During this lecture, the doctors discuss and share their experiences and recommendations to get the most from your clinical examinations and from your diagnostic lenses. In this interactive, panel-based session, the experts discuss how to use the correct techniques to maximize your anterior segment, retinal, and pediatric evaluations. The speakers review the fundamentals of the critical lenses in a case-based format with key takeaways for all eye health professionals.
Lecturers: Dr. Inder Paul Singh, Dr. Suber Huang & Dr. Donny Suh
[Donny] Good morning, everybody. We’re extremely excited to have this webinar on tips and pearls on how to do eye exams using various lenses. I think this is going to be very clinically relevant and practical for many of you. Let me just introduce our co-speakers. First, Paul Singh, he’s the president of The Eye Center of Racine and Kenosha. And he’s a surgical instructor at the Chicago Medical Center. And he’s going to be talking about the importance of gonioscopy and pearls for evaluating the optic nerve via slit lamp biomicroscopy.
And then Suber Huang, Dr. Huang is a CEO of the Retina Center of Ohio. He’s a voluntary assistant professor at Bascom Palmer Eye Institute at University of Miami, and is the past president of the American Society of Retina Specialists. And he’s the editor-in-chief of ASRS Retina Image Bank. And he’ll be talking about examining the eye, tips and tricks of retinal examinations, mostly focusing on adult patients.
And my focus is going to be on pediatric and infants for ROP. First, I don’t have any financial interest to disclose. And I wanted to thank you for your partnership with Orbis. As you know, we’ve been around since the 1980s and we travel all over the world. Without your partnership and without your support, this would not be possible.
The first question I’m going to ask is do you use indirect ophthalmoscope on a regular basis? There are many things that we take for granted, that in many places around the world an indirect ophthalmoscope is actually a rare commodity. And people don’t have it or they may actually just have one for the entire clinic. People have to share. I was just going to bring that up. I’m going to say my favorite lens is to look at the fundus is, and I think that many of you, many places around the world that I have traveled, most people just use 20 diopter lens. But I just wanted to let you know, through our talk I think you’re going to realize that there are actually many different types of lenses out there. There’s a 20, 28, 30, 14 diopters, or 15 diopters. And we’re going to talk about the pluses and minuses of those.
And then my favorite lenses to look at the optic nerve with a slit lamp is? 90 diopter, 78 diopter, Super VitreoFundus, and SuperField. Again, look at the fundus using a slit lamp, there’s different types of lenses. And I also want to talk about that a little more in detail.
After having said that, I would like to just first credit Mr. Hermann von Helmholtz. In 1950s, he actually gets the credit for developing the ophthalmoscope for the first time in the 1850s. As you can see, obviously, you need some type of light source. And back then, they used a gas lamp, as you can see here, as a light source to look at the fundus. I think they were just fascinating. And since the 1850s, actually, various inventors continue to improve it. And they’re actually, I actually tried to list them all, but it was just too many to list.
Let me just summarize it by saying, in 1945, what we wear today was finally developed. Binocular indirect headband ophthalmoscope, that’s what it was called. And various people get credited so I didn’t want to leave anybody out. Since that time, many improvements have been made in terms of adjustable interpupillary distance, portable power packs so you can walk around, adjustable mirrors, dust-sealed optics, and then red-free and cobalt blue filters.
Then, after that of course, we have the video indirect ophthalmoscope which we use in the Orbis airplane to train our trainees. And this is very nice because the observers can watch what the examiner is looking at while the examiner is looking at the fundus and it can help and guide and teach, so it is a great teaching tool.
Also, around the world, people are actually using phones. And there are creative ways to use the phone to look at the fundus. And we’re going to actually going to talk about the different types of lenses. But here’s a nice invention that’s actually being used to look at the fundus to do ROP exams and that’s how they’re documenting the ROPs in South America and, actually, in Mexico. And this is what we do in our clinic here, we use the phone. We just hold it and look at the fundus and take pictures. We’re actually developing a new device that looks like this right here. But there are many creative devices out there.
Rule number one is that learn what you are using. Look at each part and see what each part do, and just play with it. Especially for the residents, take your time and feel free to take it apart and put it back together. Because it’s actually not that complicated a device. It’s just basically a light source with a couple of condensing lenses.
How do you examine pediatric patients that are not very cooperative? I don’t have any particular tricks, I’ve been doing this for a long time. Just have some distraction toys. Obviously, you’re examining the kids in a dark room, so something that lights up. I think it’s extremely important to have it at a distance. And then second, it is very, very important that your exam starts when they come into your office. Make sure you have a front desk staff, technicians, everyone in the entire clinic, having a very positive and friendly culture to put the patients at ease. I think this is very, very critical.
This is a resident, who’s actually Kevin, who’s examining the patient here. It’s very important, for pediatric patients, when you’re examining the left eye, use your right hand so that you’re out of the way so that the patient can actually watch the movies or watch the toys. When you’re examining the right eye, use your left hand, so you’re out of the way. With adults, we don’t really do this, you actually use one hand that you’re comfortable with and then examine both eyes. But for pediatric patients, you do not want to occlude, you don’t want to obstruct their visual axis. It’s very important that they’re able to see so that they don’t get nervous, they don’t get anxious. And I just feel badly these days, because on top of all that, we have to wear this mask, and so it’s very intimidating for a lot of the patients.
Some of the other tips, make sure you raise the chair or else you’re going to acquire this bad posture that’s extremely bad for your ergonomics. Raise the chair to the same eye level and if you cannot do that, have the child sit on mom’s lap, so that they’ll be raised. I think that’s extremely important for longevity.
Then you don’t need the entire intensity of the light, lower the intensity. Then larger aperture, like this knob right here, you can change it and change the aperture of the light spot. And usually we use the fully dilated pupil, use the larger aperture. For the smaller pupil, use a smaller aperture. Just play with it. And then, diffuse light filters are available on all indirect ophthalmoscopes and also there’s a yellow filter as well. And these things actually can decrease the illuminations and make it less light sensitive to the patients. The image quality deteriorates slightly, but for the comfort of the patient, to get more information, it may be helpful.
In terms of the lenses, there are many types of lenses out there. It comes in different powers: 20 diopters, 15 diopters, what is that? And as we all know, from our optics, the diopters is equal to one over the focal length. Here’s what the lenses look like and whatever the focal length is, that focal length will determine the power of the lens in terms of diopter. For example, 20 diopters will give you a certain field of view. These slides, by the way, is available to you and you can look at it later. As you can see, the smaller the number, it actually gives you a smaller field of view, but it gives you a higher magnification. It’s a trade off.
Then also, the working distance. Depending on what lens you’re holding, the working distance changes. For example, for 20 diopters, remember the diopter is one over the focal length. The working distance is where you’re holding the eye away from the eyeball, the working distance is basically your focal length. It’s very close to, or if not exactly, the focal length. For the 20 diopter, it’s one over 20, so that’s 50 millimeters. And as you can see, higher the power, you’re going to have to hold it closer and closer. That makes sense because you see the focal length gets closer and closer as the lens becomes more convex. As the lens becomes flatter and less powerful, then you hold it further and further away. And that is what gives you that magnification by you moving it further away.
And also, the lower the diopter lens numbers, the lower the field of view and higher the magnification and the opposite, vice versa, we just talked about that. And to examine the interior segment, or the cornea. If you want to have a magnified view, then what you do is that you hold the same lens and you move it further away from the cornea, or the eyeball, then you move closer. The lens gets closer to you and then you move closer and that’s how you magnify the image and move that focal point to the anterior segment so you can see a magnified view.
Different lenses functions. Why do we have so many different types of lenses? As a matter of fact, there are actually many, many out there, depending on the companies. Probably, I’m going to say, there are, Suber Huang, Paul, come correct me, but probably I’m thinking about 50 different types of lenses out there. Why are there so many? Because it has a very specific purpose depending on what you’re looking at and the field of view and the magnifications that you want, you can actually select the right lens. For example, the wide field lenses can help you just get a large area quickly and ideal for general diagnosis as you first pass. And then higher magnification, or the lower diopters that we have talked about, if you want to see a very particular area like optic nerve, or the macula, or a retinal lesion, then you could use a lower diopter lens or with the higher magnifications. And of course, if you’re using a slit lamp then these will change.
The right side. Just in general, make sure you hold the lenses correctly. If you have a Volk lens like this, then you want to have the bottom of the letters point toward the patient and the top toward the examiner. This is extremely important. Whatever lens that you’re using, actually, this is pretty much the standard. The bottom of the letters has to point toward the patient and the top of for the examiner.
And then how do you clean the lens? Clean the lens with warm soapy water and then dry using a lint-free soft cotton cloth clockwise so that you don’t accidentally loosen the lens ring. And it is recommended by these companies that you don’t use microfiber cloth over and over and over because over time they can actually collect dirt and dust which can damage the coating of the lens.
For small babies with poor dilations, these babies with very dark eyes, especially when I go to Africa and India and Asia. Sometimes the pupils, they just don’t dilate very well. Then what do you do? Then you use higher power lenses like 28, 30, or 40 for small pupils. And use these small, like this right here, this knob at the bottom, you can change the aperture. And also you change it to a smaller aperture light beam. And then on top of that, you can use the narrow mirror angle. I apologize, the aperture knob is usually on the side and the mirror angle is, actually, that’s what it is right there, so you can actually change it. And you can actually make the mirror angle narrower. And that’s how you can look through the smaller pupil.
How do you examine the patients in the NICU? And what is the ideal lens? Typically most people use, around the world, 28, 30, or even 40 diopters. I’ve actually seen people use 40. And some people, they’re just used to using 20, so they just use 20, which I think is okay. I typically use 28. 40 diopters is great. 40, 28, 30, is actually ideal for small pupil but also provides a wider field of view. You’re just looking for that peripheral exam. It’s actually acceptable and it’s very quick to scan. And 30 is an excellent alternative if you want more magnifications than 40. And both 30 and 40 have a smaller ring so you can actually get closer to the baby’s face. That, actually, sometimes can be helpful.
But 20 diopter or 28 may be more beneficial or advantageous for you if you have babies, these babies with the nasal cannulas, or CPAP, or things like that, and they just have a lot of things around their face, and you can’t get the lens close enough and you actually need a further away. Then the lower power with the higher magnification may be needed.
From my experience, I use a 28 for examining ROP babies. And then I carry 20 with me and if I actually want to look at something more in detail. And then if I’m concerned about the optic nerve, or there’s anything small, the small areas I want an even higher magnification. And sometimes I actually pull out my 15 diopter, which I occasionally use. There’s a single-use version available, which actually I’m going to show you. It actually comes prepackaged like this. The single-use versions are available and often used and recommended for mitigating infections and risk in premature babies. And for these babies in the NICU, I recommend washing your hands. Washing hands is mandatory with NICU babies. Some do wear gloves and some do not. I’m going to recommend that you wear gloves in the NICU. And some people do not feel that this is very important but I do think, especially these days with the pandemics, I changed my practice. In the past, I actually did not wear gloves, but now I do on all babies.
ROP lasers. BIO lenses are safe for lasers. And 28 or 30 diopters are preferred for the treatment. And again, if you prefer to, I don’t autoclave them, I don’t sterilize them, but I do clean my lenses with alcohol before I treat the babies in the NICU. And if you prefer to use an autoclave, only use the autoclavable lenses. It’s very, very important.
When you get a blurred image, what do you do? How do you improve the image? The ring size and the working distance actually have to be perfect. Because each lenses have very specific working distance. So if you’re not working at that specific working distance, for example for 20 diopters of 50 millimeters, then the image is going to be blurred. And also, for people with a small hand, it’s actually hard. Small hands trying to hold these bigger lenses is very difficult. Try to find a lens that you feel very comfortable, especially people with small hands. Or even people with big hands. I think you have to feel comfortable. And these lenses, also, for people with small hands, also these numbers with the higher numbers have a shorter working distance so you can actually rest your fingers on the patient’s forehead or on the brow to stabilize it. So that actually is another tip that I can give you.
And also looking at the periphery, every lens has a unique working distance we just talked about. And if you’re away from the working distance, if you’re out of the way, the images get clipped and if you’re too close to it then the peripheral view appears dark and unclear and it’s out of focus. You’ve got to hold the BIO lens close to the eye, then move slowly away until you’re able to field the image within the lens, the entire field.
That’s my presentation and we’re going to have, I think, Dr. Singh is our next speaker.
[Paul] Thank you, again, for the opportunity. I love video editing so I’m going to start us out with a little video here.
That’s an ominous beginning. (laughs) I appreciate the opportunity to present. I’m actually going to talk about gonioscopy and the importance of optic nerve evaluation. In glaucoma, of course, the optic nerve is what it’s all about. I’m from Wisconsin, so good morning from the Wisconsin area. I appreciate, again, for those of you out in different parts of the world, I do also wear a cheesehead sometimes, it’s over my turban. We’re known as the cheesehead state. We love our cheese and we like to deep fry everything out here, as well. Welcome, from Wisconsin.
Why is gonioscopy so important? What’s the impact now? I think, historically we’ve seen that gonioscopy does give us so much information about the angle, of course. Is it open? Is it narrow? But even as recently, besides looking at secondary glaucomas, there’s such a resurgence of laser trabeculoplasty, SLT and others, where you do have to understand what is a pigmentation of a T.M.? Can you see enough of the trabecular meshwork? And, of course, with MIGS, micro minimally invasive gonioscopy surgeries with the stenting and the viscodilating procedures in trabeculectomies that we do, it’s important, preoperatively, to really have a good understanding of what’s the angle, what’s the pigmentation? Do we have PAS? Are we able to address the entire 360 when we can go into surgery? To really prepare for surgery, it’s very important to perform gonioscopy.
Just a brief overview. I’m going to go through a lot of information in a very short period of time, so I apologize if I go fast but I want to make sure we get through everything. But it’s important to realize there’s two different methods of performing gonioscopy to look at the angle structures. There’s direct and indirect gonio lenses such as the Koeppe lens up top here. And that’s the lens that gives us basically the internal angle reflection. Light reflection. It allows us, with this type of lens, to look directly into the angle. But the problem with this type of technique is that you need to have an external light source, you need to have an external loop or some type of imaging for this type of procedure. Kind of like an indirect like you saw earlier with Donny’s presentation.
For a lot of us in the clinic, it’s really difficult to lie a patient down, put the lens on the eye, try to get an external light source for these types of patients. But for kids, where it’s difficult to get in the slit lamp, I think this a fantastic way to approach the angle. Give you a nice wide view, it’s easier from a position perspective.
The indirect view, which is what we use normally, in the office with our lenses, is what gives us the view that’s indirect, is a mirror that bounces the light so it gives us an inverse view of the angle. So we’re looking at the top of the lens, we’re looking at the inferior angle, so it’s important to recognize that. But it does make it more easy for the patients and for the provider as well, which we’ll go through some, and show you some of the pictures here.
This is a direct view, you have to have an extra light source, biomicroscopy, portable slit lamp we’ll say. And then you have the lens on the cornea and you have the patient lying down with a coupling agent and you can basically, after anesthetizing the eye, move around in a position that you feel comfortable to look at any part of the angle. So it’s easier to look at both angles at the same time. You can put lenses on both eyes and compare pretty quickly, you can move around the eye much more easily. So it does give you some advantages. But again, the practicality part of it makes it more difficult for a lot of providers to incorporate this in their offices.
Where direct gonio has really helped a great deal is in the OR. For those of us and those of you out there who are doing micro and minimally invasive glaucoma surgeries like the eye stent or Kahook dual blade or goniotomies, whatever you do in your world, this is what we use as a nice direct view. And this is where we are tilting the head for the most part and putting the gonioprism on, getting a beautiful view of the angle. And we’re going to go through some of the angle structures and what we are actually looking at when we use these lenses.
The indirect gonio lens is basically allowing us to perform gonioscopy with a head sitting up at the slit lamp. And there’s different types. There’s a single mirror, there’s a 3 mirror, there’s a 4 mirror, there’s ones that have a handle, as you can see on the top left. The advantages of these lenses allows us, again, to use at the slit lamp. The 4 mirror lens does not require any kind of coupling agent like carboxymethyl cellulose or methylcellulose, which makes it easier from an efficiency perspective. Put a drop in the eye, anesthetize the eye, and put the lens on the eye, you can go ahead and just take a look at the angle pretty quickly. So it’s easier to pull it in and out. Versus with the 3 mirror lens, like the Goldmann 3-mirror lens, it does have three mirrors but it does need a coupling agent. And so you have to couple, put the ointment on the lens. Usually we use a GenTeal Gel type of a situation, or even a viscoelastic can work as well. If you use carboxymethyl cellulose, that can get irritating to the cornea, so you want to wash it out very quickly from the eye after you use it.
But the idea of this lens is it does allow you to really get a nice, nice contact with the ocular surface. And it has three mirrors, two of the mirrors could look in the periphery of the retina, and the center mirror can also look, as well, at the optic nerve. Good view of the retina, as well as one mirror that you turn to look at the angle as well. What’s also nice about this, if you have a heavy hand, let’s say you like to push very hard and the patient is not as cooperative sometimes, with a 4 mirror lens, because there’s no coupling agent, it’s easy to push too hard and to indent. That’s a benefit of it, you can indent and we’ll talk about that. But sometimes you get corneal folds. With this type of 3 mirror lens and having a coupling agent, it’s more difficult to push too hard on the cornea to cause a difficult view. It’s a little easier for some people to get that nice view as well.
The 4 mirror lens comes in a hand held little handle up on top or you have a larger lens in the bottom here where you hold it on the eye. Either way, on the eye. What’s nice about this lens, again, is you do not need a coupling agent. Which is nice, again, from an efficiency and flow perspective. What’s nice about a 4 mirror lens, is it allows you to perform indentational compression gonioscopy, which we’ll talk about in a second. In other words, if you have an angle that’s narrow and you want to decide, is this angle potentially going to be a benefit from an LPI, peripheral iridotomy, you can put some pressure on the cornea, you’re going to deepen the angle. And you can see is this a plateau iris, is this a narrow angle? And this can help you differentiate that as well. There’s some advantages of a 4 mirror lens.
But what are we looking at when we’re looking at these gonioscopic lenses? This is the angle. For everybody out there, important. Everybody who gets an eye exam, in my opinion, should get a baseline gonioscopic examination. Now, if you have glaucoma, it’s imperative. And what we have to be looking at is at the top here, Schwalbe’s line on the top left, this is where the Descemet’s membrane ends, where the cornea ends and the sclera begins. This is the actual anterior aspect of the trabecular meshwork and that’s the line right there. A white line you see anterior to this larger, darker line, the pigmented trabecular meshwork, as you know, where the outflow facility goes through the conventional pathway.
And then here’s the scleral spur which is just below or posterior to the pigmented trabecular meshwork. And on the bottom, this bottom brown line is the actual ciliary body band. Now, it’s important sometimes, if you have a narrow angle, you may see the ciliary body band. You may get confused and say, “Hey, this is an open angle.” Remember, if you don’t know where you are, if you don’t know if this is an open angle or a narrow angle, you see one brown line, try and look for the two white lines. If you see the scleral spur and you see the Schwalbe’s line, if you see two white lines, the T.M. is in between that. Because sometimes trabecular meshwork is not pigmented, it’s not easy to see, and that will give you a better understanding is this someone who has an open angle or more of a narrow angle?
Again, what is a narrow angle and how do we diagnose it with a gonioscopic view? If you don’t see those angle structures you see in this picture here, you see some synechiae, some scarring in the iris to the periphery of the angle, there’s no structures. You can see this is a closed angle here. And what do we utilize and how do we differentiate the different angles and which patients need a peripheral iridotomy? Well, you can use different systems. One at the bottom here is a Shaffer ray, which is a very commonly used system looking at how open the angle is from the T.M. to the cornea. And you can look here, if you see about a 20 degree angle or less, that’s likely going to be someone who could occlude and more likely need an LPI. If it’s greater than 20 degrees, you’re more likely going to open and probably can avoid needing an M iridotomy to open the angle. I think another way to look at it is, do you see trabecular meshwork? For me a clinical pearl, if I see trabecular meshwork 360, I’m much less stressed about needing an LPI. If I see T.M. in only one or two quadrants or less, that’s a patient who’s usually ending up needing a peripheral iridotomy most likely as well.
One thing, also, this is something here called a corneal wedge technique. You could put the slit lamp about 25 degrees in an off axis or oblique position. And you see two light reflexes and they merge at the scleral spur. And this corneal wedge defect can allow you to understand and see Schwalbe’s line, it highlights Schwalbe’s line very nicely as well. So that’s something you can think about doing when you’re trying to understand where Schwalbe’s line is, that corneal wedge technique can help a great deal as well.
But I think it’s important when we talk about gonioscopy, especially if you’re using a 4 mirror lens, to think about indentation gonioscopy. This is a crucial way for us to differentiate is someone having an open angle or narrow, but can they benefit from an LPI? Is this a plateau iris? Where the iris is inserted more anteriorly versus this is a secondary angle closure glaucoma. What’s happening, is there PAS or not? And what I mean by that is on the left, you see here a view of the angle, you can barely see the trabec mesh, this is Schwalbe’s line, the pigmented line up there, see Schwalbe’s line here. And you see T.M. barely.
Now, if you look, you can see how you can deepen the angle here by pushing on the eye. When you push on the eye, you push aqueous and you change the lens iris diaphragm complex, and you can push it out and you can actually deepen the angle. Look at the bottom here before and after when you indent, it allows you to see more of the angle. This is a great way to differentiate plateau iris from a narrow angle.
I want to show you a video, one of the videos I just made. This is from last week, a patient I saw here. And what I’ll show you is basically what happens when you have a narrow angle. Here’s an angle where I’m actually going to go ahead and show you here. If I don’t push, it’s hard to see. When I push you can see there’s deep, let go, it’s hard to see angle structures here. Let me see if I can show you there. Deepen, push there, relax. Relax, then I deepen. And there you go, see I deepen, now I can see this brown line, see a line, that’s the scleral spur here. And before, when I don’t push, I can’t see it. So there you go. I cannot see it, when I’m relaxed, I’m not pushing too hard, I can’t see anything more than bare trabecular meshwork. When I push on the eye with doing indentation, I can actually see, there you go. When I push harder, you can now see a line below that brown line. That’s the scleral spur. This is someone, who with indentation gonioscopy, by pushing on the eye with my 4 mirror lens, I was able to deepen the chamber, this is a patient who would definitely benefit from a LPI or laser peripheral iridotomy as well.
Dynamic gonioscopy is important too. Looking with your gonio prism, if you want to know if someone has narrow angles or open angles, what’s the relative contribution of a light. As you know, we shine a light, pupil comes down, that can deepen the angle. LPI patients tend to, or people with narrow, tend to have more symptoms, potentially when it’s in a dark room because you’re occluding the angle more by pushing the iris to the periphery when you dilate the pupil. If you do dynamic gonioscopy, you can turn the lights down and then turn it back up. You can see what happens to the iris and you can see how the angle opens when you watch this. Open it, now see how the iris moved. And this is a way to see how open the angle is and how narrow it is based upon lighting. This is why, when I see this happening, this is another patient who might benefit from an LPI as well. Where a patient’s come in saying, “I have redness and irritation, light sensitivity when I’m in a movie theater.” This could be one of the reasons why. With lighting you can see the effect of the angle just based upon light. When you’re evaluating patients with the slit lamp, try to turn the lights down as much as you can, room lights down, especially if you’re worried about narrow angles, that can help you understand the true impact of that angle as well.
Another way to differentiate narrow angle versus, let’s say, something called plateau iris, is this double hump. You see those two arrows, you see this two hump system. Plateau iris, again, is an anterior insertion of the iris. And what happens, in general, the ciliary body. And what happens is it does not benefit from an LPI. So you still most likely will try a laser peripheral iridotomy in these patients. But if you have a plateau iris, you see these double humps M sign and the LPI doesn’t work, that gives you that diagnosis of a plateau iris. And these are the patients who may need an iridoplasty as well as pull the iris back away rather than just putting a hole to prevent a block. And so that’s a nice little benefit there by looking at it using a gonioscopic view.
There’s other secondary glaucomas that are really important to utilize gonioscopy for. Pigmentary glaucoma, now they’re not as obvious as this. This is one of the favorite pictures I took on the way left there. That’s a real life picture, I promise, of a transillumination defect of the iris in a pigmentary dispersion syndrome patient. and you can see all those beautiful TIDs there. You see K spindles, there are pigmentation on the endothelium of the cornea in the middle. On the right is a gonioscopic view, this is not one of my pictures. But it’s a gonioscopic view of a beautiful, dark, dark pigmented T.M. So it’s nice if you don’t have those big, big, big Krukenberg spindles here or transillumination defects on the left, just look at the angle and see a dark, dark brown line can give you that diagnosis of a pigmentary dispersion patient. These patients do very well with a laser trabeculoplasty as well.
It’s also important for other conditions like pseudoexfoliation. patients who have narrow angles, a lot of times with those patients, the zonules become weaker, it can push the lens forward and it can cause a secondary angle closer. You can also get signs like Sampaolesi’s lines, which is a pigmented line anterior to Schwalbe’s line. And so these are patients whether you see pseudoexfoliation, see that dark, pigmented line, don’t be fooled that is not trabecular meshwork, that is actually a pigmentation anterior to the Schwalbe’s line. Again, these are things that you can look at when you’re doing a gonioscopic view in helping with diagnosis but also managing these patients.
I think angle recession’s another great diagnostic, gonioscopic views give us a good diagnosis for angle recession. Patients who have traumatic disease, whether they’ve had some trauma, you see a separation between the longitudinal and circular muscles of the ciliary body. You see this deepening, you see this wide, wide, wide angle and you see actually a white line or a very wide band of a ciliary body band. And when it’s very wide like that, let’s say in a certain clock hour, maybe at two or three clock hours, even larger, that can lead to a secondary glaucoma. And it separates the actual outflow pathways and therefore you get a significant pressure spike in these patients. Angle recession glaucoma is something you can also diagnose very nicely with gonioscopic views.
Neovascularization of the iris, really important when you’re looking at patients with diabetic retinopathy, patients with vein occlusions, et cetera. You can get, again, anything that’s going to stimulate vascularization growth factor. Important to look at the angle. You can actually save some of these patients from developing neovascular glaucoma. A patient comes in with a retina, a bad PDR, has a lot of, has not had anti-VEGF injection. Their pressure’s maybe going up, you see all these little red blood vessels in the angle, do an anti-VEGF injection, you can reverse those, regress those vessels and save a patient from getting a tube or a trab and preventing scarring.
Because what can happen if you don’t address these vessels in the angle? Guess what, you get synechiae. Peripheral anterior synechiae, which is basically scarring and iris going all the way and opposing to the peripheral cornea there. And you can see it basically blocks the angle and blocks the trabecular meshwork. These patients do not benefit from LPIs, it’s harder to do a laser trabeculoplasty, even MIGS. Surgically you can try to separate them with going to synechiae lysis. But again, it’s not that easy to do as well. So preventing PAS is something that we want to do as much as possible.
That was a quick overview of gonio. I know I spent a quick, quick time there. I think it’s important to recognize how important it is to identify structures of the angle, not just now for the diagnosis of the different types of issues that we have, but also for surgical. With MIGS, et cetera, there’s no doubt an issue there that you need to understand ahead of time.
Now, real quick, I’m going to go through some basic pearls on optic nerve evaluation and then we’ll move on after that.
Remember, structure versus function. We lose structure, nerve fibers, ganglion cells before we lose fields, before we lose function. Especially here, early on. The disc, not just OCT, but the optic nerve evaluation biomicroscopy, can give you so much information on a patient’s potential for developing glaucoma, or having glaucoma, or progressing.
And this is something that I adapted from Dr. Weinreb’s work many years ago. He did something called a forged talks for a different company. And I adapted his talk and adjusted it for this as well, because I love what he did. And he has a 5 “R’s”, five rules.
And first rule is to observe the scleral ring and to see the size of the nerve. Larger nerves tend to have larger cups. So if we have a larger nerve and a larger cup, that tends to be potentially more physiologic than clock otis. And really the average size of the disc is about 1.8 millimeters. What you do is a size of ophthalmoscope is usually the size of a typical optic nerve. If you’re using an ophthalmoscope just to go and look at the nerve, that size of that nice circle can give you a good size of the optic nerve and give you understandings that say normal sized nerve or a smaller sized nerve. And so again, depending on what lens you use, a 60 diopter lens, a 78 or a 90 diopter lens will give you different magnifications.
For instance, if using a 60 diopter lens, it’s a 1-1 ratio, you’re going to get a true size of the nerve. When you want to measure on your slit lamp, you can measure, let’s say, one millimeter, two millimeters, that’s real. If using a 78 or let’s say a 90, I, personally, use a 90 diopter lens, clinically. You have to times it by 1.3. You’re minifying the object a little bit there. Times whatever measurement you get on the slit lamp, times that by 1.3, that’s going to give you the actual size of the nerve. And the reason I use a 90 is because I can get through smaller pupils, I look at the nerves on every glaucoma patient I see, every follow up, looking for will show you disc hemorrhages, some obvious changes. But I do a yearly dilated exam to really document the optic nerve as well. Make sure you understand how to correct it depending on the size lens you use.
This is showing you here, you can take your slit lamp, and you can go one direction for vertical and then you can do your slit lamp for a second horizontal. And that can give you the size of the nerve in the slit lamp. And again, small nerve’s going to be 1.2, 1.4, average about 1.8. And larger above 2, around 2.5. The larger the nerve, the larger those cups can be and become physiologic. If I see a large nerve, like a 2.5 millimeter nerve, and I see a nice, sharp cup like that, a lot of times it’s physiologic. I don’t worry quite as much as a smaller nerve with a larger cup.
The second rule is identifying the neuroretinal rim. In other words, do we have healthy rim or not? And this is called the ISNT rule. I learned this when I was a resident, I loved it. And basically, the inferior rim should be thicker than superior, then thicker than nasal, and temporal rim is usually the thinnest rim. And it’s not a 100% steadfast rule, but you’ll be amazed of how many times you look at a cup, you’re not sure, is this physiologic or glaucomatous, you follow this rule and the majority of the time, it holds true. So for instance here, if you see a patient where the inferior rim from the cup to the edge of the scleral rim here, if that is not as large as superiorly, that’s someone you should be more concerned about as well. And this does, we’ll show you some examples in a few minutes. But it does help a great deal.
When you localize the rim you want to look for things like notching. You see here, a nice circular cup here at the bottom inferely, and in here this is a superior loss here, you see a nice little notch in the rim. If you see a notch, that’s a sign that there’s probably some issues there. And you can see in the side here, a nerve fiber layer defect. The optic nerve here, these nerve bundles, you can see a darkerning, a wedge darkening there. Usually that will correspond to a notch on the optic nerve.
And so it leads me to another rule. The rule three, which is evaluate the nerve fiber layer. You can use a red free, use the green light on the slit lamp, and you can see these white striations, these bright white striations. Using red free, even at the slit lamp, can allow you to understand and identify some of these nerve fibers, that we sometimes we rely so much on OCT. But it’s amazing how much you can see by looking just at the slit lamp with your lenses, you can see loss of those striations that gives you an understanding if someone might have a glaucomatous change. And so you can see here localized loss. The red free image in the left, but you can see here, even on a color photography here, you see a thinning of the rim here, loss of rim inferiorly, but you see these nice two arrows here, this nice wedge defect here. This will correspond, likely, to a superior field defect. And if you get an OCT I’m sure you’re going to see significant loss down there as well and into the ganglion cell complex. Clinically, looking at it, you can see it without having any specialized tests. If you don’t have an OCT or field, this could tell you right away this patient has significant issues there.
Rule number four, examine the region of peripapillary atrophy. PPA can be tough because you have these myopic, tilted disks. It’s hard, sometimes, to evaluate a nerve when you have other issues like myopia, et cetera, or thin sclera. But for the average patient, you can differentiate something called alpha zone atrophy versus beta zone atrophy. And beta zone atrophy basically is the atrophy of the RPE and the choriocapillaris as well. And you start to see these larger vessels right at the edge of the disc itself, and we start to see those large choroidal vessels and you can start to basically identify beta zone atrophy. That will progress over time and that is pathognomonic for glaucoma. Again, if you start to see that, that’s a sign even if you can’t see a wedge RNFL or any obvious RNFL loss there, beta atrophy can help you understand if someone is progressing or not here. And this just shows you here a thin rim and you see a larger beta zone atrophy.
There is a correlation, as the rim thins, the beta zone atrophy increases. When you look with your lens, your 90 diopter lens and you start to see, take pictures, if you start to see that beta zone atrophy increasing over time, even if it’s a hard time to see the cupping itself, that’s a sign this patient might be progressing. And usually RNFL, nerve fiber layer defect, will be associated with that beta zone atrophy over time as well. Something to remember to look at, we tend to forget that atrophy, well that can make a big difference.
Here’s another example too, of a thin rim down below here and this arrow’s showing you these larger vessels and this atrophy right near the rim. That’s the beta zone atrophy we showed you early as well.
Don’t forget looking for disc hemorrhages. Disc hemorrhages are extremely important. And something that I look at the hemoglobin A1C for the eye, for gonioscopy. Just like we have hemoglobin A1C for diabetes, disc hemorrhages can really help identify those patients who maybe are not controlled. And they can be usually in the temporal quadrants, usually. Inferior temporarily or superior temporal. They could be a flame type of hemorrhage like here, they can be more of a diffused blot type of hemorrhage as well. They can be even at the center of the cup, near the entrance of the lamina. But the majority of the time, these disc hemorrhages will disappear within about a month to three months. So they’re not a permanent issue, but it’s nice to see them. That’s why I use my 90 diopter lens everytime I see a patient every four to six months, I’ll at least take a quick glance at the nerve to see, am I missing a disc hemorrhages that I could identify? And that’s a patient who had to say, hey, maybe they’re not controlled quite as well.
Here’s some more examples of disc hemorrhages. They can be small dots so be careful. You may miss these, they may look like a blood vessel sometimes. Or they could be adjacent to one of the veins or arteries here, as you can see here, in this inferior one as well. And then if you look here, up top here, they can look more diffuse like a little shimmer on the cup itself as well. Very important to not forget disc hemorrhages as well. Again, they can last two to three months and they can predict glaucoma. And there’s a number of studies showing that those disc hemorrhages can lead to nerve fiber layer defects, as you see in this picture here, a nerve fiber layer defect coming off of that disc hemorrhage as well. No doubt there’s something to be aware of, especially in normal tension glaucoma patients. They tend to have more likelihood of disc hemorrhages.
A couple examples and I’m done. (laughs) But basically, it’s good to understand. What is normal and what is not normal? Here’s an example of an optic nerve in a glaucoma patient, or is this glaucoma or not? When you look at the scleral ring, look at the size. This is a patient about two millimeter disc as well. Do you see any nerve fibulary defects? Do you see these nice striations of an RNFL here, no bundle lost, not darkening here as well. There’s no prior papillary atrophy, no disc hemorrhage, this is likely a physiologic nerve. Especially if the fields and the pressures are normal, likely more physiologic. And you also see here a very sharply-defined cup. When you see a sharply-defined cup, like someone took a pencil and drew it, that’s more likely to be a physiologic cup more than a glaucoma cup. We see what we call sloping a lot of times.
Here is a patient who has a nerve that looks suspicious for glaucoma and why? Because you see here, almost you see a notch developing here. See some peripapillary atrophy here, see this large, large, there you go, wedge defect. And the inferior rim here is thinner than the superior rim, it doesn’t follow that ISNT rule. And so this is a patient where, most likely, they have glaucoma and you also look at the extent of this large darkening which is a large RNFL defect as well. Again, these are all the different parameters that you look at when you’re looking through your 90 diopter lens, looking through your 78 diopter lens. When you’re looking at the nerve if you have a dilated examination, try to look at all those different factors. How big it is, what is the size of the rim, the distribution of the rim, do we have any bundle defects? Do we see the atrophy and do we have any disc hemorrhages? All of those can really help you to identify and look for progression over time as well.
For the sake of time I’m just going to fast forward here. Again, this is a larger nerve, 2.5 millimeter nerve, good, healthy nerve fiber layer, most likely a physiologic cup, especially if the fields and the pressures are normal.
Thank you so much for the time, I hope that helped give you some pearls for you all out there, appreciate it.
[Donny] Thanks, Paul, thank you. Gosh, this is actually very educational. Suber, please, take it away.
[Suber] Hello, everyone, and thank you Dr. Suh, for the kind introduction and to Orbis and Cybersight for putting on this tremendous program. Congratulations to my co-speakers. I’m going to speak a little bit about the retina exam today. I’m trying to keep it as practical as I can and address some of the issues that have been touched on both by Dr. Singh and Dr. Suh previously. And try to give you some idea of what we look at when we examine patients as a retina specialist.
These are the five takeaways. If you remember nothing else, these are the five takeaways. I’m going to let you know those first. The number one thing to improve your view of the retina is to dilate the pupil. That doesn’t always happen easily, but a bigger and more well-dilated pupil is better. Second, you need to use perfect technique. And technique is like any other technique, it takes perfect practice and you have to practice on every patient you have in order to improve your technique with time. The third is you need to respect the fact that choosing and caring for your equipment is really important. It’s not just the patient and it’s not just the doctor, there’s everything intervening. And learning to use and care and select your equipment for the task that you’re trying to perform is extremely important. Fourthly, you need to know what you’re looking for. If we only just look we may not see. In other words, we may look at lots of things but not look specifically, as just demonstrated in Dr. Singh’s talk, about exactly the pathology that you’re looking for. Having a prepared mind is terribly important. And lastly, no one learns things overnight. It may take an hour or a day or a week to learn, but it will take a lifetime to master and it’s something to keep in mind.
There are several types of lenses that are present. Two important ones are a diverging lens, a concave or biconcave lens with a raised fan out, and a condensing lens or a biconvex lens where the rays are focused by the lens. And these are the ones that are used for diagnostic examinations. These are the best times to use in the retina. In order to see inside the eye, you need to have a light source to illuminate the inside of the eye. And it’s that reflected image that comes back out of the lens and refocused by the biconvex lens to form an image between the observer and the biconvex lens. So the biconvex lens forms an inverted virtual image between the observer and the lens. It floats in the air, if you will, and that gives us a great view but it is subject to all the things in the pathway that are present to create that very important view. If you’re too close to a lens, like a magnifying lens, it’s like a magnifying glass. The image is upright and it’s magnified. But an indirect image, as we said, gives an inverted and backwards view of the indirect lens. But as we’ll see, this is one of the ways that we can look inside the eye.
The lens design is also very, very important. All optical systems have chromatic aberrations, spherical aberrations and these all distort the image. If it’s just spherical you can get an image but there is some distortion as you look at it. A single aspheric lens on one surface of the lens can reduce that distortion. But a double aspheric lens where both sides are tapered, minimizes the amount of distortion that you have. So a double aspheric lens increases the depth of focus so the more the image is in focus, and reduces the distortion of the image to give you an optimum orientation and optimum view. Lenses may have an orientation as previously discussed and it’s very important to use the lens in its proper orientation.
As we discussed, there are many many things that are factors from the doctor to the patient and back again. When we talk about selecting the proper working distance, it’s very obvious, from a practical standpoint, if you’re not at the proper working distance you simply don’t get a good image. Your hands need to be steady and you can steady them either on the patient or a very steady hands by holding it in the area. And you have to have a systematic exam pattern in order to record what you see with the minimum amount of time and maximum amount of clinical efficiency.
Illumination is very important, the amount of ambient light in the room. If it’s very, very dark the light from your ophthalmic scope will be terribly bright. So some ambient light, in most conditions, is actually preferred. It increases patient comfort. Intensity of the light should be used to a level that is comfortable for the patient. But remember being able to see the pathology properly is probably the most important thing. If you don’t see the pathology, we’ve missed our goal.
The lens we’ve talked about, the double aspheric lens and we’ll talk a little bit about anti-reflective coating. These are actually coatings that are in the wavelength to cause destructive interference. In other words, that eliminates glare. And this is an extremely important advance in lens design. We use the appropriate field of view and magnification, we’ll show some examples of those.
And lastly, remember that it’s uncomfortable for the patient. The patient may be fearful or in a case of patients with ROP, they may even have bradycardia or stop breathing. So working with a patient, encouraging them, telling them that they are doing well is very, very important. You want to also be efficient. Lingering on the eye when the light is in your eye can be very uncomfortable. We need to maintain that relationship in order to follow the patient over many years. A smooth corneal surface is important, media opacity is important, and I’ll leave the most important thing again: pupillary dilation.
Every factor contributes.
Why do our lens is needed? Well in fact, they’re not needed to examine the external part of the eye, we do that with a penlight. And using just our eyes alone we can see the external structures. But we can’t see the internal structures because there are not enough reflective light coming out of the pupil. We see it as a dark pupil because there’s not enough light. We cannot see the details of the retina, the retina appears dark. We know that if we have a light source we can get a red reflex, sometimes it’s desired when we’re examining the eye, but it’s undesired in photography. Using a direct ophthalmoscope which has a light source and integrated lenses within the eye, you can have a direct view of the posterior pole. It gives a very magnified view and actually is very wonderful for looking at the optic nerve and some of the structures in the posterior pole. But not necessarily to the peripheral retina, which again appears dark and is difficult to observe the peripheral retina.
There is no stereopsis, so estimating height of lesions is very difficult. For instance, if you try to look at a serious detachment, as asked in one of the questions, you cannot do that because you have no ability to make that to have stereopsis and also you’re very close to the patient. You can see here that the examiner is stabilizing his exam by actually touching the patient’s face. But that is very, very close and in the pandemic era, perhaps it’s better to have a more distant view.
Using indirect ophthalmoscopy, using the lens as previously described, we have a much, much wider field of view where the image fills the lens here and you are at a working distance further from the patient. Indirect ophthalmoscopy is the best technique to examine the peripheral retina, is binocular, it is stereoscopic. So for lesions that are elevated, such as a retinal detachment, or a retinal tumor inside the eye, you can evaluate those more easily.
There’s two different ways to examine the retina, we use both the slit lamp exam, as well as the binocular indirect ophthalmoscope. The slit lamp exam we’ve previously seen to look at interior structures, the patient’s seated and you can view anterior segment, the vitreous, and the posterior segment, and have a detailed binocular stereoscopic view of the posterior pole, with the ability to change the magnification on the slit lamp. The patient can be dilated or undilated. But if you want a good view, just as in all physical optics, a dilated view is better. When you use the binocular indirect ophthalmoscope is used to look at the peripheral retina, from the equator on out to the periphery, even to the ora serrata or even the ciliary body can be viewed using the BIO. Generally, the patient can assist you by looking in a gaze direction and you can use external scleral depression to indent the eye and bring anterior structures more into view. The patient may be laying down or seated, depending on how detailed the exam is necessary. And again the patient is dilated.
The slit lamp exam examination is used to look at the anterior segment and the anterior vitreous which is terribly important as well as the posterior pole. And the binocular indirect ophthalmoscope is used to look at the peripheral retina. In a slit lamp examination, using bistereo microscopy, we can look at the anterior structures including the angle, as well as the interior vitreous, as well as the posterior pole. Here in this illustration, we can see if the slit lamp is moving side to side, not up and down in this illustration. But as you go side to side, we can scan across the macula looking at the optic nerve, here are the nasal retina, here’s the macula, and again you can look at the temporal macula out to about the equator of the eye. The peripheral retina is not visualized well with the slit lamp biomicroscopy without the use of a mirrored lens and an indirect view as previously discussed.
Choosing the right working distance it’s very important. If you’re too close with the lens, the peripheral retina is not illuminated and appears dark. Too far, you have lost the field view. But the correct distance gives you a full image and fills your lens with a correct, sharp image. So the right working distance provide both the widest and clearest field of view.
When performing a BIO examination, obviously it’s important to find the right working distance. We start with the lens closer to the eye and gently move backward slowly until the image fills the eye. This is, as a live photo shows, that can be quite challenging. The patient may move, your hands may move, your head may move, everything has to be just perfect. But in fact, we are looking at vignettes where different areas can be examined and brought into view. And like walking or like many things in life, you quickly find out exactly what is the right working distance for your eyes, the patient’s eyes, and the lens you’ve chosen.
To have a very systematic approach to looking at the peripheral retina is extremely important. We perform a clockwise examination in both eyes. This is one example where we do not go symmetry, going from superior to temporal to inferior. We always go in a clockwise direction. With a reasoning being, you’ll always be able to say where the pathology is as long as you know what clock hour you’re examining. If you have the patient look up at the 12 o’clock position, we’ll know it’s there. If it’s at 2 o’clock, say it’s at 2 o’clock in the right eye, we can precisely describe the pathology. For instance, lattice degeneration from 1 to 2 o’clock, one half this diameter posterior to the ora serrata with atrophic holes and without subretinal fluid. It’s a precise description of exactly what we look at. And we can scribe that as we go all the way around the eye.
I start with the lens close to the eye and move back to find your best working distance. This is something that will become second nature to you and you will automatically find that with practice. But remember to practice perfect exams.
When looking in different areas of gaze, it’s traditional to ask the patient to look in the field of gaze. I typically go by quadrants. I say 12 o’clock and then I say look up and up and out. Look to the left, look left and down, look down, down and right, down to the right, and into the right and up. You notice that I didn’t say look up and right because if you’re looking right, you mention up first, the patient will look up. So it’s important to be systematic and not have any skipped areas. Skipping areas is a critically critical mistake for retinal detachment or anything where you’re looking, any disease where you need to look at every single inch of the retina. And that’s for most of the blinding diseases. You examine the posterior retina last because that’s where the light is most sensitive and you’ll increase patient cooperation if you do so.
Let’s look at some live examinations. Here on the right we can see some peripheral examinations using a 28 diopter lens and the indirect ophthalmoscope. These dark spots represent laser photocoagulation scars from PAN retinal, or peripheral retinal photocoagulation. And you can see by looking in different quadrants, the patient we’re able to see, the peripheral retina. Here we can have a live video and you can see that reflections are a major problem. But as you move the lens back and forth, you can look at different areas of the retina. And just like using a flashlight in a dark room, you can look carefully at every single aspect of the retina making sure not to have skipped areas. This is a more typical examination where we’re really just focused where the image is sharp and ignoring those areas where the image is less sharp.
Here’s an example of slit lamp stereo microscopy using a 90 diopter lens. And here we see my left hand is rested on the forehead rest to stabilize my hand and place the lens at the proper working distance. My left hand, in this image, is on the joystick moving it back and forth and looking at the optic nerve as shown on the upper left-hand corner here. Again with the slit beam we can evaluate and appreciate the cup, the disc, the shape of the eye, and look at the image in three dimensions.
Here’s an example of scleral depression. You can depress directly on the surface of the eye or you can use a cotton tipped depressors I’m using here on the lid. I have the patient look down, I place the depressor and then I have the patient look up at the 12 o’clock position. And I’m describing that I see a retinal tear and I’m encouraging the patient that she’s looking in the correct direction. As you see, I’m moving in an axial pattern from 12 o’clock to 3 o’clock and then I’m switching hands to look at 4 o’clock and 5 o’clock. And often, if you tilt your head a little bit you can get a better view in difficult areas. This person is very, very cooperative. You just see, I asked her to put her chin up and here she’s looking down in the direction of the depressor so we can see the anterior part of the eye. I shift around the chair and I resume where I left off. I overlap at the 6 o’clock position and move around the eye to complete the examination. What would this look like?
Here’s an examination of scleral depression of the normal peripheral retina. Depressing through the eyelid onto the eye itself. And by indenting the eye with dynamic movement, a small flat that may be nearly flat will become raised. It will pop up as you do that. If you take a piece of paper and have a tear and you move it back and forth that tear will open up and reveal itself with depressed scleral examination. In this example here, this patient had a scleral buckle. This is a scleral buckle and there is peripheral laser retinopexy using laser during the surgery. And again, we can look at the peripheral retina to see whether or not new lesions are present.
So which lens to use? We’ve already discussed some of this and there are a number of different options. Slit lamp lenses range from 60 to 90 diopter and there is a direct digital wide field lens which gives you a very large field of view, 125 degrees, but it’s the most minimized view. The advantage of wider angle viewed lenses that you can cover more and make sure that you haven’t missed a lesion. And if you have a slightly smaller image, you can always use the slit lamp to use its magnification to look at things more carefully. Again, looking at subretinal fluid versus a choroidal neovascular membrane versus retinal edema and preretinal hemorrhage, can all be appreciated using the slit lamp. And the fact that the beam has narrowed gives you a better idea of the contour of the retina. As the diopter number increases, the field of view increases, but magnification decreases.
Similarly for the binocular indirect ophthalmoscope lens, in comparison. The 14 diopter lens gives the maximum magnification almost four times greater than life size. 20 diopter less, 28 diopter, even less and the 40 diopter even less. But it gives, again, the wider field of view. The choice is always between the magnification and the field of view for the anatomy or pathoanatomy you’re trying to identify. Again, as the dioptic power decreases, the view decreases and the magnification increases.
Anti-reflective coatings are really just a brilliant innovation that’s been around for many years. Coatings are very, very thin coatings designed to be one quarter the wavelength of natural white light. And in being in one quarter of the wavelength, as the reflection comes back it is doubled to one half the wavelength and it results in disruptive interference. Meaning, that the reflective aspect, it disappears. So there’s low reflections if the surface is coated, usually on both sides of the lens, in this case a double aspheric lens. And you can see the reflections are markedly diminished. These anti-reflective coatings are critical. Scrubbing with tissues that have silica, scratching the lens, all will diminish the coating. And when that coating is gone, you’ll have a very glarey and difficult view.
Similarly, taking care of your lenses is terribly important. Fingerprints, scratches, dust on your lens, all degrade your view. If you’re very good, as Dr. Gass was, as my mentor, he could look through anything. He could identify every single thing, no matter how dirty his lens was. But for me, a crystal clear lens really helps you identify the details of the eye, it’s really essential.
Here are the three lenses that I use. The 28 diopter lens, as previously noted, gives a good balance between a wide field of view and the ability to see through smaller pupil. The 90 diopter lens, similarly allows the view of small pupils and gives a wide enough view of the posterior pole with significant magnification to look at macular lesions. And a digital wild wide field that I want to look at very wide lenses, I can look at that as well. I also have a gonioscopy lens and other lenses for looking at the anterior segment when that’s needed.
Now here’s some common issues, which I won’t talk about at length. We talked about how small pupils are difficult. How cleaning is very important and it’s important to do it correctly. One of the tips was to clean your lenses in a clockwise direction. That’s because there’s a lens locking ring that if you go in a counterclockwise direction it actually loosens the lens within its holder. The directionality, it is not a symmetric lens and there is a proper direction to face the patient in a proper direction and a proper direction to face the observer. Glare can be managed by looking at the Perkinje images, the reflections on the surface. But essentially paying attention to what movements reduce glare and improve your view. High magnification is a very wonderful thing for seeing images, but even the smallest amount of movement will induce distortions and so a less magnified view generally is easier. And remember that this can be uncomfortable for patients. And that photophobia and blinking, don’t hold the eyelid open for extended periods, blink for the patient if you need to hold the eyelid there.
Lastly, I want to close with something, a project that I’ve been near to near and dear to my heart. But it goes to the crux of all learning. We want to learn what to look for. You want to know what pathology you are seeking or what you’re likely to find and chance favors the prepared mind. When we were interns or beginning our medical school, we were just full of questions to ask. And yet by the end of internship we really quickly calmed down, we looked at amazement at our attending, who would comb down with a few well-placed questions, got to the diagnosis seemingly out of air. Know what to look for. And to know that mastering this, even for me after 30 years, I can say I’ve never mastered it. But I’m better than I was and I continue to learn something every day.
This is a project that I started, it’s an educational platform that I started a number of years ago called the Retina Image Bank from the American Society of Retina Specialists. Here’s the website: ImageBank.ASRS.org. And in this, we actually have approximately 25,000 images with a commitment up to 60,000 images, including pathology, of all kinds of things retina. All things retina are here. If we type in “peripheral retina” which we want to look at, we can hit the Discover button. And if we do that we will come up with several hundred images of the peripheral retina. If you hover over one of these images, like I do here, you get a spot of magnification of this lesion here. And you can see this is a horseshoe tear. You know that because it says so right here.
In addition, you see that you’ve lost the markings of the choroid beneath it and so this is not only a retinal tear but a retinal detachment. If you further double click on it you will get a screen like this where you actually will get the author, the contributor, and the clinical description including keywords. This is an example of lattice degeneration with a retinal hole. And this is from Norm Buyers, the peripheral retina in profile, where he had an entire atlas of stereoscopic images. So if you are able to look at this image and cross your eyes, you can actually superimpose those images and you will see that three dimensions just like you would with a binocular indirect ophthalmoscope or if you use a stereoscopic viewer.
There are Untold number of peripheral examinations. This allows you to say what am I looking for and what facets of that do I need to look for in order to identify it during my exam? And you also may download these images. Now each one of them has an electronic watermark with the author and contributor. And I’d ask you only to respect the fact that colleagues all over the world have contributed their entire life collections for education. If you use an image, do it with proper attribution, all of these images are from the Retina Image Bank. The Image Bank is now the world’s largest, most comprehensive open-access resource for retinal Imaging. Anyone can access this. You do not have to be a retina specialist, you do not have to be an ophthalmologist, you just need to be interested in sharing knowledge around the world.
And since its inception a few years ago, we now have 2.5 million page views. We expect to go over three million this year, and it’s now used in 184 countries worldwide. It’s an invaluable resource for education and I hope that you use it and use it to educate yourself and your patients.
In summary, these are the five tips that I wanted to leave you with. It’s important to dilate the pupil. It’s a difficult examination, it’s one that’s critically important for the health of your patient. Practice and use perfect technique. All techniques can be learned, all techniques improve with time and with meticulous practice. Choose and care for your equipment. Your equipment is your stock-in-trade, take care and choose wisely for the right instrument for the right diagnosis. Know what you’re looking for. Educate yourself and learn for life.
I want to thank Orbis and Cybersight for this outstanding program. I congratulate my co-presenters on a wonderful session. We look forward to answering your questions. Thank you very much.
[Donny] Thank you, Suber, and thank you, Paul. Suber and Paul, how do you avoid the glare while doing 4 mirror gonioscopy or 90 diopter? Even with the anti-reflective coating that Suber talked about, you do get those glares and reflections. And so what are some of the tips for 90 diopters with Suber and for gonioscopy with Paul?
[Suber] Simply put, as with many physical things, the combination of tilt the lens and use the slit lamp beam to adjust so that you minimize glare. In many ways, it’s sort of a Gestalt after a while. You just learn what’s comfortable. Whether you’re hitting a tennis ball or walking or running or the best way to jump across a pond. You learn what your body is comfortable with. But just to pay attention about what makes things worse, what makes things better? But in general, if you move your beam off axis, if you pay attention to what is worsening, you tilt your hands with very small motions. Typically, you can at least eliminate glare in the area of Interest.
[Paul] I would agree. With a gonioscopic lens as well, tilting the lens to the specific part of the angle. Let’s say you’re looking at the nasal angles of the temporal part of the lens. Tilt your lens to that direction, moving the slit lamp in the off axis oblique position, that can allow yourself to decrease the glare. And then the size of the slit beam, adjust the size, keep it smaller and larger and that can help identify and decrease the chances of glare getting in your view.
[Donny] Yeah, great, great, great, thank you. It’s kind of like golf, people always ask where should I hit? Well, it depends on your speed. There’s a lot of Gestalt.
Question for Suber. Many people actually asked this question. Ideally it would be great to dilate everyone with full dilations, but as you know, especially when I go to Africa, with very dark brown eyes, full dilation is almost impossible. Even with atropine, I’ve actually noticed, any tips for looking at the peripheral retina using small pupils?
[Suber] It’s a good question. The answer is that you can get dilation in nearly everyone. We have many, many patients of African descent in the United States as well. And it’s a combination of using drops, I use tropicamide and 10% phenylephrine. I do a drop three times every second and I tell them they may not squeeze their eye and they may not have a tissue to wipe it out. That’s one tip. Atropine is actually a relatively poor dilator. It is long-lasting, but it is rather a poor dilator. And those two are ways to fully dilate the pupil.
But there are patients who have synechiae, as Dr. Singh alluded to. Many patients that have uveitis and so forth, or scarring where the people does not dilate. And in those patients, obviously the choice of lens, either a 90 diopter or the indirect using a 28 or 30 diopter lens helps you somewhat. But as a retina specialist, we are charged with examining the peripheral retina. And if you cannot visualize that through using your techniques and those lenses, then you have to say that those are areas of the retina that are poorly visualized. In areas where we are resource-rich, we use an ultrasound. We have to look at the peripheral retina to see if there is something there. In areas where we are resource-poor, we’ll do the best we can. And I think that is just the way of life, is that we do the best we can to see what we can see.
[Donny] That’s right, that’s right. And in some patients, some pediatric patients… I wish my patients were as cooperative as some of your patients, Suber. And you just have to try your best. I think I agree.
One other question is that in the retinal diagram, where do we mark the equator? What is the equator when you do the funduscopic examinations, Suber?
[Suber] The equator is the area where the largest circumference of the eye is. If you imagine a ping pong ball or a basketball, it’s the equator of the Earth where the circumference is the greatest. From a practical standpoint, you’d mark the equator roughly between the optic nerve and the periphery. So one part of the problem of that problem is that if you cannot identify the periphery then you’re just identifying a zone. The equator has no particular anatomic value. Typically the vortex veins are about the equator, if you can look beyond the vortex veins you’re in the mid periphery, and of course if you can see the aura, the pars plana, and the ciliary processes you’re in the far periphery.
[Donny] Thank you very much, everyone. And I look forward to seeing you at the future of Cybersight. Thank you for all your support.
[Paul] Thank you.
[Suber] Thank you.
[Donny] Take care.