Retinoscopy is a well established and proven clinical technique performed as an objective determination for a patient's distance refractive error. The technique can be utilized as a stand alone determination of a patient's distance prescription or performed as a starting point to subjective refraction.

During this live webinar, fundamentals of retinoscopy are discussed. Basic optical principles, clinical procedure, clinical interpretation of findings and application of the technique through several case examples are also covered.

Lecturer: Daniel A. Bastian, OD, FAAO

Transcript

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Testing DR BASTIAN: Hello, everybody! And welcome to a webinar here by Orbis and the New England College of Optometry on retinoscopy. I hope everybody can hear me okay. And I look forward to, over the next hour, discussing with you this excellent topic of retinoscopy. My name is Daniel Bastian. I'm an optometrist here in the United States, specifically in Massachusetts, and I'm an assistant professor of optometry at the New England College of Optometry. I teach a first-year course on methods of optometry to students here in Massachusetts. I'm very excited to go over the topic of retinoscopy with you all. I see we have about 66 people listening in, so that's excellent. We only have about an hour's time here, and I know many of you have some excellent questions and some really good case-specific questions. I saw some of those on the registration/pre-registration. If you have more specific case-based questions that we may not have time for today, I highly encourage you to submit those questions to Cybersight.org. And then we'll have a little bit more time to address those questions. Hopefully I can get into some other things today. There's a large landscape of backgrounds as it relates to the topic and understanding of retinoscopy. This lecture is going to provide a solid foundation on this clinical technique, addressing some of the theory and some of the methods. And many of you may be a little bit more advanced, and have more specific questions about how to get to the next level, which I highly encourage you to submit. But I am looking to provide a nice solid foundation for everybody going through this lecture. So before I begin, I would like to say some special thank yous, first to my wife, Monica Nguyen. She helped with this lecture. She's also given a retinoscopy lecture at her hospital, where she works, and is a big inspiration. My mentor, who taught me about retinoscopy, Dr. Nancy Carlson, and my colleague and strong support, Dr. Fuensanta Vera-Diaz, who worked closely with me to help put this lecture together. I also want to thank Sara and Laura for helping to put this presentation together. So thank you so much. Now let's go ahead and get started. I wanted to get a sense of how everybody felt with their comfort level in terms of retinoscopy. So here we have a poll question. How comfortable are you with retinoscopy? The theory and the method? I want to get a sense of the audience. Do you feel fairly comfortable, not comfortable at all, or yeah, you're feeling quite comfortable, and you're looking to get a nice refresher? All right. About 42% of you said you're fairly comfortable. That's about half the group. Almost a third said very comfortable and a third said not to comfortable. Not so comfortable. And so are we working in minus cyl or plus cyl when providing clinical care? A lot of the cases are plus cyl, but they can easily be plus cyl as well. We're talking simple conversions here. But I want to get a sense as to where people are at. And minus cyl is 85%. In which case we're gonna go to a specific website to do some cases here. So in the next hour we'll talk about what retinoscopy is, be on the same page in terms of understanding and its definition. Once we understand what it's used for, we need to understand it in terms of optics and how it relates to the patient's optics and their far point. So that's really important to understand. If we can wrap our heads around the optics of our instruments we can better understand assessing the reflex, both against motion, with motion, and neutrality. This is what we as clinicians are gonna be seeing, so we need to know how to interpret those and get to our endpoint, which will be neutrality. I'll go over some tips and tricks, how to be careful of common techniques and errors that are made. Some examples I have. I have several -- up to seven. In the interests of time, we don't need to go through all of those, but I think it's important to go through some case examples and go through them. I'll also pull up a website that you can practice on yourself. We'll also go through some retinoscopy problems. That's kind of a sense of what the lecture is gonna be like. Here in this picture, you can kind of see that this technique can be performed on a large range of people, of age groups. Sometimes it's with loose lenses, as we see in this picture, in an environment where we're trying to assess objectively what this child's refractive error may be. But it can be done in the examination chair, with a phoropter, loose lenses, lens holders, lens racks as well. So what is this concept of retinoscopy that we're looking to talk about today? It's first and foremost -- needs to be understood as an objective determination of the patient's refractive state, by locating the far point of the patient's eye, with the retinoscope, and then using lenses to move the far point to the examiner's entrance pupil. The first sentence is underlined here, because it's important to understand it's an objective determination. In this lecture, we're not gonna be getting into subjective refraction. That's when the patient's responses are brought in, and we're refining on objective measurements a starting point for refraction. Retinoscopy is an incredible technique, because it allows us to objectively measure a person's refractive error. And being able to objectively measure it allows us to provide possibly clear and comfortable vision to a large population of people, many of whom I'm sure you're serving, who wouldn't necessarily be able to respond to us or maybe can't, for whatever reason. And so it can lead to final prescriptions, it can lead to starting points for subjective refraction, but it is an objective determination for patients not subjectively providing any feedback. So how does a retinoscopy work? Well, the retinoscopy illuminates the inside of the patient's eye. The clinician examines the light, as it's reflected from the external limiting membrane of the patient's retina. An objective measurement of the prescription the patient needs for distance, based solely on the optics of the patient's eye is what we're doing, and it's usually used as a starting point for subjective refraction, as I just mentioned in the previous slide here. But the main key point is the clinician examines the light as it's reflected from the external limiting membrane, and how we perceive that light is how we're gonna determine the refractive error of this eye. There is static, and there is dynamic retinoscopy. In the majority sense, we're talking about static retinoscopy as we go through this lecture. That's where a patient fixates at a distance target with their accommodation relaxed. It's very important. We want to try to eliminate the variable of accommodation, because it can change. It can move in and out. And we want to keep it constant, in order to better get a sense of their refractive error. That's static retinoscopy. A patient fixates on a distance target with accommodation relaxed, and the distance Rx is determined. And I'm gonna go over some tips and tricks on how you can help to get that accommodation to relax for your patient. But if their accommodation is not relaxing, then the results of the retinoscopy can be a little off. Dynamic retinoscopy, on the other hand, as contrasted to static, a patient fixates on a near target, and the status of his or her accommodation is evaluated. That's more of a near type retinoscopy. And some examples are MEM, Book, Bell's, Stress Point. And I know in a preregistration question, someone wanted clarification on what dynamic retinoscopy is. Hopefully this helps, in terms of the patients fixating at a near target, and the status of his or her accommodation is evaluated, as compared to static. So what are we doing here? When we have static retinoscopy, what are we doing? We shine the streak of light into the patient's eyes, and move it within the pupil, and we observe how the streak appears to move in the patient's pupil, which tells us where the far point of that eye may be located. Is that far point located between me and the patient? Is that far point located virtually or behind the patient? Is that far point located right at my entrance pupil? Where is that far point for that patient? And based on that is how I'm gonna determine their prescription. I'm gonna use lenses to move the far point to my eye, as the clinician, and then I'm gonna calculate the prescription the patient may need, once I've gotten the far point of the patient to my entrance pupil, and go from there. And we'll talk all about what it is we're doing here, as we go through. What are the optics of the retinoscope? This is an important concept to go over. There's two things to understand about the retinoscope. The first is that there's a projection system, and the other one that there's an observation system. And that's pretty much the concepts that go into a retinoscope. The projection system is to illuminate the retina. So it consists of a light source, typically a lightbulb, a condensing lens, which can be moved, a mirror to bounce that light in a certain direction, a focusing sleeve, and then some type of source or current, in order to provide energy for the instrument. And so that whole thing together is known as the projection system. Then there's the observation system, which most simply is: For the examiner to see the retinal reflex from the patient. So that's what we're working with. And here's kind of a diagram that's maybe cut a retinoscope in half, so you can see within it. Here's the light source, the lightbulb. Here's the condensing lens, the mirror the light is bouncing off of, and this is heading towards the direction of the patient. The patient would be over here. The observer, the clinician, would be over here on the side. So here we have a question. I'm interested in what the audience thinks. You've done very well so far. Which is more accurate? Is it the concave mirror or the plane mirror? Is it the sleeve up or the sleeve down? Which do you think is more accurate, in terms of determining? Or quite simply are they equal? I'll give you a little more time to answer this question. Interesting. Plane mirror is more accurate. 54% of you said plane mirror. Really the answer is that they're equal. In the sense that one technique -- whether it's sleeve up or sleeve down -- it's just a different way of performing retinoscopy. Certainly, plane mirror, as 54% of people responded, is more common. It's how I perform retinoscopy the majority of the time. But I have opportunities to go into a concave mirror, a sleeve up situation, in order to check certain things or to assist me. A lot of people like concave mirrors, especially with high myopes. We'll talk about that a little bit later. Or myopia in general. So the reality that I wanted to illustrate is that they are equal in their technique. It's what you feel more comfortable with. It's not necessarily about accuracy. It's about what you feel more comfortable with, what you find is easier to perform this skill. And certainly that tends to be plane mirror for most people, just based on their training. So what are we talking about? Concave mirror is when you have sleeve up. Therefore the light coming out of the retinoscope is converging. And the motion that you're gonna see is gonna be opposite than maybe what you're used to with the plane mirror. With plane mirror and sleeve down, the light coming out of the retinoscope is diverging. If you see with motion or you see against motion. It's opposite when you do concave mirror with sleeve up. But the reality is that neutrality is neutrality, regardless of whether it's sleeve up or sleeve down. So they're equal in terms of accuracy, although one technique might be slightly more comfortable for you. And there are advantages to when you might want to have sleeve up or sleeve down. The reality is, based on experience and mentors and using this instrument, you're often going between the two, you're often feeling comfortable and checking yourself, because again, neutrality is neutrality. So in order to get through retinoscopy, it's important to conceptualize a patient's far point and how that relates to their refractive error. So what is the far point? It's the point in space that's conjugate to the fovea, when accommodation is relaxed. A point in space that's conjugate to the fovea, when accommodation is relaxed. For myopes, the far point is gonna be between the clinician and the patient. So that far point rests between the clinician and the patient. For hyperopes, however, the far point is located behind the patient. When you have cyl and you have astigmatism, so the power -- principal meridian behind the cornea are more than 1, it's not the same power all the way around, you have two far points. One for each of the principal meridians. Emmetropes have a far point at infinity. So when we know a myope's far point is between us and the clinician, that means we can put ourselves at the far point if we wanted to. You couldn't for a hyperope, based on where it is. And you're gonna be using lenses to manipulate these far points to put them at you as a clinician. Here's a very simple schematic that goes over refractive error as a nearsighted individual looks at infinity. Therefore parallel light. The light converges in front of the retina. And for a hyperopic eye, the light converges here. So... Let's get into how do we properly assess that reflex. This is really important in terms of us understanding this concept of retinoscopy and what we're seeing -- what does it mean and how am I gonna handle it as a clinician? So there are different characteristics of that reflex, when you're looking at it. The reflex can change its speed. It can be really fast. It can be wider or thinner. It can be brighter or duller. And those characteristics of that reflex are important for you to understand, because they can relate to the magnitude of the refractive error, and the type of the refractive error, and where you are relative to finding neutrality. Okay? So for a large refractive error, related to the width of the reflex, it tends to be more narrow. And I will illustrate that in some examples coming ahead. When the width in a small refractive error -- it tends to be wider. Okay? So as you're assessing your reflex, it helps to teach you a little bit about what to expect with your patients. The brilliance or brightness of it... When you have a large refractive error, it tends to be more dull. And I'll take a moment to repeat this several times throughout this webinar. When you get a patient who -- you have never determined their refractive error before, and it ends up being very large and the reflex is dull, you might think you're already at neutrality when you start performing retinoscopy. And you should learn some tools and tricks in order to check yourself. To make sure that you are truly at neutrality, both being comfortable with what neutrality looks like -- because these large refractive errors have been known to trick people. They're so large and the reflex is so dull, you might actually think you're at neutrality. And so the brightness is gonna vary based on the reflex and refractive error. When a patient has a small refractive error, it tends to be bright reflex. The speed of your reflex can change. Large refractive errors -- tends to be more slow. Smaller refractive errors, your reflex might move a little quicker. And this can help you as you're going through the scale, and getting closer to your endpoint, as you start to see the reflex get faster and faster. The direction of the reflex is very important. For hyperopes, you're gonna see with motion, generally speaking. And for myopes, you're gonna see against motion, generally speaking. Okay? And depending on where your sleeve is, sleeve up or sleeve down is gonna relate to that type of motion. So as we move the streak within the patient's pupil, we observe how that streak appears to move. And this is your interpretation of the clinical findings. If the reflex -- and let me just use the mouse here to point to the reflex -- this is the reflex inside the patient's pupil. This is our streak of light. Which is outside the patient's pupil. And this streak of light is gonna be controlled by you as the clinician, and be moving in a certain direction. This reflex inside the pupil is gonna move in a certain direction, based on the refractive error of that particular patient. And based on where the far point is for that particular patient. So keeping in context, these examples are based off of sleeve down, a plane mirror-like retinoscope. When you have against motion, the reflex moves opposite, and the far point is between you and the patient. You are scoping from left to right in this particular example, and you notice that the reflex inside the pupil is moving from right to left, opposite or against the way that you were moving. And that would signify to you that the far point is between you and the patient. With motion is this concept that refers to the reflex moving in the same direction as the streak. And the far point is behind or virtual. So here the clinician controls the streak of light, moving from left to right. And the reflex seen within the pupil also moves from left to right. And that is what would be referred to as with motion. The reflex is moving in the same direction as you. Neutrality here, the reflex does not move. The pupil is filled with light for a moment in time, as you scope and move past it. Far point is at your entrance pupil. You have to keep in mind you as the clinician -- and those who will have done this before will know this -- you want to be going back and forth, back and forth, in order to assess the reflex, get a sense of it, moving it back and forth, back and forth. And if I go back and forth, back and forth, and I see the reflex like a beacon of light coming out at me, that would indicate neutrality. If I see the beacon of light moving with me, that would be with motion. Or if I see the reflex moving opposite, that's against motion. So here's an example. A quick video. Hopefully we can watch this together here. Hopefully everybody can see this. Of what against motion is gonna look like to you. And maybe all of you are very familiar with this. But as they scope to the right, the reflex moves left. As they scope to the left, the reflex moves right. Let's just pause here for a second. This is the reflex in here, in this video. And the scope of light is going on the outside of that. Let's kind of start over for a second. So in that example, the light just went from right side to the left side. And you saw the pupil reflex move in the opposite direction. So this represents the reflex. This represents the direction of the scope. And you can see that they're going in opposite directions, which would be against motion. All right. That's a really good example of against motion there. Here I want to show you a couple more examples of what against motion might look like, when you're dealing with a low myope, versus when you're dealing with a high myope. Let's watch them individually here for a second. So when you have a low myope patient, you can see that it tends to be bright reflex, wide, and pretty fast. And what I mean by wide is edge to edge of that reflex is pretty wide. And this would indicate the characteristics of a reflex for a low myope. All right? And if we come over here, and we look at a high myope, the character of the reflex changes. It tends to be more dim. It tends to be narrow and slow. And what I mean by narrow is actually the very center of that reflex. You can see that the majority of the light is pretty diffuse, kind of spread out. That's not the width of it. The width of it is just that center beam, and in the first example it was quite a bit larger. In this particular example, it's much more narrow. I was a little confused about that. It's not the entire light. It's just the center of it is very narrow. And this is an indication of somebody who would be a high myope. Okay. Let's take a look at what it's gonna be like when we have with motion now. Okay. And again, for clarification, this is the reflex. Okay? And the scope of light that the clinician is using is outside of that. And we are watching this reflex here. And as the scope of light moves to the right, so did the reflex. To the left, so did the reflex. To the right and to the left, we see that the reflex is moving in the same direction as us. And therefore we have with motion here. Again, a couple of examples here, of what with motion might look like, when you have a low hyperope, versus when you have a high hyperope. For low hyperopes, the reflex is gonna have characteristics that are brighter, wide, and fast. Versus a high hyperope, where it's dim, narrow, and slow. Just like we saw for against motion. That's one meridian. Scoping the 180. This is scoping the 90-degree meridian. Let's take a look at the high hyperope. Much more dim, narrow, and slow, when you have a high hyperope. Here we're scoping the 9-degree meridian. And hopefully this illustrates -- you might feel like you're actually at neutrality in some instances. Maybe it looks like it's not moving at all, and just blinking towards you in that example. But it's not. That's an example of a high refractive error. And what does neutrality actually look like? It's always important to know where it is we want to go, what our endpoint should look like. So we're gonna take a moment here to watch a video about what neutrality looks like, so we can know we're there. Otherwise we might be performing retinoscopy for too long. So no matter what direction I move my streak, I just see this reflex kind of blinking at me. Not indicating whether it's moving with me, with motion, or against me, against motion. It just appears to fill up the entire pupil space. And blink right at me. And this is what we would identify as neutrality. I have another example here. Using this simulator, which I'm looking to show you, as we go through examples. This is a website simulator, that you can kind of work through, and we'll likely do that together. Putting in some lenses, I've now reached neutrality. And that's a nice bright reflex. And you're not seeing any type of motion with that. Okay? So once we as the clinician have determined using lenses that we've reached neutrality, we then need to take into consideration our working distance. So, like, how far away are we from our patients? How far away we are from our patients is gonna relate to the characteristics of the light that is coming out of our retinoscope. And so there are two distances that we work at, when performing retinoscopy. So the working distance is the lens needed for neutrality -- only gets the patient's far point to your entrance pupil. Once you put in your working distance, you're then able to move their far point to infinity, and that would be the refractive error. So to correct the patient's refractive error, you need to get the far point to infinity. By adding your working distance lenses. If you're working at 67 centimeters, it's -1.50. If you're working at 50 centimeters, it's -2.00. The final number is your net retinoscopy findings. Okay? So as you're performing retinoscopy, and you're assessing the against motion and assessing the with motion, and you're using lenses to then get it to neutrality, you need to then put your working distance in, in order to get the person's prescription and their final refractive error. Because the working distance is gonna put their far point at infinity, not at your entrance pupil, which is what you did for neutrality. Okay? And there are some suggestions, in terms of: How do I know that I'm sitting at 50 centimeters? How do I know I'm at 67? That's something that you as a clinician are responsible for, and you need to get comfortable with. That's where a lot of practice with this procedure comes into play. As I was learning this particular skill and as I teach students going through school, we tie stringing to our retinoscope at a particular distance. If you drift back and you're no longer reaching your patient at a particular distance, you have to know that you're drifting back, or that you're getting too close. There might be situations where we change our working distance in order to better assess the reflex. That's not what I'm talking about right now. But that's something that has to be pretty steady. Your working distance. Certain clinical situations will lead to us changing our working distance, but ultimately, we'll go back to these two. And you should go with whatever you're comfortable with, whether it's 67 or 50 centimeters. Test yourself, make sure you can always hold that distance, and that's gonna keep your retinoscopy findings very consistent. A lot of questions on preregistration were about how do I maintain my accuracy or how do I prescribe -- and it really starts with being able to hold your working distance accurately and consistently, as you go through practicing the skill. So there's this concept that you'll read about in the literature, about gross retinoscopy, and net retinoscopy. So gross retinoscopy is the lens that brings the patient's far point to the examiner's entrance pupil. That's occurring as you're performing your skill and getting yourself to neutrality. But that's not the final endpoint. You want to get yourself to net retinoscopy, which is the gross retinoscopy plus your working distance, minus 1.5 or minus 2. And the patient's final refractive error, that you've determined objectively, as either the starting point or something to prescribe, will be the net retinoscopy. So in going through some examples here, with the sleeve down and the working distance at 50 centimeters, you see with motion with +2 lenses, and you find neutrality. Okay? What would be the net retinoscopy -- the net retinoscopy here would be Plano. With the sleeve down and the working distance of 50 centimeters, you see with motion, with 2 diopters, you find neutrality. So your gross retinoscopy is +2 diopters. You need to then add in your working distance. Your working distance is -2. Therefore this particular individual is an emmetrope. I'll digress for just a second. As you start to advance in your skill of retinoscopy, you want to be able to tell what +2 might look like, even with no lenses. Get a sense of what that reflex will look like when somebody is +2 without any lenses. It's gonna be with motion, yes. But how fast is it? How bright is it? What do the characteristics of that reflex look like? So that way you can take individuals and maybe screen them in their different meridians, and be like... Yeah, that looks very close to what the +2 reflex would look like. And therefore you know that they have a low refractive error or might be emmetropic, and you can quickly identify that. So my piece of advice, or a tip or trick, would be: As you're practicing this particular skill, learn to identify what the characteristics of the reflex look like, and how it might relate to your working distance. Okay? With the sleeve down, and the working distance at 50 centimeters, you see with motion with +50 lenses, to get you to neutrality. So you had to use +.50 lenses to get you to neutrality, but you have to add in the -2 lenses, so therefore their net retinoscopy is -1.50. So even though you had to use plus lenses to get to your entrance pupil, the person is actually myopic and needs -1.50. With the sleeve down and working distance of 50 centimeters, you see with motion with a + 4.50 lens to find neutrality, and therefore this person's net retinoscopy is gonna be +2.50. Okay. Let's discuss this technique. So that we can work on enhancing it, and having a solid foundation for practicing this particular skill. When you're performing retinoscopy, you want to hold the retinoscope in your right hand and use your right eye to scope their right eye. The patient's right eye. Okay? This is important, that you perform this skill properly, where you're using your right eye and the retinoscope in your right hand, and you're scoping the patient's right eye. This places your left eye and the rest of your body outside the patient's field of vision. Okay? For this particular test, as we'll get into, the patient needs to look at a distant target. Why a distant target? They need to be able to relax their accommodation. We want to control accommodation during this skill. And so the patient should look at a distance target, because we know that helps to relax accommodation. If I am using my left eye and my left hand while I scope their right eye, I'm basically right in front of them. If I'm basically right in front of them, at only 50 centimeters or 67 centimeters, they're likely to be accommodating and looking right at me. And if they're accommodating, that's a variable I don't want in my technique, in my test, because it could throw off my results. So this is why it's helpful if you hold the retinoscope in your right hand, using your right eye. You ret their eye. Okay? That places your body outside their field of vision. They can use their left eye to look at the distance target, therefore controlling their accommodation. Not to mention you'll have a free hand to be able to use lenses. Whether they're loose lenses or in a phoropter or in a lens rack, you'll have that hand free. And you want to get yourself to a point, when performing this skill, where you're constantly moving lenses to find neutrality, and if you're no longer moving lenses, you're done. That should be your endpoint. You know that no matter what type of reflex, you know how to change it and get to neutrality. We often see a lot of people learning the skill for the first time that they really spend a lot of time focusing in on that reflex one click at a time, one lens at a time, and only moving their lens rack one lens at a time. You don't necessarily want to did that you don't necessarily want to do that as you advance through this skill. As you advance through this skill, you want to move those lenses quickly to get here. You don't want to be scoping them for too long. Because you're gonna affect their accommodation, you're gonna affect your accommodation, and that can change the results. So try to work quickly. You want to scope all meridians of the person's eye, in order to pick up astigmatism. Again, a lot of the questions that came in on preregistration were about how to determine prescription or how to detect whether the person has some cyl. But one of the ways you want to start is by scoping all the meridians. If the reflex looks different, faster, wider, brighter in one meridian, as compared to another meridian, where it's more dim, slower, and more narrow, that's an indication that the patient has different powers in those meridians, and if they have different powers, they're definitely gonna have astigmatism. So you want to scope all the way around, finding the principal meridians, and then neutralizing those. You want to neutralize the meridian with the most plus, least minus first. This is especially true if you're using a minus cyl. For the audience members who use plus cyl, you want to use the most minus, least plus first. But for our case, with minus cyl, you want to do least plus, most minus first. Look at perpendicular meridians. When you're scoping and you find neutrality and you go 90 degrees away -- we're gonna assume they have regular astigmatism -- and you see it still looks neutrality, those meridians are of equal power. If they're not, if you still see some motion, then you know you have powers in these different meridians and you have astigmatism. Meridian 2 really should show against motion, if you're working in minus cyl. So when I neutralize one meridian, say I see with motion, I see with motion, I see with motion. I know I neutralize with motion, with plus. Now I've gone to where it's reversed, I find neutrality. I go to my second meridian, and I now see with motion again. If I have minus lenses, I can only neutralize against motion. Remember that. If I only have minus lenses, I can only neutralize against motion. If I have with motion when I go to my second principal meridian, I don't have any lenses to neutralize that in a phoropter with minus cyl. That's fine. You simply chose the wrong meridian first. So you have this meridian, neutralize that, and when you go back to the first meridian, you'll see it's against motion. You don't have to be too hung up on it. This is something we see in people who are learning this skill for the very first time. They get very stressed out or anxious about making sure they find that first meridian that's most plus. Or least minus. You don't need to worry about that. Pick a meridian find neutrality. If you go to your second principal meridian, if you don't see what you want, you just have to reverse your axis by 90 degrees. You just chose the wrong principal meridian first, and you should be able to quickly adjust to that. If that doesn't make any sense, I'm more than happy to clarify that. But I think it's an important clinical concept of being able to develop this skill faster. You know you have so many different demands in terms of getting through the examination, see as many patients as you possibly can, and provide enough help for everybody. And one of the ways of getting faster is not agonizing over which is the least plus or minus meridian just pick one. Find neutrality. When you go to the second one, if it's not the right one, just adjust yourself. I think you'll be able to go through a lot of faster. And when you find neutrality in both principal meridians, you'll add in your working distance. One comment to add is some people were asking about: How do I keep track of my meridians? And don't mess it up? If you're working with loose lenses or with a lens rack, you are gonna need to put these in optical crosses. And the more you practice the more able you'll be able to do that inside your head. Just remember you're neutralizing one meridian at a time. And put it on an optical cross. And then it'll go into what prescription you write, minus cyl or plus cyl. Let's go streaking! Retinoscopy motion depends on the patient's refractive error, the status of accommodation, lenses placed in front of the patient's eye, and your working distance. In terms of status of accommodation, there are several different techniques used to control accommodation. A lot of people like to fog the left eye when they start performing retinoscopy on the right eye. I highly recommend this. Only a diopter to a diopter and a half. That person could easily be +2 or +1.50 and you don't know. So you have to go to the left eye and look at the type of reflex and actually throw in some lenses in order to get it to about a blur of a diopter to a diopter and a half in order to control their accommodation. That's also true -- if they're a really high myope, you might want to give them some minus to lower that, so they don't go tonic accommodation on you. Another way is to put up a red-green distance target. And a big E. There was a question in the preregistration about duochrome and how to perform that test. Unfortunately I'm not doing subjective refraction in this particular webinar. This is focused on the fundamentals of objective retinoscopy. So the duochrome test would be for a different webinar. Here we have moving the streak vertically, horizontally, and obliquely. You need to be comfortable with rotating your streak. This is where spot versus streak comes in, in terms of retinoscopes. I've only ever used a streak retinoscope. I've never used a spot. A spot certainly has helped a lot of people and is a very good technique. But the streak is a little bit easier in terms of determining that refractive error, specifically as it relates to astigmatism, and getting the axis down correctly. So a lot more people are using streak retinoscopy, and I think that's important. So appearance of the retinoscopy reflex. When you're far from neutrality, it's gonna be dull and it's gonna be slow. When further from neutrality, even greater than 6 diopters, it almost appears as if there's no reflex. I'm gonna show you a simulated example of that, example 7. It almost looks like there's no reflex altogether, and you might even think you're at neutrality because of that. You need to be careful. Large refractive errors can easily trip people up into thinking they're at neutrality. What you should do is throw in a lot of lenses. This is one technique. Throw in a lot of lenses. Either direction. Just to see if you can start seeing some type of reflex and some type of motion of that reflex. And once you get motion of that reflex, you'll know what direction to go in. Either continue in the direction of the lenses that you placed or in the opposite direction. Sometimes people like to get a lot closer. And we'll talk about radical retinoscopy, where you get 12 centimeters away and change your working distance in order to see what type of reflex. That works well for high refractive errors, and you can actually back yourself up, back to your normal working distance once you've gotten the reflex and you've been putting in some lenses. Between 1 diopter to about 3.5 diopters from neutrality, you usually see a line. And as you get closer to neutrality, less than a diopter, the reflex is wide, almost begins to fill the pupil, even closer to neutrality, the reflex moves very fast and is very bright. I highly recommend, when you're performing retinoscopy, another way to get faster and more accurate with this technique is bracketing. So when you see a particular type of motion, say it's with motion, you just keep adding in plus until that reflex goes against motion. And then you go back. Now it's a bookend. You know you don't need to go past that. You've gotten to it quickly. And now you can spend a couple of seconds, half a minute, to refine that, and really pay attention, to get it to a very accurate spot. But I wouldn't waste time until I've gotten my reflex to reverse. Okay? And that can be helpful. What orientation should your streak be at? This is an important question to ask yourself. How do I know if my patient has astigmatism? Well, there's gonna be characteristics to the reflex that you see that are gonna lend itself to understanding whether a person has astigmatism. The thickness and brightness of the reflex, as you rotate it. We already mentioned that. Pay attention to all the different meridians. As you rotate your reflex, you want to pay attention to the characteristics of that reflex. If you see a break, what does that break mean? If you look at this example here, you see that maybe you're scoping at 95 or 100 here. That's the orientation of your streak. You're actually scoping the meridian that's 90 degrees away from that. But the reflex inside the pupil has broken away from where the alignment of your streak is. They really should be together. They should be lined up together. Not lined up here in this example. Lined up here in this example. And that's what you want. That's how you know you're scoping the right meridian. That's how you know you're at the axis. So pay attention closely to whether or not there's a break in the reflex. After you neutralize one meridian, you rotate the streak and find the meridian that is not neutralized. And that's important. Here's an example case on this simulator program, that is a website, that you may be able to have access to. So in this particular example, first step, scope both meridians. So here we're scoping the 180-degree meridian. Now we're rotating our reflex and scoping the 90-degree meridian. Pick the meridian with most minus, least plus, if you're working in plus cyl form, or most plus, least minus, if you're working in minus cyl form. These are interchangeable. And then neutralize perpendicular meridian, and you're gonna add in your working distance. We have against motion still. We're gonna add in some minus lenses. That looks pretty close to neutrality. Go up a little bit more. The motion is reversed. We see with motion. We know we need to go back down. Yes, that looks pretty good, in terms of neutrality right there. Let's rotate our streak. Turns out the other principal meridian looks to be at neutral right now. So I think we're at neutrality, and this is a spherical eye. I'll click this button and see refraction of -7. -5 with -2 working distance is gonna get us to -7. Okay? Let's go through another example. You want against, scope both meridians. Pick most plus least minus. Neutralize the motion. Here we have with motion. Still have with motion. Increase more plus. With motion. Reflex is starting to change a little bit here. All the way up to about 5.50. Our reflex has gotten faster. It's gotten brighter. That looks pretty close to neutrality right there. Maybe go a little bit more. Let's see if this reverses. It does. We now have against motion. Back it down a little bit. Looks like neutrality. What's our next thing? We've got to reverse and check all principal meridians. Sure enough, looks pretty neutral right there. So +6 with a working distance of -2 would give us +4 of a spherical eye there. So those are just some simulated examples of how you kind of want to work on your technique here, as you go through it. We have some more examples. I have case 3, case 4, case 5, case 6, and case 7. In the interests of time, because we only have an hour of lecture, I want to show you where you can go to actually work on some simulated examples of this case. So we're gonna leave the PowerPoint presentation for a very quick second. I'm gonna bring up a website that you can use. Because we just don't have time to necessarily go through each of these individual cases. And they're kind of the same. What I would like to enable you to do is be able to go to a went is be able to go to a website that can allow you to practice and create any case that you want. So I'm gonna exit this PowerPoint presentation, and then come over to this website here. So this website is... Whoops. Hopefully you can still see me. >> Yep, we can see you. DR BASTIAN: Okay, great. So this website is http://eyedocs.co.uk/ophthalmology, and you can find this retinoscopy simulator. And you can determine what patient you want. Do you want myope, hyperope, myopic astigmatism, compound myopic astigmatism, hyperopic astigmatism. You can work in plus or minus cyl, you can hide the answers so you don't have to see it, and what you simply do is work on this type of reflex. So here I have with motion, right there. And my orientation streak is vertical. Therefore I'm scoping the 180 meridian. If you change this, and you can just play around with this, I'm able to scope the different meridian. I'm able to scope the 90-degree meridian. And what you simply do is you put lenses in. And you assess that reflex. I've still got with there. Still got with there. Increasing the magnitude. My reflex is getting better. Et cetera. Now I have against. I might back it off. I'll make this website link also available, so that everybody can kind of get to it. But I think this is a great technique to practice your skills a little bit. And that looks like it's neutral there. Rather than walking you through specific examples, this will enable you to create all your own examples. I do think it's helpful to take a look at this example I put together, called example 7. Okay? Let's take a look at example 7 that I put together. And what you'll see here is an example of what can happen when the reflex appears to be nonexistent or super dull. So we just scoped the 180-degree meridian. We didn't see much. We're now scoping 90. We don't see much. So what should we do? I highly encourage you to be able to just throw in lenses and then be able to assess any type of motion that comes up. Because now we're starting to see some type of dull reflex. And the reason it looked so difficult at first is because this refractive error is probably a pretty large magnitude. Now I can actually see some break. I think this is a good example of a break. If I go back just a touch, see how the reflex is not in line with my streak? When the reflex is not in line with my streak, that's a break, and that's an indication that there might be some astigmatism there, and you're gonna need to orient your streak differently. Here we are, changing the streak, the orientation of the streak, and now we've got better alignment there. And now we're able to assess this reflex a lot better. It's more comfortable to what we normally are at. Okay? I've got some more slides that I want to go over. But that was just to illustrate to you, when you have very large refractive errors, you might just need to throw in some lenses and begin figuring out what's going on. Many of you are very interested, I know, in how to deal with more complicated situations. What do I do if there's an opacity? What do I do if there's corneal edema? How do I still perform this skill? Those are really excellent questions, and what you can do is kind of alternate your working distance, you can kind of come off-axis a little bit. I want to get into some tips and tricks, as we go through here. So problems with retting. You might have poor reflex, high refractive error, opacities, or scissoring. I know that's an important concept. Scissoring. What does that mean? That means as you are scoping, the reflex appears to split into two. It appears to scissor itself. And that can be very confusing. Is it against motion? Is it with motion? What am I seeing here? It can be very difficult. So this is kind of an example of what you might see when you go through scissoring, where it kind of breaks off. My biggest piece of advice for you is to stay in center of the pupil, and keep your strokes maybe smaller. Don't go and make these large strokes with your retinoscopy, and don't look towards the edges of the pupil. If you stay towards the center of the pupil, you make smaller strokes, you'll be able to better assess and not be so bothered by scissoring. Scissoring is a clinical indication that maybe there's quite a bit of astigmatism, or maybe this person has keratoconus. So if I see scissoring when I'm performing retinoscopy, I do my best to get to my endpoint, to get to neutrality, but I also keep in mind... I have to look at the K values, look at if I'm able to get this person to 20/20, because they may have keratoconus that's been undiagnosed, and I can pick it up through retinoscopy. So here are some tips. Retinoscopy. If you are not getting a red reflex, consider reducing the working dance only momentarily. That's where the radical retinoscopy might come in. Or doing an off-axis retinoscopy. You don't typically want to do off-axis. You want to stay down the visual axis. But if you need to, you can go off-axis to look around at opacity. Bracketing lenses can be very helpful to get to where you want. Retting over existing glasses can give you an idea. Knowing what +2 looks like with your streak, knowing your reflexes, because you know that if I just put in my working distance, the reflex is gonna go away. I'm familiar with the characteristics of that reflex. Check if you overminused by adding plus lenses and repeating it. When you put your retinoscopy in and you're able to ask them what they can see, sometimes they see 20/20, but you might have overminused them. Add a little plus into that to see if it reduces their vision, as it should, indicating that they're not overminused. If the vision stays exactly the same, that's an indication that you did overminus them. Because they didn't need that strong of a prescription. If you're getting into the habit of overminusing people consistently, it could be because of your working distance. You need to check that. You might be putting in -2 lenses but you're only working at -.50. If you have small changes in the pupil, you want to suspect latent hyperopia. If the pupil is changing in size, it's getting a little bit bigger, a little bit smaller, it's moving on you, that could relate to some accommodation or to the fact that they might be hyperopic. If you get a large pupil, they're dilated, or you're performing a cycloplegic retinoscopy, which I encourage you to do at times, you want to stay towards the center of the pupil. You're gonna get more aberrations as you go away from the center. What are the most common errors? People perform the technique off-axis. They tend to be tilted, don't look down the barrel. I said you have to do that in some more difficult situations, but in working on your technique, stay on-axis. They choose the wrong target, not far enough or too small. They block the patient's view. This happens all the time. If you can communicate with your patient effectively, that's great. If you can't, though, you need to be aware of whether or not you're blocking them. The patient looks at the retinoscope light and not the target, or you take too long, so their accommodation changes, and your accommodation might change too. A lot of people learning the skill creep too close or too far away. You can check the working dance, and I encourage you to do that. Not accurately to determine the presence of astigmatism, inaccurately determine the orientation of the main meridians, confuse the axis of the corrective cyl, or hold the lens rack too far away or loose lenses too far away. You want to get the lens as close as possible, so you're not changing the effective power of the lens. Hold the rack from the lens rather than the handle. That can dirty your lens. Incorrectly subtract or do not subtract the working distance to obtain the net retinoscopy, and then report the gross ret, when the preceptor asks for your results. You always want to keep track of what is your net retinoscopy, what is your gross retinoscopy, and put that in exactly. The focus of the lecture was to provide a solid foundation for people. I understand everybody's background and competencies are probably different with retinoscopy. I'm gonna open up the question and answer box, with an opportunity to address more specific questions, as we have about five minutes remaining in this hour. Again, I highly encourage you to submit any questions to Cybersight. Specifically if you have a clinical question that might require some detail to get into. But I do hope that you get a chance to do that. And hopefully this provided some foundation here. So I'm opening the question and answer box. Let's see what we have open here. Let's see here. Thank you for changing that. Difference between pupil fill and cross... Some of these are just a little bit difficult to interpret. So I'm just trying to read through them and figure out one that I can interpret properly. Okay. That's a good question. How can I know the most plus, least minus, in the beginning? Most plus, least minus is what you're gonna want to do for somebody who you're working in minus cyl, and I think that's a really important question. You're not yet familiar with the reflexes and their characteristics. And so in the beginning, I would highly just suggest: Pick a meridian. And work on your skills of being able to achieve neutrality. Once you get neutrality and you reverse it, if it's not the motion that you want, so if you're working in minus cyl and you're going to your second principal meridian and you see with motion, you just chose the wrong meridian from the beginning. And then just neutralize that meridian now, and when you reverse it, you'll see against motion. For those who are starting off, and you're like -- how am I gonna know? Which is the most plus, least minus? Choose a meridian. Achieve neutrality. If you don't get what you want, you just chose wrong. The questions are coming in. These are great questions. You guys have been an awesome audience. Some of them are coming in fast here. The working distance -- is it a minus sign, or you just subtract the working distance? That's a good question here. You're gonna add a negative number. The light coming out of the retinoscope is affecting -- is divergent. Therefore there's power from the retinoscope. So when you want to put your working distance, therefore backing the patient's refractive error up to infinity, you're gonna add in a negative number. Okay? You're gonna add in a negative number. To the phoropter or to your optical cross, or whatever it might be. You're gonna add in a negative number. Okay? That was a good question. What are my preferred targets at 6 meters? That's a good question. So I typically just use a large E, and I'll put a red-green filter in. That's just been my training. But sometimes a patient may not be able to even see that at all. So any type of target that they can somewhat look at, and pay attention to. You know, for a lot of kids, I work to just try to get a video going, or some type of animation. Or characteristics. Because I want to keep them distracted. You want to keep them looking at a distance target. That can be really helpful. One of the questions I did want to address in these last couple minutes, that came up in the preregistration, is: You know, with autorefraction coming out these days, why do we need retinoscopy anymore? If I can get autorefraction with a click of a button, retinoscopy doesn't seem to be too significant. And I want to stress the importance of retinoscopy. It's a very important skill, because it's dynamic. You're able to look at the reflex, at the refractive system, as you're doing it. You might be able to pick up opacities better and have a sense of the refractive error. You don't get that through automation. Not everybody is able to sit and be in an automated autorefractor. For many situations I find myself in, wheelchair or bedridden or whatnot, it's an important skill to have. I work closely with a pediatric ophthalmologist, well known, chief of a major city hospital here, and when you ask him what is the most important skill, he will always tell you retinoscopy. And that's coming from somebody who has done this for quite a long time. It takes a lot of skill, a lot of practice. I know you guys can do it. Hopefully this provided some foundations for you to work through and keep track of. Really it's a motor skill and getting out there and doing it as much as possible. I hope you guys enjoyed this. I look forward to maybe answering some more questions and working with Orbis and Cybersight to help address some of these questions. But I hope you all have a good rest of your day. >> Thank you, Dr. Bastian. DR BASTIAN: Thank you.

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Question: Could you please short explain about Hypermetropia skiascopy? How give child glass prescription?

Answer: First I start without the skiascopy lenses (these are commonly referred to as "retinoscopy racks" in the USA) and without the skiascopy racks I first I assess the movement of the reflex and if there is any astigmatism. If the child is hyperopic, as you have suggested in your question, I would expect to see a "with" reflex movement with my retinoscope sleeve down. I then place the black skiascopy rack of lenses in front on the eye, with the eye looking through the +2.00D lens (I work at 50cm working distance so this is the equivalent to net refraction of plano) and I see how the reflex motion changes. Make sure when you place the skiascopy racks in front of the eye that you are not blocking the other focusing eye with theskiascopy rack or your hand. If the child is hyperopia I should expect to see a "with" reflex and I would continue to move up in power until I saw a neutral reflex. If there was astigmatism present, I neutralise one meridian, remember the power and axis, and then find the other meridian perpendicular to the first and neutralise it. I remember both powers at both axes, then write out the prescription with the help of a cross cylinder picture - have a look at the retinoscopy handbook online for an example of this.

Question: Please explain hypermetropic retinoscopy and with +glass prescription?

Answer: When you see with motion it should be neutralized with plus lenses.  Once the working distance is taken out, if the prescription remaining is still plus then it is hyperopic.  In regards to prescribing it depends on the symptoms of the patient, best corrected vision and if the prescription is potentially amblyogenic.  I always push as much plus needed to remove any misalignment.  If patient has eso and the plus helps with the eso you have to push as much of the plus, from wet retinoscopy to make the eye straight.  you always want to prescribe the maximum amount of anisometropia that is found on either dry or wet retinoscopy.

Question: Difference between pupil fill and cross reflex?lease explain hypermetropic retinoscopy and with +glass prescription?

Answer: This takes practice. The closer you get to neutral the thicker and faster the reflex motion will become. If you're having trouble identifying neutral, try slowing down your retinoscope movement across the pupil. When your retinoscope beam just hits the edge of the pupil you will either notice the reflex creep in a little from the edge, or you will immediately see the pupil fill with light. Have a look at the clinical pearls page of the online retinoscopy manual for a diagram of this.

Question: How do you determine the axis with a spot retinoscope?

Answer: Although the retinoscope's light is a spot when you move it across the pupil it still produces a reflex that is a line within the pupil. You want to align the that reflex's line so it is exactly perpendicular to your retinoscope's motion.

Question: How can we manage retinoscopy in eyes with nystagmus?

Answer: Best to try to find the null point of the patient.  The null point is the direction of gaze that reduces the nystagmus the most and then perform retinoscopy with the patient in that position of gaze.  It can be tough with nystagmus you just have to do your best.  Some times a nystagmus may lessen with one eye is closed so you could try to fog a lot or close one of the eyes if that helps to reduce the nystagmus.

Question: Is the ret reflex in an African patient more dull than in a Caucasian patient?

Answer: I do not believe so.

Question: Why scissoring reflex in keratoconus?

Answer: Because of the extreme cornea curvature/steepness of the cone there are multiple meridians across the cornea (it is not a perfect sphere or oblong shape) causing scissoring

Question: When I use retinoscopy rack have I cover one eye?

Answer: No you do not have to cover an eye if you use retinoscopy rack as you need the patient to look straight ahead at a target. If you have one eye covered, the eye you are testing will focus on the retinoscope which will cause the patient to accommodate. Also, if the patient is looking at the retinoscope you need to remove a special working distance value to find the prescription for infinity (see the retinoscopy handbook online to read about Mohindra retinoscopy which is performed on infants monocularly and in the dark). In normal/static retinoscopy you need to ask the patient to look into the distance the entire time in order to control accommodation and to find the correct distance prescription. This is the least effective way of controlling accommodation in people with active accommodation so you may also decide to cyloplege the patient to suspend accommodation.

Question: Do you ret one axis with the sphere and the other with acyl?

Answer: Yes, in a phoropter, I perform retinoscopy at one meridian and neutralize with sphere lenses.  Then I got to the second principle meridian and neutralize with cyl lenses. When using a trial lens frame I do not. When using a trial frame I neutralise the most plus meridian with a sphere, leave the lens in and then neutralize the second meridian with another sphere lens. This makes it easier to calculate the difference between the two meridians (the value of the second sphere lens will equal the difference of the two meridians and therefore the power of my final cylinder lens). Once I have successfully neutralized both meridians, I keep in the trial frame the first spherical lens and swap out the second lens for a cylinder lens placed at the correct axis. The reason I do this is that it is difficult to correctly insert cylinder lenses in quickly and accurately during retinoscopy, especially if you are working in a dim environment.No you do not have to cover an eye if you use retinoscopy rack as you need the patient to look straight ahead at a target. If you have one eye covered, the eye you are testing will focus on the retinoscope which will cause the patient to accommodate. Also, if the patient is looking at the retinoscope you need to remove a special working distance value to find the prescription for infinity (see the retinoscopy handbook online to read about Mohindra retinoscopy which is performed on infants monocularly and in the dark). In normal/static retinoscopy you need to ask the patient to look into the distance the entire time in order to control accommodation and to find the correct distance prescription. This is the least effective way of controlling accommodation in people with active accommodation so you may also decide to cyloplege the patient to suspend accommodation.

Question: How do we neutralize a scissoring reflex?

Answer: You keep your attention to the center of the pupil, keep the motion of the retinoscopy quick and try your best to bracket the prescription.

Question: How do you refract in patients with nystagmus?

Answer: Best to try to find the null point of the patient.  The null point is the direction of gaze that reduces the nystagmus the most and then performs retinoscopy with the patient in that position of gaze.  It can be tough with nystagmus you just have to do your best.  Sometimes a nystagmus may lessen with one eye is closed so you could try to fog a lot or close one of the eyes if that helps to reduce the nystagmus.

Question: Is there any formula to calculate the power for working distance?

Answer: It is simply the dioptric power of the light from the retinoscope at the distance the skill is being performed at. Clinicians always use a working distance of 50cm or 67cm because the diopter power of those working distances are whole numbers. (50cm = 2.00D working distance; 67cm = 1.50D working distance)

Question: If we use cycloplegic drops how do we figure it in the calculation?

Answer: You typically get more plus with cycloplegic refraction.  Sometimes a patient does not need all that plus. Read the retinoscopy handbook online for a small discussion on the value of prescribing a full cycloplegic refraction.

Question: When seeing patients left eye what should be the examiner's eye & hand to hold the scope?

Answer: Left for the patient means the examiner should be holding the retinoscope in their left hand and using their left eye. This is because you want to be in line with the patient's visual axis and you do not want to block the patient's focusing eye (right eye) with your body.

Question: Which is better for children static or dynamic retinoscopy?

Answer: I perform static if the child is attentive and able to look behind me at a target (mum/dad, a video, a colorful toy, etc). I only use dynamic Mohindra retinoscopy when the child is an infant and so I am having difficulty keeping their attention focused in the distance. Dynamic Mohindra retinoscopy is not as reliable as static retinoscopy so I prefer static retinoscopy in attentive children. However, dynamic Mohindra retinoscopy is a close enough estimate of the prescription if it is the only method you were able to get a result with. If I wish to assess the patient's accommodative system (if there is a lead or lag of accommodation) I use dynamic Monocular Estimation Method (MEM) retinoscopy, which is not covered in this lecture, but will be at a later point in the year with another faculty member from the New England College of Optometry.It is simply the dioptric power of the light from the retinoscope at the distance the skill is being performed at. Clinicians always use a working distance of 50cm or 67cm because the diopter power of those working distances is whole numbers. (50cm = 2.00D working distance; 67cm = 1.50D working distance)

Question: The working distance is it a minus sign or you just subtract the working distance?

Answer: It is divergent light which has power coming out of the retinoscope.  Divergent light has negative power.  Therefore, to find your final net prescription you add the power of your lenses and the negative working distance (NET PRESCRIPTION = lens power + -2.00D, therefore, NET PRESCRIPTION = lens power - 2.00D). Take a look at the retinoscopy handbook online for some examples of calculations.

Question: When my streak is horizontal. I am scoping verticle meridian. Then my prescription axis is?

Answer: If your streak is aligned along 180 you are correct that you are assessing the 90 degree meridian. When writing your prescription the axis is the meridian of the sphere. Take a look at the retinoscopy handbook online for some examples of this.It is divergent light which has power coming out of the retinoscope.  Divergent light has negative power.  Therefore, to find your final net prescription you add the power of your lenses and the negative working distance (NET PRESCRIPTION = lens power + -2.00D, therefore, NET PRESCRIPTION = lens power - 2.00D). Take a look at the retinoscopy handbook online for some examples of calculations.

Question: Would you say arm's length is the same working distance at 67cm?

Answer: On average an arm's length is close to 67 cm, but he should be measured for each examiner with a ruler - ask a fellow clinician to measure the distance for you so you know you are performing at the correct distance. We strongly recommend you tie a piece of string that is 67cm long to your retinoscope when you are beginning to learn the technique so you can check your working distance is correct. After a while, you will not need the string as you will have a good feel for it.

Question: Can I calculate refraction only with a sleeve position?

Answer: No. You can with the distance you perform the retinoscope at for myopes but not based on sleeve position.

Question: Do you prefer to fog both eyes or the eye only? And how much myopic power that you will not put in the fogging lens?

Answer: You only need to fog the left eye when you start retinoscopy.  Once you have completed the right eye because you have reached neutrality with the working distance lens still in, the patient is looking at the distance target fogged when you assess the left eye. For this reason, complete retinoscopy on both eyes before removing the working distance lens.

Question: How does the reflex of a person with retinoschisis look?

Answer: Out of scope of lecture.  Retinoschisis is typically a peripheral retinal finding and therefore not seen during retinoscopy.  The patient needs to be dilated.

Question: Is it possible to achieve neutrality and yet some reflex movement?

Answer: Not really

Question: Should we rely on autorefraction to determine the axes or meridian of cylinder?

Answer: Autorefractors can be wrong.  It can be helpful supportive information to what you find on retinoscopy though.

Question: According to you which is the best method Plane or streak?

Answer: Depends on personal preference and the equipment you have available to you.  I use a streak retinoscope, not a spot retinoscope because it is what is most available here in the USA. I do retinoscopy in the plane mirror/sleeve down position mostly, but this is a personal preference. The most important thing is that you are consistent - always perform with sleeve down or up - so you do not get confused. Once I am at neutral and I want to confirm this, I will move the sleeve to the up position expecting to still see neutral.

Question: Is it ok to ask dilated pt to look at me while refracting him?

Answer: You would need to alter your working distance power.

Question: Do you use cycloplegics for all kids or in special cases?

Answer: I only use it in kids I am unable to correct to 20/20, have an ocular misalignment on cover test or demonstrate a fair amount of hyperopia on dry retinoscopy say +2.00

Question: How pt focus at distance and light is at the visual axis at the same time so interfering with far point?

Answer: They focus with the eye that is not having the streak shined into their eye. You must make sure you are not blocking the view of the other eye with your hand, head or body.

Question: So I detect (the most - or the least + only when using 9sph cyl technique? Not double sph tech?

Answer: Correct.

Question:  When you do a dynamic refraction, what's up with the working distance?'

Answer: I perform static if the child is attentive and able to look behind me at a target (mum/dad, a video, a colourful toy, etc). I only use dynamic Mohindra retinoscopy when the child is an infant and so I am having difficultly keeping their attention focused in the distance. You use a working distance of 50cm which is equal to -0.75D for infants and -1.25D for toddlers. Dynamic Mohindra retinoscopy is not as reliable as static retinoscopy so I prefer static retinoscopy in attentive children. However, dynamic Mohindra retinoscopy is a close enough estimate of the prescription if it is the only method you were able to get a result with. If I wish to assess the patient's accommodative system (if there is a lead or lag of accommodation) I use dynamic Monocular Estimation Method (MEM) retinoscopy, which is not covered in this lecture, but will be at a later point in the year with another faculty member from the New England College of Optometry.

Question: How many cylinder power calculation on maximum? Today I examine + 12.D cylinder at the Axis of 75.

Answer: I have never seen 12D of cyl.  I have never seen over 7D of cyl.  Glasses can not be made with that much cyl.

Question: After determining the spherical component during retinoscopy, before you scope for cylinder component in the other meridian. Is Sph lens removed or kept in the trial frame?

Answer: When using a trial lens frame I do not. When using a trial frame I neutralise the most plus meridian with a sphere, leave the lens in and then neutralise the second meridian with another sphere lens. This makes it easier to calculate the difference between the two meridians (the value of the second sphere lens will equal the difference of the two meridians and therefore the power of my final cylinder lens). Once I have successfully neutralised both meridians, I keep in the trial frame the first spherical lens and swap out the second lens for a cylinder lens placed at the correct axis. The reason I do this is because it is difficult to correctly insert cylinder lenses in quickly and accurately during retinoscopy, especially if you are working in a dim environment.

February 27, 2018

3 comments

  1. After determining the spherical component during retinoscopy, before you scope for cylinder component in the other meridian. Is Sph lens removed or kept in the trial frame?

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