This live webinar talks through the steps of trial frame refraction, including the use of a Jackson Cross Cylinder, in patients of all ages. The webinar also extends to different charts that could be used during refraction, different techniques to identify astigmatism and adapting a refraction to suit individual patient needs.
Lecturer: Dr. Sarah Wassnig, B.Optom, MPH, New England College of Optometry, Boston, USA
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DR WASSNIG: Hi, everyone! Thank you for joining us today. I am an optometrist, and I work here at the New England College of Optometry, which is where I’m currently streaming live from this morning, and I work with Orbis International on their optometry programs. Today we’re gonna be talking about trial frame refraction. I am an Australian optometrist, and I was trained at the University of Melbourne, where trial frame refraction was just as important as phoropter refraction. So when I graduated, I was expected to be as proficient and efficient on both techniques. When I graduated, a joined a practice that only did trial frame refraction, which in Australia is not that uncommon, and so today a lot of the tips and tricks that we go through will be thanks to a mentor and a great friend of mine, Ian Clemens, who was my first mentor when I graduated. So let’s get started. So we have a couple of objectives today. We’re gonna go through the steps of trial frame refraction. But there was a webinar a couple of weeks back from Diane Russo who went through subjective refraction in more detail than I’m gonna go through, so if you haven’t watched that webinar, I strongly encourage you to go back and download or watch it online, her webinar. Also later in the week, by the end of the week, we’ll have a handbook up online in the library, detailing the steps of refraction for both subjective refraction in a phoropter and in a trial frame, so you’ll have those for reference as well. Today we’re gonna go through why trial frame is different and how it changes and how you can adapt to your refraction technique to achieve everything you would want to in a phoropter. And then at the end, we’re just gonna go through a few challenging patients and testing environments. We have a lot of questions — both Dr. Russo and myself had a lot of questions coming in on specific patient refraction questions and altering or adjusting our refraction for a prescription. I am not gonna address that today. My team here at the New England College of Optometry are working very hard to get those types of resources to you, so keep a watch out on Cybersight, and we’re hopefully gonna have some patient cases and help you with those refractive difficulties. But in the mean time, though, I do want to just direct you — if you are on Cybersight, and you do have specific patient questions, I just want to direct you either to the cases, and so you can start a case, you can see them circled in blue, if you want to ask a specific question with specific case details, if you want to ask one of our doctors here, or jump on our discussion board. We have two discussion boards that we’re part of. Refraction, glasses, and contact lens forum, and the smart technology forum. We’ve got doctors here who specialize in low vision, pediatrics, general refraction, contact lenses. So please jump on. We want to hear from you. I am going to briefly cover a few things today. I’m gonna just… Cover a few things today. I’m gonna cover low vision patients and refraction in a trial frame. The reason that I’m covering this is it can get a little bit different, and a little bit tricky with your trial frame, and that’s often the reason why people say: No, I don’t want to trial frame refract those patients. They’re difficult. But I’m not gonna go through the details of the techniques of retinoscopy. We do have some great webinars on those subjects, so if you’re interested, go to the library and check them out. If you’re not yet part of our community, please join us. You can see on the Cybersight website there you can join us. If you are joining us, make sure you click “I’m here to learn”, and “Yes, I’d like to receive expert advice”. That’s where you get involved in the chat discussions and the telehealth platform. So to get us started, this is actually for me — and we’ve got quite a few people participating. We’re up to 60 at the moment and have 400 registered. So I want to get an idea of who is out there and how many people are trial frame refracting. So how many people trial frame refract? A, I never trial frame refract, B, I trial frame refract, but only for low vision patients. That’s very common here in the US. C, I sometimes trial frame refract, if I have to, and D, I only trial frame refract. I don’t use the phoropter at all. So we’ll see if anyone’s out there. Anyone’s awake. Great. So that’s really fantastic. We have a lot of people out there who are trial frame refracting. That’s fantastic. Our next question for today is how many people learned how to do a full trial frame refraction in their degree. A was no, I was only ever taught phoropter refraction and when I got out, I had to sort of make do and learn myself. B, I was taught only trial frame refraction. That’s the only type of refraction I was taught. C, I was trained about equally, similar to myself, in phoropter and trial frame refraction. And D, I was only trained in trial frame refraction in the context of low vision patients. So again, here in the US, that’s very common. That we only teach trial frame refraction for dealing with low vision patients. Okay, nice. Fantastic. Fantastic. Okay. My last question is gonna be: How many people refract in environments outside of my clinic? A, it’s only in my clinic or the hospital that I’m working in, B, I sometimes go out to community screenings, but I don’t do full refractions, just screenings. And C, I visit remote towns or nursing homes, school halls, we set up, and we do a full eye exams and full refractions. Okay, very cool. So thanks for indulging me in that. I just wanted to get some information about who I was talking to. They’re gonna be our last poll questions. We’re gonna try something a little bit different with Cybersight today. They’re our last poll questions. What I do want you to do, though, is use the Q and A, which is down on the bottom of your screen there, or might be up on the top corner. If you have a question, please type it in as we’re talking. I want questions like… I don’t understand what you just said. I don’t understand that exact technique. Could you go over this exact step again? Those kinds of questions. Questions that are more specific about patients or about patient care — then pop those on Cybersight. We are always there. We’re available on Cybersight. We want to hear from you. So pop those up on our discussion boards. If it’s something that I think we’re gonna address later, then I’m not ignoring your question. I’ll just keep moving on. So please type in questions as we’re going along. So how is trial frame refraction different to a phoropter refraction? Don’t get me wrong. I love the phoropter. And so I’m by no means dissing the phoropter. It is very efficient. And I would say that a lot of people would say that they’re more efficient on the phoropter, and it’s fantastic. It gives you a broader scope of tests and lenses that are readily available, and so it can be a little bit easier to perform some tests. However, there are a few times where it’s just not practical. In young children, for example, they like to see who they’re talking to, see your facial expression. It could also be quite scary behind the phoropter. And sometimes they can be a little bit too short, and you can’t quite get the phoropter down. Also, in the elderly, sometimes — especially if they’re hard of hearing — then they like to look at you when they’re talking, and a trial frame really allows for that. It also means you don’t have to watch or see if someone’s going and pushing back or off the phoropter and so your vertex distance is changing. It’s also really useful for patients with disabilities. So if you have a mental disability, then they can… The patient can communicate with you, and can see your facial expression, and if your patient has a physical disability, then you don’t have to get the phoropter down as far. You can also — if they’re in a wheelchair, and you can’t get them up on your chair, then a trial frame is really perfect for those kinds of patients. Also, another really good set of patients is patients with low vision. They can see what’s going on. You can see what’s going on. People who speak a different language to yourself, because there’s a lot of miming going on during refraction. And people who have high prescriptions as well. Trial frame refraction is great for that, because you can control the vertex distance and make it very similar to the vertex distance that you’re going to prescribe with their eyeglasses. The best thing I love about trial frame refraction is everyone can do a trial frame refraction. Every patient suits a trial frame refraction. There are some patients that the phoropter doesn’t. So it just saves me from thinking… Oh, should I or shouldn’t I do trial frame this time? So we’re gonna go through the equipment that we need for a trial frame refraction. First off, the trial frame itself. You can see there’s lots of different types. But they all have a few things in common. The first thing is: At the front here, they have a well where you can put your lenses in. And so there’s usually three or four spots where you can pop the lenses in. You can also see they all have numbers around the edge, which tell you where your cylinder axis is, so you can line your cylinder lens, and they’ve got a little knob on the side that rotates the barrel of those three lenses, so you can rotate the lenses to match the axis that you wish to move it to. They also have a well — some of them, a lot of them — have a back lens well, either one or two spots at the back. This is really handy to put your sphere at the back, and it’s also very helpful if you have a high prescription, because that again lowers that vertex distance. A lot of them have adjustable temples, and so you can adjust the temple for the side of the patient, so it’s nice and snug behind their ear. A lot of them have an adjustable nose bridge, so you can see here the knobs at the top of this one here — it adjusts it up and down. Some of them have adjustable PDs or pupillary distances. So you can adjust it on a monocular scale. The lens set itself — I’ve got a lens set behind me here that we’re gonna be using today. They come in lots of different shapes and sizes. You can see some of the lenses have metal rims, and some of them have plastic rims. They’re all the same. You’re gonna see lots of them today. Lots of different types today. Okay. So the next set of equipment I’m gonna point out is your JCC lens. We’re gonna be using this a lot today. It’s something that people have a little bit of trouble with, so we’re gonna go through the JCC lens. Often they can be purchased with the lens set, but often they’re purchased by themselves, in a little container such as this. So you may have to purchase your JCC lens separately. You’ll also see in your kit you’ll have a red filter and a green filter. These are your red and green filter lenses here. You’ll have an occluder in your kit. It’ll be somewhere in this part here. That occluder just means you can keep the prescription in the eye that you’re not testing. You can just pop in that occluder and block off the vision, so you’re testing one eye at a time. We have a stenopaeic slit. I’m sure I’m pronouncing that incorrectly. This is an old way of testing for astigmatism, but we are gonna go over that today. Because it can be handy at times. Though not exactly as much as JCC. You have a pinhole occluder in your set as well. So the pinhole is really useful if you want to know if your low visual acuity is due to refractive error or if it’s due to pathology. So it works similarly to a pinhole camera. When you put it in front and the patient looks through that tiny hole, it eliminates the refractive error and it focuses the light at the retina. Hopefully you get close to 20/20 vision then, and then you know — okay, it’s refractive. I didn’t get my refraction right. So it’s a good way, if you’re not getting the visual acuity that you think you should be getting, pop that pinhole in and see… Is it you and your refraction method? Or is it actually pathology? Because if you put that in and it doesn’t change, they’re still getting pretty poor vision, then you know there’s some pathology behind there. Maybe some cataracts, maybe some macular degeneration, optic nerve issues, things like that. You have a Maddox rod in your set. This is a red one. You’ll sometimes have a clear one. They all do the same thing. We’re not gonna go over the Maddox rod today. Dr. Geiser has a webinar coming up in Jun has a webinar coming up in June, and she’s going to go over that technique. We also have some prisms. Again, we’re not gonna answer any questions or go through any patient cases with prisms. Dr. Geiser will be using prisms in her lecture, so it’s good to know where your prisms live. Just on a side note for her lecture a little bit later, you can get loose prisms as well, if you want to work with your trial frame, but you want to do some of the tests that she’s talking about, particularly Risley prisms. She’ll go through the use of Risley prisms. You can get little ones that sit into the trial frame, and you can do those Risley prism tests. You can also get handheld ones that can be really helpful. So that’s just a side note for when you watch her lectures in June. So on the left hand side here, you have your negative lenses. If they’re plastic, then they’ll be in red. Always in red. Negative is always red. And positive is usually black or white. In optometry. And so you have your negative lenses. You have two sets of lenses. They’re identical. They go from about 0.25 to up to 14 diopters, and they go in various steps. Sometimes 0.25 steps, sometimes 0.50. It depends on the set. Over on the right hand side, you have your positive lenses. Again, you have two wells of identical sets of lenses. And at the top, you have your cylinder lenses. You can see that actually my cylinder lens is on the right hand side. I’m not quite sure if you can see that. It’s empty. In optometry, we work in negative cyl prescriptions and refractions. So that’s what we’re going to do today. So I’ve removed those lenses from my lens kit, because it’s annoying to have them there sometimes. I grab the wrong lens by accident. But if you work in positive cyl, the theory is just the same. It’s just that you’re working in positive cyl instead. So how do I work with a loose lens set? And there’s a few tips and tricks to make it more efficient. First off, keep it tidy! The worst thing you can do is have a bunch of lenses in this middle well here. That is the worst thing you can do. It is so incredibly tempting as well, but you really do need to keep it tidy. When I was at school, if I got caught with multiple lenses in this center part here, I believe that I lost some points from my patient, and fair enough as well. The problem with having so many lenses here — it takes you time to put them back into your lens set, and that’s just not time in your day that you have, if you’re in a busy clinic. Even if you’re not in a busy clinic, it’s just not time that you have. From patient to patient, you want to be very confident that you’re pulling the right lens out, and you don’t want to be searching through this center case during your refraction. It really slows your refraction down. The second thing is: Keep your fingers off the lenses. When you’re pulling them out, use the little handle that’s supplied. You don’t want to be grabbing the lens from this inner lens. You don’t want to be cleaning it all the time. Every time you clean it, you waste a couple of seconds, and that’s not a couple of seconds you have in clinic. You’re saying… Yeah, but what if I want to reserve a lens? What if I’m using a lens and I think… I’m gonna come back to that? That’s a fair point. I completely understand your concern. But rather than be tempted to put the lens in this well, I still want you to put the lens back. But when you put the lens back, just flip it into the center. If you flip it into the center, then if you want to come back to it a little bit later, you don’t have to search through that middle section looking for it, so you don’t have to waste your time doing that. You can just run your finger down the center and grab the lens that you’ve reserved, or that you’ve flipped into the middle. This way, if you don’t end up coming back to it, then that lens stays in its spot, and you don’t have to clean up at the end of your refraction. Also, if you do end up coming back to it, it’s easy just to grab, and you know which one that you’ve reserved. So don’t be tempted to put it in the middle. Also, when you’re working with a lens set, it’s really helpful if, when you’re taking lenses, that you take lenses that you’re in the right hand side of the well, just say we’re looking at positive lenses here… If we take those lenses and put them in the patient’s left eye, so your right side, and take lenses from the left side and put them in the patient’s right eye, or on your left side. It just means two things, actually. It means that when you’re putting lenses back, and you’re in the middle of the refraction, you don’t have to go back and see… Ooh, where exactly did that come from? Also when you’ve finished your refraction, it’s really easy just to pop them back, because you know anything from this eye came from this side. So you just find a gap in your lens set, and you know that’s exactly where it lives. Use the gaps as a reference to put them away. So if you have a full lens set, make sure you’ve always got a full lens set. If you’re missing a couple of lenses, they’re actually really easy to order with the company that your lens set is from. You can order just a +2 if you’re missing a +2. But when you’re missing a lens, I don’t have to look very carefully at where to put the lens back. I can just run my hands down and pop the lens in that gap. So I don’t have to think about it that much. It’s also really helpful when you’re doing retinoscopy. So let’s go over refraction. First you want to test the patient with their glasses on, or if they have no glasses, just as they are. You want to do this with the full chart and test both eyes individually and binocularly. For two reasons. The first is for legal reasons. You don’t want people coming back and saying… You’ve ruined my eyes. You made them worse. So you documented before you even started what their vision was. The second reason is: It gives you an idea of what their best visual acuity may be. If they’re reading 20/20 in their current pair of glasses and you’re doing a refraction, and you can’t get them below 20/30, then you know that something is not quite right, because you know your refraction must be incorrect, because in their glasses, they were seeing quite clearly. Also it gives you an idea about their management. If they’re seeing 20/20, that’s great. Probably you might tweak their glasses, you may not. If they’re seeing 20/40 in their glasses, then I’m thinking… Okay, I do need to prescribe them glasses at the end of this. So it just gives you an idea about how you’re gonna proceed with management, before you even start. When patients are reading the chart, interestingly enough, they read just above their best corrected visual acuity. I think most times people just don’t want to make a mistake, which is fine. It’s fair enough. So you just need to keep pushing them. So if they read the 20/20 line, say… Look, that’s great. Can you read any of the letters on the next line below? They might be able to say… Oh yeah. I see a C, E, and a K, and then something-something. So then you know they’re 20/20 plus 2 or plus 3, depending on if they got those letters correct. So reassure them: It’s okay if you’re wrong or if you got anything incorrect, but just keep trying for me. So how are we gonna set it up? First of all, we want the patient sitting comfortably and we don’t want them leaning forward. So that’s one thing the phoropter does stop people from doing. Length forward. leaning forward. Particularly kids, who shuffle up in their seat. So people always want to try to do the best by you. So keep reminding people to sit back nice and comfortable. Your illumination depends on your chart. If you’re not using an electronic chart, then you need good, bright illumination throughout your room. If you’re using an electronic chart, particularly some of the charts that are a little bit older, you might have to dim the lights to get that contrast. And you want to be off to the side of the patient. You want to be able to manipulate your lenses, but you want the patient to be able to see straight through, above your arm, to the chart that’s behind you. Just on a side note, when someone is talking about leaning forward and squinting — when someone is reading visual acuity, it’s always important to keep watching the patient, rather than watching the chart. You want to know your chart off by heart. Because if the patient is leaning forward and squinting and you’re looking in the opposite direction and they’re reading 20/20 and you turn back around, you go: That’s great! That’s fantastic! They’re not actually reading 20/20. They’re squinting to make that happen. So you need to watch your patient to make sure that they’re not cheating or trying to do a little bit better by leaning forward or squinting. So know your chart off by heart. Okay. You also want to make sure that the trial frame is adjusted. So you want to make sure that the temple is straight. You want to make sure that it’s not bent. You can see that the tilt on the left hand side is changing the tilt of the trial frame, and it’s also probably gonna make it a little bit crooked as well. And you want to make sure that it’s nice and snug behind the ears. When I’m putting my trial frame on, I always tell my students — particularly if someone has long hair or if you’re worried about catching their hair, to find the patient’s ears just with the top of your fingers here, find their ears, and help them put the trial frame over top, and then shorten the temple, so it fits up against their nose. You want to make sure your frame is straight. And we had a question in the prequestions that came through. Why is this important? And it’s a good question. But it’s really important. If you end up prescribing cylinder or astigmatism that is just a -2, and the frame is like this, when you prescribe that, you’re gonna get the axis wrong. So then when you prescribe it and you put it into your system and they get their glasses, they’re gonna put their eyeglasses on and say… I can’t see anything! You’re gonna say oh, that’s really odd. The prescription in the glasses matches the prescription in my computer, or on your file. But what you haven’t taken into account is that your trial frame was very, very crooked. So you want to make sure that your trial frame is straight. And also a lot of people have a lot of facial asymmetry. So you want to make sure that trial frame is not only straight, but it’s straight with the eyes, and with where your eyeglasses are gonna sit. So maybe if your eyes are a little bit… Maybe one is higher than the other, you just want to be mindful of that. You want to make sure that the pupil distance matches the patient’s pupillary distance. So you can see in the middle there that it’s way larger for her face. So we need to bring that in. And you also want to make sure that the nose rest is right on top of the nose. Some of these can be really uncomfortable. If you have a trial frame that patients complain a lot about, sometimes putting a little bit of a tissue here or cotton wool is helpful, just to relieve the pain or the red mark on the patient’s nose, after you’ve finished refracting. They might complain a little less with some cotton wool. And make sure again that the patient is looking through the center of the lens. Okay, so we are coming up to a set of questions. I can see I’ve got a few questions coming in, which is great. So if you’ve got a set of questions so far, you’re thinking — she’s crazy. What is she talking about? We can go over some things together. So where do we start? We have three options, and to be honest, I don’t mind which option you go for. You have retinoscopy, where you objectively see what the prescription is, you have an autorefractor. A lot of clinics autorefract their patients before they even get into your rooms, which is fine. Keep in mind that accommodation affects this a lot. Affects the autorefractor a lot. It assumes you have a normal lens and a normal corneal shape. So if you have some keratoconus or cataracts, your autorefractor isn’t gonna be correct. It’s not as accurate for higher prescriptions, and the patient must have the forehead on the rest. If a tech is doing the autorefraction for you, you just need to make sure they know that the forehead has to be up against the rest. Or if you know what the previous glasses prescription is, you can just start from that point, especially if they’re seeing quite well and you’ve just got to slightly adapt it. So refraction… Sorry. Retinoscopy with loose lenses. You could use retinoscopy racks. That is absolutely fine. But you can do retinoscopy with a trial frame. It’s very easy. But you do have to stick to a couple of rules. The first rule is go in 1-diopter steps. You want to touch the least amount of lenses possible. You don’t want to be going in tiny 0.25 steps. I like 1 diopter because it’s easy to count. If you go in 0.75 steps, it’s easy to lose count, but 1, 2, 3, 4 — I’ve got that down pat. The other thing is it’s easier to do your retinoscopy and neutralize both meridians with spherical lenses. The reason is, particularly if you’re doing it in dim lighting with these lenses here, you have to sort of squint and line it up. And it takes a little bit of time to do that. So it’s better to neutralize each meridian, and then at the end taking this cyl lens here and putting that in, instead of your most negative prescription. So I’m gonna give you an example here. I’m gonna give you an example here. If we’re doing retinoscopy, and just say we’re doing retinoscopy, and I’m seeing a with-motion, first I’m gonna scan all the way around each meridian, and I think… Oh yeah, I’m scanning up and down like this, and I see a with-motion. So if I see a with-motion, I’m gonna grab that 1-diopter lens, and I’m gonna hold that over the eye. Again, still the with-motion. So I’m gonna try not to be tempted. And because my lens set is a full set, I know exactly where this lens belongs. And I count my lenses using my fingers. So I go one, two, three, and I grab the fourth one. I know that’s gonna be my +2. So I don’t have to be looking at the numbers on my lens set. So I get in and I think… Oh, you know what? I think it’s still with, but it’s close. This is when it’s really tempting to go in small steps, but don’t do it. 1, 2, 3, 4. I’m gonna hold my +3 lens over the top. I’m ready now, and I think… Okay, great. It’s against. This is really great. It’s really easy. Especially if you’re one of my students. Because they need to be within 0.75 to pass their retinoscopy. You’re within 0.75. You know it’s not +2, so it’s +2.25, +2.50, +2.75, and at 3 it reverses. So I’m gonna count down. And this lens is gonna tell me the answer. Either it’s gonna be neutral, a little bit against, or a little bit with. And I’m gonna spend my time going nice and slow, watching that reflex nice and slow. Then once I’m happy with that, I’m gonna leave that in the trial frame, and I’m gonna go to my other meridian. So I’m gonna go across to my other meridian, and now I’m scoping in this direction. And I think… Okay, great. It’s a little against. So I’m gonna pop in a -1. It’s really tempting, I know. When it’s just a little against. To go in small steps. But don’t do it. Trust me. It saves so much time for you. So I’m gonna hold this over the trial frame, I’m gonna scope across. It’s with now, so it reversed, which I was sort of expecting. Because I only saw a little bit of motion. And I’m gonna grab my 0.50 lens here, and I’m gonna scope again, this -0.50 lens. It’s gonna tell me the answer. Either it’s neutral, it’s a little bit against, or it’s a little bit with. So I see this and think: Oh, great, it’s neutral. Rather than popping this -0.50 lens, I’m gonna now come up here, and I’m gonna grab a -0.50 cylinder lens, and then I can spend a little bit more time lining it up with the meridian that I neutralized with the most negative power. Okay. So that’s how we do retinoscopy. That’s pretty much as much as I’m going to talk on retinoscopy. If you have some questions regarding retinoscopy, please post them up online, or also go back. I really encourage you to watch Dr. Bastian’s lecture on retinoscopy. It’s really quite a fantastic lecture. We get this question a lot: Do you cycloplege every patient or not? When do I cycloplege? A colleague from Cameroon sent this through, which I love. Because we had this disagreement when I was in Cameroon last. This discussion about whether or not to cycloplege. A lot of people do it in a lot of different ways. Obviously we want to relax the accommodation as much as we possibly can, so we get an accurate distance refraction. But it doesn’t mean that you always need to cycloplege. I don’t cycloplege if the patient’s age suggests that their accommodation isn’t super active. So if they’re in their 30s or 40s, particularly if they’re presbyopic, their accommodation system isn’t very active at all, then I don’t cycloplege those patients. If someone is young and in their 20s, they can take directions. So when I get them to look at a distance target, to relax their accommodation, they’re gonna take those directions and they’re gonna do what they’re told. So I’m less concerned about cyclopleging those patients, even though their accommodation might be quite active still. I don’t cycloplege if I can’t check for angles. So if I’m in an area where I’m just using a pen light to see if the angles are open or closed, then I won’t — if I’m a little bit concerned about what I’m seeing, then I’ll send them into my clinic, so we can cycloplege them there, after I’ve checked their angles. I also don’t cycloplege if I need to refract without suspended accommodation. So often in patients that don’t accept full cycloplegic well — a good example of that is my husband. I prescribed him his first set of glasses, and he hated me for a very long time, for prescribing his full prescription. It’s okay to do a little bit of work. It’s okay for accommodation to be doing a little bit of work. Not everyone needs to be fully relaxed. If people are having trouble, you might give them maybe half of their prescription, just to support their accommodative system, but you don’t need to fully relax the accommodation system in every patient. Obviously if the patient had strabismus or amblyopia, then that is a completely different story. You want to throw that full refraction, that full cycloplegic refraction at that kid. You absolutely want them to have their full cycloplegic refraction. But if the person is now 30, and they’re amblyopic… Well, I’m just gonna prescribe the refraction that makes them more comfortable. Because it’s not gonna change their state of amblyopia in any way. Also, I’m not gonna do a cycloplegic refraction if I want to do binocular testing afterwards. There’s nothing worse than a student coming in and saying: I’ve dilated this patient, and I think it’s a binocular issue. Oh, they have to come back. Because I can’t do any of the binocular testing if accommodation is suspected. So that’s another reason why I don’t cycloplege every patient. Obviously if we want to check for ocular health and you want to dilate, that’s a different story. You might want to do that at the end of your exam. There are other ways to minimize accommodation. We’ll be talking about fogging, and I know that Dr. Russo talked about fogging as well. Fogging refers to you putting plus in front of the eye to fully relax accommodation to the point where everything is blurry. Then you slowly decrease the plus in front of the eye, to the point where they can see their best visual acuity at the maximum plus. So if you popped in a +1, you keep decreasing it, when they see the best visual acuity, you’re not gonna continue to keep decreasing, because you know their accommodation is fully relaxed at that point. We’ll go over that a little bit in today’s — in the next half hour or so. But if you want to go through that in more detail, please watch Dr. Russo’s lecture. We binocularly balance patients to make sure that accommodation in one eye is not more stimulated in another. And you want to do it in patients who have active accommodation, fairly equal in both eyes. If a patient is 50, obviously they’re presbyopic, and they don’t have any accommodation, so you don’t need to worry about that. You can also use the Duochrome test, which we’ll go through in a second. So I want to look at the Q and As here, and see if there’s anything… Fantastic. I think we’ve answered all the questions. Regarding the red and green chart, we’re about to do that. Okay, good. So we want to occlude the left eye, because it’s a good habit to get into, to refract the right eye first. And you want to measure best visual acuity with your starting point. So if that’s refraction that they already have, you obviously don’t need to do that again. You did that with their glasses on. But if you did retinoscopy, then just check where their vision is with your retinoscopy. You can see with this picture here, her sphere lens is in the well at the back of the trial frame, and her cylinder lens is in the front of the trial frame. Which is handy. It means you don’t have to keep changing the sphere lens. You can make minor adjustments and at the end alter the sphere lens. But it also means that if it’s a high prescription, then it’s closer to the eye. You don’t have to worry about vertex distance, which we’ll cover just very briefly later. So you want to show the full chart. You want to make sure that you’re pushing them down to their best visual acuity. So often my students, they panic when they do the retinoscopy, and their starting visual acuity is bad. Maybe they’re seeing 20/30. And they’re thinking… Oh my gosh! That’s terrible. That’s not what I want. They’re seeing much better in their glasses! Don’t panic. First of all, not everybody sees to 20/20, and that’s okay. Not everybody can get to 20/20 vision, and that’s all right. Some of us have bigger noses than others, some of us have sharper eyes than others, and that’s just life. Sometimes there will be cataracts and things you can’t change, and again, that’s just fine for the time being. Also, trust your retinoscopy. Don’t go back and look at it again. Don’t waste your time. We know from Egger’s chart that if you’re seeing 20/30, you may only be at 0.50 diopters away from the actual prescription. So don’t panic. Just keep going forward. We want to refine the sphere. And you can see on the bottom left hand side there, you want to refine the sphere. And the way I’m gonna do this is I’m gonna point to the line that they were reading best. And I’m gonna say to them… I’m gonna show you two lenses. And I want you to tell me: Which of these lenses makes your vision clearer? So this is lens one. And this is lens two. I’m always gonna start with my 0.25. So I have a + 0.25 and a -0.25. And I’m gonna say this is one, this is two. This is one, this is two. If they say they like one, so that’s your plus lens, then grab your +0.25 from your other side. It’s okay to rob Peter to pay Paul. And do it again. Is it better one or is it better two? Keep putting in that +0.25 until they say it’s the same or now number two is better. Now the negative lens is better, so you know you’ve gone too far. You’ve overplussed them just a tiny bit there. If they really like the negative lens, I’m gonna ask them to read a little bit further. Say they were reading the 20/20 line and I say better one or two? They say oh, two! The negative lens is better. 2 is better. And I say — oh, great. Whilst I’m holding it, can you read any more letters on the line below? Or any more letters on that line that you read out earlier? If they say… Oh, not really. It’s just clearer. Then we know as the clinician that that’s just an effect of a negative lens. It makes things crisper and darker and smaller. So we’re not gonna give that negative lens. If they say yeah, I can see M, D, V, C, Z, great! Give them that minus. But if they can’t read any further, then bad luck. They just prefer that lens because it’s a negative lens. Then we’re gonna do Duochrome tests. And I’m not two worried about the fact that refining of sphere isn’t really very accurate. I’m not too concerned about that, because I’m gonna do Duochrome tests. I’m not gonna go through this test in a lot of detail, because Dr. Russo did go through this test in a lot of detail. But I do want to just say — and this actually comes from my colleagues in Cameroon. Spectacular little trick that they do. If you don’t have a computerized chart, and you don’t have a red-green chart, one thing you can do is use your red-green lenses that are in your lens set. So we have a patient here. And we’re gonna say: Is it better with the green or the red? This is the green. This is the red. And they say… Yeah! It’s much sharper with the red. So then we’re gonna add that sphere. We’re gonna add that +0.25 sphere to the patient’s trial frame, just in the front of the trial frame, that right eye. Then we say… Okay. Now this is the red. This is the green. This is the red, this is the green. And they say: The green is clearer now. We get this question a lot. How do I choose? If they say red one, and I add in +0.25, and now they say green, which do I choose? It’s okay to leave them one step on the green. When we do JCC, it’s actually easier for the patient to do the test if we leave them one step on the green. Ideally, though, you say this is red, this is green, and they say they look exactly the same. So you know you’re at that perfect prescription, and you’re gonna leave the power. Okay, so any questions before we move on? Which is better to show the patient? A line of letters or a single letter? I think it depends on the chart that you have. So if you have an electronic chart, where you can actually minimize the letters, it’s likely that you have Duochrome in there. So have a play around with your controller. Because you will most likely have Duochrome. If you don’t have a chart that can isolate letters, then in that case you’re gonna just use the whole chart, and you’re gonna direct them down to their best visual acuity, if you’re just doing the single lenses there. Okay. We had a few other questions there, but we’re going to cover that in a moment. Okay. So now we’re on to the astigmatism. This is the fun part. This is where we get to see the JCC. Okay, so you want to isolate one line if you can. And you want that line to be one step above their best visual acuity. Or if you can’t, just point to that line, and show them the line you want them to look at. Again, I’m not gonna go over in great detail how cross cylinder works. Please have a listen to Dr. Russo’s lecture. She goes over it in far greater detail. What I do want to do is just show you how the JCC lens works. So we’re gonna refine axis, and Dr. Russo goes through this, but if your retinoscopy had a cyl greater than 0.50 cyl, then you’re gonna refine your axis first. So you’re gonna align the handle of the JCC with the cylinder lens. So you can see here… Down here, this is the handle. This is where the cylinder — these are where the markings are on the cylinder lens. So if we go back, that’s where the markings are. And I’m gonna align the handle. So the red and white dots are either side. You can see here in real life, you can’t actually see exactly where the lines are, just because it’s a live photo. You can’t see where the lines are. But trust me — it’s either side of that cylinder there. So you’re going to align your handle with the lines, so you can see here I’ve got a -1.25 cyl in there. I’m gonna align the handle and I’m gonna flip. I’m gonna say which is clearer? I’m gonna give you two lenses, and I want you to tell me which lens makes that line clearer and sharper. This is lens one, this is lens two. Sometimes I’ll say — I’m gonna show you again. This is one, this is two. It’s best to advise the patient that neither lens will be completely clear, but sometimes just ask which is best. Sometimes they’ll say both are really bad, so it just saves you some instructions later on. And you just want to flip your lens just like this. Just twisting your handle. You’re going to… I’m not gonna go through this, just for the sake of time. Dr. Russo went over this in clear detail about which axis to follow. But if they prefer the minus axis or the red dots, you’re gonna move in that direction, until they say they look about the same. Then with power refinement, you want to line the dots that you have here — sorry, the lines on my JCC — on this one, you want to align those with the power of the lens. So with the axis of the lens. So again, you can see — that’s your cylinder axis there. And then I’m gonna place that lens, so in this case, this JCC has dots. You can see in the live picture, this JCC has lines. You want to align those with the cylinder axis. So this is, again, our example before. And you’re gonna ask the patient: Which is best? This is one. This is two. This is one. This is two. If they say the red dots are a little bit clearer, you’re gonna add cylinder power. So that’s more minus power to that meridian. If they say the white dots are clearer, you’re gonna take away that cylinder power. So you’re gonna take away minus power from that meridian. Once they say they look about the same, then you know that you’re finished. Again, I’m not gonna go through this in a lot of detail. Dr. Russo did in her webinar. But you want to make sure you maintain spherical equivalent the entire time. If you increase your cyl, you want to make sure you’re increasing your sphere as well. What happens if they say… If you do retinoscopy, and you don’t have any cylinder to go off, if you think… I didn’t see any astigmatism. It looked pretty spherical to me… What do you do? So this is what you do. So this is just their sphere lens. And I’m gonna ask them… Which is clearer? This is one. This is two. And you see that I’ve just flipped my lens from side to side. And I’ve essentially given them two options. Is it clearer at 45, where that red is at 45? Or the red is at 35? So they say… Option two! Okay, great. Then I remember that they preferred that axis. That 135. Now I’m gonna show them — I’m gonna orientate my JCC. So the power lines or the power dots are now at 90 and 180. And I’m gonna say… Now how about here? Is it clearer with lens 3? Or lens 4? This is 3. This is 4. And they say… Option 3! So I think: Okay, great. What I know is if they do have any astigmatism, it’s somewhere between 135 and 180 degrees. So I take my 0.50 lens from here, and I put it somewhere in between. Maybe 160 degrees. I put it at 160 degrees, and I show them, again, with my power dots: Is it better 1? Or 2? If they say 2, then I’m gonna go and do the whole JCC procedure. The whole cross cylinder procedure, because there’s obviously something there. If they say 1, though, which is the white dots, then I’m just gonna take that 0.50 out and call it a sphere. Say they have a spherical prescription. I could lower it down, 0.25, if I’m really convinced there was something there. I could do that, but they’re likely to just say that they prefer the white dots or the white lines there as well. Okay, I know JCC can be a little bit confusing. Any questions? In a child, how is this possible? It’s not, really. It’s not possible. And we’re gonna go through that in a second. If we have two different axis on autorefraction, which one do you choose? Just choose one of them and go from there. Your JCC will just keep correcting you and pushing you in the right direction of the meridian. So just choose one of them. It doesn’t make any difference to your starting point. It might mean if you choose the wrong one, your visual acuity will be a little bit off, and that’s fine. It will all work out in the wash once you’ve done your JCC test. Okay, now we’ll get to the fogging aspect that we were talking about before. You’re gonna pop +1. So remember, this left eye is still occluded. You’re gonna pop the +1, you’re gonna warn the patient that it’s gonna be blurry. Otherwise they’ll think you’re an idiot and have no idea what you’re talking about. You just say: What do you see now? And they’ll say… Nothing! It’s blurry! So say this will be a little bit blurry. What’s the best vision you can see? Maybe they’re reading the 20/40 line. So say they’ve got that +1 lens in there, in that eye. Then I pop in the 0.75, and then I take this one out. And the reason I want to did that and the reason I want to do that is I want to keep them fogged the whole time. So you say okay, where can you read to now? They can read a little bit further along. Maybe two lines, maybe just one, and I’m gonna pop this one in here and take this one out. Now where do you see to? And they might be able to read right down to the bottom of the chart. If they read 20/20 and just say they’re at 0.50, I will pop in the 0.25, take the 0.50, and say can you read any more letters below that? Or can you read that line any easier? If they can, then I’ll give them that lens. If they can’t, though, then they get the lens from before. So you want to make sure that the visual acuity is actually improving. Then you’re gonna occlude the right eye, and you’re gonna do the whole process again. We’re gonna quickly go through binocular balance. It’s a different technique. Than what Dr. Russo went through. This is called a Humphriss binocular balance. So you pop in a +1, once you’ve done full refraction on both eyes. So let’s just say into the patient’s left eye. And then just cover the eye. There’s no need to put the occluder. Just save some time. Cover the eye and say: What can you read for me there? It’s gonna be a bit blurry. And hopefully they get around 20/40 or 6/12, depending on what you’re working with. If they’re not reading — if you pop that plus in and they’re reading maybe 20/25 or 6, you want to add 0.25s here, keep increasing the power, until they see about 20/40. Then you want to take your +0.25 and your -0.25 lens here, so they’ve got the +1 lens in the left eye, so you’re gonna say… Is it clearer with lens one or lens two? If they say lens one, then you know that you’ve overminused them a little bit, and you’re gonna give them that 0.25, grab another 0.25 from here, and repeat again. Is it better one or two? And you’re gonna keep doing that until they say they’re about the same or until they want the negative. And I would go one step back, if they say… Oh, now I prefer the red. I would take out the last 0.25. Then you’re gonna pop in the +1, into this eye. And then you’re gonna take this +1 out. And the reason I want to do that is I want to maintain that fog, if I can get relaxed accommodation. I’m gonna go through the same process. Is it clearer with 1 or 2? This is 1. This is 2. If they prefer the second, then I’m going to add that minus in. If they prefer the first, then I’m gonna add that plus in. That’s a nifty little trick with your trial frame. Okay. Any questions before we move on? Okay. So we do have a question from the JCC. Why did I choose a -0.50 diopter cyl lens? The reason is because it gives you… It gives the patient something to see, if that makes sense. It gives them the opportunity to see a big difference in the two lenses. Yeah? If I popped in an 0.25, I’m just not confident that the power is high enough for them to even notice any difference. Yeah, all the time. The axis on the autorefractor or my ret is different to the subjective. Hopefully I’m good at my ret and I’m getting that accurately, but sometimes if you have a scissor reflex it’s really difficult. And autorefractors are wrong all the time. In the case of strabismus, how do we refract? We might have to cover that another time. In JCC, should we use the dots or the lines? We’re gonna go through that in a second. Do we need to binocularly balance presbyopic patients? No, you don’t, because they don’t have any accommodation left. Okay, so we’re gonna go a little bit over. I’m so sorry, Lawrence. But just a little. I promise. We’re just gonna go through some clinical pearls for refracting. I’m not gonna go over this technique. But it is outlined here. It’s written out in the notes here. It’s successive alternate occlusion. It’s another thing that you can do for binocular balance, and it’s also the technique that Dr. Russo went over in her lecture. I did want to just point out, though, you add in your plus sphere lenses, and then you’re just going to use your hand to cover it. You don’t need to use the occluder or anything like that. You’re just going to go… Is it clearer with the left eye or the right eye? This is the left. This is the right. And then you’re gonna add in the +0.25 accordingly. Dr. Russo goes over this very clearly. Have a look at the notes you can download from the library later today. She also mentions in her webinar — if you’re going to leave one eye a little bit clearer than the other, then leave the dominant eye clearer. And I just wanted to quickly go through that, of how to find your dominant eye. So you get the patient to go like this with their hands, and with the letter E that you have up on the chart with both eyes open. And you’re gonna cover one eye and you’re gonna cover the other. And you’re gonna ask if the E moves. If the E moves, then you know that you’re closing the dominant eye. So they’re seeing with their non-dominant eye. So that’s a great nifty way to identify eye dominance in free space. Steady your JCC lens. A lot of people — it’s essential that you remain on-axis. So you can see in this picture here that the lines don’t quite match up with the cylinder lines. So you want to make sure that you’re remaining on axis. That your JCC lens matches the lens of your patient. So just use your finger, if you want. It’s okay to use your finger to steady it. So you go one or two. Three or four. What if I can’t isolate a line? Or an O for a Jackson Cross Cylinder? I would prefer, if I’m gonna isolate a line, I would prefer to isolate the letter D. Particularly in older patients, it’s easier to say… I’m gonna show you two lenses. And I want you to tell me which lens makes that D look more like a D, and which lens makes it look more like an O. So this is lens one. This is lens two. And they say oh, lens two, it looks like a D, lens one, it looks like an O. So you know that lens two is the correct answer. It’s the answer that you’re looking for. I also, rather than isolate a line, I would prefer the dots. But not every chart has the dots available, which is why I went for the line in our example. But I do prefer the dots. I think it’s easier for the patient to focus on just sort of one thing, rather than a line of letters. And assessing a whole line of letters. So you would just ask the patient: Which side of the lens makes the dots rounder and darker? This is side one. This is side two. What if my patient always thinks two is the answer? This happens all the time, and I don’t know why it’s two. I don’t know why patients love the number two. So this is how my instructions go. Before I start, I say: I’m going to show you two lenses, and each time I want you to tell me which lens makes the line of letters or the dot or the D look clearer. Then I’m gonna show: This is lens one. This is lens two. If they say: Can I see that again? Then I say: This is two. This is one. So I don’t keep flicking back from one, two, one, two. It just saves a little bit of time. And they say: Okay, I like lens two. And they say: Great. Now I want you to tell me between three and four. This is three. This is four. They say four. Great. Now between five and six. This is five, this is six. So you’re making it very clear that each time the pair of lenses are very different. And then when you get to about five or six or seven or eight, I’ll say… Again, now, one or two? You can actually see that my instructions are getting smaller and smaller. Once I know that the patient understands the game, then I don’t have to keep explaining myself, and that saves you a little bit of time. Fan and block. What if I have this chart, but I have no JCC lens? And I love fan and block. I think fan and block is very, very helpful. You can see that you have a fan there, and you can see if you have a look at the picture there — you can see this little dial moving around. That dial with the triangle and the blocks moves around. So you’re gonna ask the patient: Which of the lines on the fan are clearest and darkest? Now, you can see the instructions are written out here. We’re gonna go through this relatively quickly. But I want you to have a look at the instructions. If you have any questions on this technique, if you don’t understand something, jump on Cybersight, on our discussion page, and I am happy to answer any questions that you have regarding this. So you’re gonna ask them which is clearer. They say 90 degrees. So if you move your arrow so it’s pointing perpendicular to that 90 degrees, so that arrow is going to be pointing to 180, and you know you’re pointing it at the right direction, because you direct the patient to the arrow now, and you say… I’m gonna move this around. I want you to tell me when the arrow has equally clear arms. And you’re gonna ask them which one of those… Sorry, which one of those blocks is clearer. The top set or the bottom set. If they say — and the aim of the game is to move — and you see the eye here? The aim of the game is to move both points of the astigmatism back onto the retina. And so you’re gonna add your minus cyl in the direction of the blocks that are clearer. You’re gonna continue to do that, until they say it’s equally clear. You can see here, when I started, I moved the circle of least confusion up, and I did that by just adding about half the astigmatism. There’s a neat little table down the bottom. If you’re not quite sure what their astigmatism is, and you’re a bit unsure about your retinoscopy, if you’re seeing about 20/40, for example, or 6/12, you’re probably looking at an astigmatism of about 1.50 or so. So that gives you an idea. So all of these are written out. What if I have no JCC lens, but I have this clock chart? Again, it works in a very similar way. You ask the patient — you put a +1 lens in front of the eye. And you ask the patient: So this is with no astigmatism lens or cylinder lens in there. And you ask the patient: Which line on the clock position is the darkest and the sharpest? Then if they say: Just say in this example — they say the 2:00 line is sharpest — so you can say okay. So you multiply to the position that they tell you by 30. And that gives you your degrees. So then you’re gonna place a -0.25 lens at 60 degrees in our example here, and you’re gonna ask them, again, which line is darkest and sharpest? If they say… Yeah, still that 2:00, you’re gonna now change that -0.25 diopter cyl lens to a -0.50. And now you’re gonna see… Okay, now which line is darkest and sharpest? And you keep adding that -0.25 lens in steps until the patient says they’re the same, or the lines look equal, or until they say a different set of lines look equal. So this is a nice way of finding out where astigmatism is. Can I use this to find astigmatism? Yes, you can. Stenopaeic slit is not used quite as often. But you pop it in the trial frame, and you get the patient to shift the slit around in the trial frame, until the vision is clearest. You want to make sure that you add a +50. You fog the eye a little bit before you do this. And then when the slit is aligned, you know that that’s where your minus cylinder axis is. And you can actually correct both of them. Both the minus and the positive cyl. Spherically, using this. So if you have any questions, please jump on our discussion board. Someone posted that they’re worried about vertex distance. Is that a concern? Absolutely. If you have a high prescription, you should be worried about vertex distance. So you want your lens in the back well to make sure that it’s closest to the eye. And you can see you’ve got a little ruler on the side there. You can actually measure what the patient’s vertex distance is. So when you’re prescribing their eyeglasses, you can match it. What about refracting over a pair of glasses? We’ve got these nifty little clips here called Bernell clips. These are just made by Bernell. They’re trial clips. They go over your glasses, and then you can do refraction as you usually would in a trial frame, but just popping the lenses in this well here. This is really handy for low vision patients or patients who have really high cyl or really high prescription. Or if you’re out and you don’t have a photometer or a lensometer to tell you what the glasses prescription is. And then when you get back to the clinic, where you have the prescription, you can work out what the prescription is, and prescribe it to the patient. What about low vision patients? And we had this question. What do we use? Do we use the -0.25 JCC or the -0.50? I would say you can use -0.25 or -0.50 in any patients that are young, that are 20/40, 2050. 20/50. Obviously if they’re young, that’s going to be fine. You want a bigger difference between the two flips, between the two sides. If a patient has lower vision, you’re going to choose the JCC lens based on how low the vision is. If the patient is 20/200, you want to make sure you have a just-noticeable difference of plus or minus 2. Plus or minus 1. So a difference of 2. So you want to say… Is it clearer here or here? And you want to make sure the difference between those two lenses that you’ve shown them is 2 diopters, because their vision is so low, they won’t be able to tell the difference if you give them options that are closer together. So a good little technique — if you’re seeing 20/200, that’s a just noticeable difference of 2. So you’re gonna use a plus or minus 1 JCC. So you can buy a plus or minus 1 JCC or plus or minus 0.75. Sometimes they come in, in a different set. Chart conditions. You want to make sure that your chart is clean. That it’s distinct. That it’s at eye level. Also in a screening situation, if you’re doing best visual acuity, if you’re testing for best visual acuity, that is absolutely fine, even if you’re mainly not exactly at 20 feet or 5 feet, whatever you decided the distance to be. As long as the chart doesn’t move. That’s okay. So sometimes in a screening position, we just have to live with the conditions that we have, and you put your chart up on the wall and measure from the wall. So as long as you don’t keep moving the chart or the patient’s chair, then you’ll be able to judge whether or not their vision is improving. LogMAR chart is a friend for all. Particularly as an Australian optometrist, I’m a huge lover of the LogMAR chart. There were two Australian doctors who came up with the LogMAR system. So you can move it to 6 meters or 20 feet, if you have that distance. Or 10 feet or 3 meters — you should expect it to get half as good. So you can calculate what the exact visual acuity is, even if it’s above or beyond what you can show them with your chart. So you can move around. You can adjust it for a screening situation. LogMAR charts come in letters, they come in tumbling Es, where the patient points which way the elephant’s legs are pointing or the legs of the E are pointing. LEA symbols are fantastic for children. They’re by far the best visual acuity chart and symbols you can use for children. They’re very well researched. And you can… Oh, sorry, that one went missing. Okay. We’re nearly there. What if I’m not sure if this patient will be comfortable with this change in refraction? That’s really handy with the trial frame. You can get them to walk around with it, and with their prescription. And what about finding a near prescription for presbyopes? So everyone reads at different reading distance, again, which is why it’s really handy for you to do your refraction in a trial frame. Because then when you give them their reading material, rather than it being set at 40 centimeters in your phoropter, they can hold it wherever they want to, which is fantastic. If you’re like my dad and he holds his paper out here, then you can prescribe for that distance, or if you’re like me, and you hold your paper… Or your book up really close, then you can prescribe for that distance. What prescription do I start with? And this isn’t really a lecture on prescribing. But those ages give you an idea of what kind of prescription you could start with. What you want to do is you start with that prescription, and then you want to say… Okay, I’m gonna show you some other lenses, and you’re gonna pop in your +0.25s from this set here, and say is it better with these lenses or better without? Whilst they’re looking at that reading prescription. I get a lot of things of… It’s awkward adding lenses over the top whilst they’re reading and trying not to block them. It is awkward, and I love my flippers for this reason. I have 0.25 plus and minus flippers, and so while they’re reading, I’ll say is it better with or better without? If they say better without, I’ll flip to the minus and say better with or better without? It’s just a little easier. So it’s a nice trick there. Lastly, with kids — what do we do with kids? You can get smaller trial frames with kids. And we had a question before. Can we do JCC with kids? No, you can’t, really. You want the kid to be able to tell the difference between your two views. But what I am gonna do is I’m gonna do retinoscopy. And that’s what I’m gonna mostly rely on. If I want to make sure that I haven’t overminused, because their accommodation is so active, but I haven’t cyclo’d them, I can do a fogging method, but essentially with both eyes. I’m gonna put in the +0.50 over both eyes, tell them it’s gonna be really fuzzy, and slowly decrease that until they can read the line that they were reading beforehand. So very similar to a fogging technique, but doing it binocularly. That’s the end of our lecture. I’m so sorry I went a little bit over. I’m just gonna check if we’ve got any questions here. Why negative cylinders only? Because I’m an optometrist, and that’s what optometrists work in. Sorry about that. How do you binocularly balance with prisms? We’re not gonna go through that. You can binocularly balance with prisms. We might actually cover that in the binocular vision lecture. But I’ll chat to Dr. Geiser about that. That technique will be in the manual that we post up online at the end of the week. Okay. I think that that probably answers all of the questions at the moment. Thank you so much for bearing with me. I’m sorry I went 15 minutes over, but I hope that was really helpful. If you have any questions about any of the techniques, particularly once we post the manual up online, please contact us through Cybersight. You go up on that discussion page, and ask any questions. We’d love to hear from you, and we’d love to hear from as many people as possible, and share as many patient cases as possible. So please join us online.
May 9, 2018