a day. As they get older, though, you want to patch them as a severe amblyope. I know some ophthalmologists that I’ve worked with in the past have also done atropine and patching therapy as well. But for these kids, with deep amblyopia, you’re trying to patch them for as much as possible. I’ll do one more. I feel bad. I want to answer as many as possible. I wish I could get to all of your questions. So frosted glass… There is a research, ATS research, that has looked at Bangerter filters, and that goes along with frosted glasses. There are other types or ways that you’re considered patching that are not the traditional ones that I’ve discussed. There is room for Bangerter filters or other ways of occluding a patient that are not just a traditional patch. One thing I didn’t discuss, that I don’t know if it exists in other countries, is that there are types of soft patches that go through the temple of the frame and over the lens. They’re not a sticky patch, but they’re a patch that they put over their glasses. I don’t ever use that as my first line of patching, because I do think it’s really easy for a child to cheat. You just have to move it to the side and peek through. But I do think it’s a good option for parents who come back and are like… We patch, but they hate it. They’re really good about it, but they really hate the stickiness of the patch. Then I might recommend the patch that does go through the temple and over the lens, because I think it’s a good option for some of the kids who really hate the patch but are compliant with the patching. Do I ever correct the refractive error in the good eye or only full correction in the amblyopic eye? I’m basing it off of the prescription in both eyes. If I’m cutting a prescription, I’m cutting it in the sphere in both eyes and I do so equally. I think that… I think that it’s really important in amblyopia treatment that you’re giving the proper prescription. If you’re not giving the proper prescription, then the retina is not getting a clear image, and the same input in both eyes, the way they’re supposed to, and so if that’s not happening, then your treatment, even if you’re patching, or even if you’re doing atropine, it’s not gonna be as effective, because you need to have a clear image on the retina in both eyes for it to work. Or to be effective. So I think that this question… It really goes along with everything that I’ve discussed. Giving the proper prescription is very important in the treatment of amblyopia. This question may have… So this question was: Is patching treatment effective for a 14-year-old patient? This is gonna be the last one I do. Is patching treatment effective in a 14-year-old patient? This really goes along with the ATS study that talks about the 7 to 17-year-olds. You know, they broke it up into the two different groups. So it can be effective. You have to ask them if they’ve had any prior treatment. Of amblyopia. And at that point, you can give them glasses and a patching regimen, to help their treatment. There’s been a few questions about nystagmus in amblyopia. Again, that’s a very different animal. To talk about. I think that in that case, a lot of patients — so this is really my last question. I know I’ve said that ten times. For nystagmus, one thing you want to make sure is if they have a latent nystagmus — does their nystagmus get worse when you’re occluding their one eye? Because if their nystagmus gets worse with occlusion, then you might want to stick to an atropine therapy, because then you’re not having to deprive their eye, so you’re not making the nystagmus worse. By doing the patching therapy. Also, with nystagmus, it really depends — I might put those kids in a contact lens. Because there is some research to support the fact that there’s a good biofeedback mechanism when they have a contact lens. And their nystagmus might dampen with that contact lens. And so again, the goal is very different. I think the prognosis will be very different. And I think that I would try to make sure that the proper treatments that you’re using also don’t make the nystagmus worse. But know that the prognosis will be different in these cases. I hope I’ve helped. Again, you can email me if you have a question that I haven’t answered. I’m happy to answer your questions. Thank you so much for all of your time, and for listening to me.
September 19, 2019