Lecture: Clinical Examination of the Optic Nerve

This live webinar identifies the important features that define the glaucomatous optic nerve and outlines a systematic way to detect glaucoma progression on clinical examination.

Lecturer: Dr. Jody R. Piltz-Seymour, Clinical Professor, Perelman School of Medicine, University of Pennsylvania, USA


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DR PILTZ-SEYMOUR: Good day, everybody! It’s so nice to be here this afternoon. To share with you a little bit about examining optic discs. During the lecture, think if you have any questions, and jot them down and send them along, and we can answer them at the end of the talk. We’ll start with just a couple of questions, and please respond. And we’ll review these questions at the end of the talk as well. The purpose of today’s talk is to learn to identify the glaucomatous optic nerve and to detect progressive glaucomatous optic disc damage. So our first question is: All discs with a cup to disc ratio of 0.8 are glaucomatous? True or false? Okay. We’ll move on to the next question. Lawrence, my slides aren’t advancing. Let’s try this. Oh, there we go. Disc hemorrhages have no prognostic significance for Glaucoma. True or false? The most important characteristic to evaluate in the glaucomatous optic nerve is the color of the rim. True or false? Okay. And the last question: All of the following are signs of optic disc progression, except: Notching, the development of collaterals, vessel shifts, or nerve fiber layer swelling. All right. So I’m not gonna go over those now. Let’s talk a little bit about optic discs. Lawrence, I’m also trying to see how I can hide the stuff on my screen. All right. The purpose of today’s lecture is to try to figure out the most characteristic findings in the optic disc that will shout out to you that this is a glaucomatous optic disc. And then to see what we’re looking for, when we’re looking for changes over time, for optic disc progression. Glaucoma is a disease of the optic nerve. We think a lot about elevated pressure. We think a lot about visual field loss. But the actual damage is to the optic nerve. And the best place to look for that damage is by looking at the optic disc. So it’s nice to have fancy machines that do optic nerve head analysis or visual field — can check visual fields. But we always have ourselves, our patient, and hopefully a way to just look at the optic nerve, and if you can examine the optic nerve very carefully and closely, you’ll be able to find glaucoma in your patients, easily. What is normal? Most optic nerves are vertically oval, and they have rim tissue composed of ganglion cell axons, glial tissue, and blood vessels. Axons pass through the pores of the lamina cribrosa, as they exit the eye towards the brain. The optic nerve is vertically oval, and the most characteristic pattern — though this is not true for every optic disc — follows the ISNT rule. It says the thickest is the inferior rim, next thickest is the superior rim, then the nasal, and then the thinnest is the temporal rim. Most optic nerves have cup-to-disc ratios of less than 0.5. I think it’s important to look at the characteristics of the glaucomatous optic disc. And I have a mnemonic, SHIP, where we look at the size of the disc, whether it has hemorrhages, we look at the rim tissue by looking at the ISNT, and we look for parapapillary atrophy. OCT is excellent at looking at retinal nerve fiber layer. But there’s a lot you can see, especially in darkly pigmented eyes, just by looking directly at the discs. For me, one of the most important first steps is to judge the size of the optic disc. I’m not talking about the size of the cup. I’m talking about the actual size of the optic nerve. There is great variation in the size of the optic nerve. So that these two optic nerves… Are both normal optic nerves. We have a small optic nerve here. And we have a large optic nerve here. And you can see they look very, very different. Even though they are both normal optic nerves. Small optic nerves should have small cups. Large optic nerves can vary — normally have large cups. And that can be a completely healthy optic nerve, with a large cup. But a small optic nerve with a large cup is not normal. So there is great variation in the size of the optic nerves. Most people will have an average size optic nerve, by definition. But the variability is extensive. And you can see there can be five times’ difference in the size — in the outliers of the optic nerves. Nerve size. And the size of the cup of the eye is directly proportional to the size of the disc. And this has been repeated in numerous studies. And you can just see two of those plots here. So the larger the disc, the larger the cup can be and be normal. So if you don’t think about the size of the disc, when you start to examine them, you can really make some mistakes. You can miss the diagnosis of glaucoma in a small eye, and this is actually a very small optic nerve, and this is a glaucomatous optic nerve, that has had progressive changes. Used to have no cup. And now has a small central cup. So in a small disc, you can miss the diagnosis. And in a large disc, you can misdiagnose glaucoma. So you can label someone as glaucoma, who does not have glaucoma. Small optic disc — it’s very, very easy to miss early cupping. And even a very small cup may be significant. Sometimes the atrophy around the optic nerve may be the first finding. This is a patient who had very elevated pressures, into the 40s, and was lost to follow-up. Didn’t come back right away. And came back with a cup, a central cup. Where they had no cup before. And had a visual field defect. You can see there’s a central cup here, no cup before. No notching, which is concentric cupping, which is often characteristic of eyes that have very elevated pressures. And you can see that there’s this pigmented atrophy around the optic disc, that also wasn’t there before. So beta parapapillary atrophy is often an early finding that you can see in these small optic nerves that develop some cupping. And here you can see another relatively small optic nerve, with a somewhat generous size cup for the size of that disc. And this patient has nerve fiber layer loss that we can see. And then the flip side is that you can have large optic nerves, and some of these optic nerves can be normal. One thing to really watch out for is the asymmetric — a patient that has asymmetric disc sizes. This was a patient that was sent to me because the patient had asymmetric cupping. The doctor thought that there was asymmetric appearance in the cup of the optic nerve. And that is true. This eye definitely does have a larger cup than this eye. But this optic nerve is about a third larger than this optic nerve. So if you see asymmetric cupping, one of the first things to look for is asymmetric disc size. Well, how do you measure the optic disc? If you have an OCT machine, it prints it right on there for you. But in the office, with the patient, the easiest way is to use your direct ophthalmoscope. Most ophthalmoscopes have a 5-degree spot. In the newer Welsh-Allen ophthalmoscopes, it’s the center spot. If you take that and shine it in the back of the eye, most optic nerves will be just a little bit larger than that spot. It doesn’t sound intuitive, but the ophthalmoscope with the 5-degree spot will shine a circle of constant diameter on the retina, as long as the patient has refractive errors between + and -8. So you can use your ophthalmoscope as a measurement. The other thing you can do is use your fundus lens. Each of those lenses, the 90 or the 78 or the 60, you can use a vertical line from your slit. So if your slit beam has the ability to have a vertical… You can change the vertical height of the slit beam light, and actually measure the vertical diameter of the optic disc. There are different correction factors for the different lenses. For a 90-diopter lens, the optic nerve on average is 1.4 millimeters in vertical diameter. A large optic nerve would be 1.6 or greater. And a small would be 1.2 or less. So that’s size. So first thing, assess the size. Then I like to take my attention to the rim. Let’s see the thickness of the rim. To do that, you really have to outline where the disc is. In this eye, it’s pretty clear. Sometimes with parapapillary atrophy, it’s a little bit difficult. So we can see the edge of the disc is here. And then we look for the edge of the cup. Right around there. And I’m assuming everyone can see the arrow on my screen. And then we look for the thickness of the rim. So from here to here, inferiorly, here to here superiorly, here to here nasally, and here to here temporally. It has a thinner rim inferiorly than superiorly, so that’s okay. But this eye doesn’t follow the ISNT rule. You want to look for focal rim thinning, generalized rim thinning, and saucerization. That’s the gradual sloping of the rim. Different optic discs cup differently. And sometimes we can actually assign some pathologic mechanisms or some demographic findings associated with that. Different commonalities. Generalized cupping is a very common form of cupping. That’s when the optic disc enlarges, circumferentially. Not preferentially. So you don’t lose just one area, but you gradually use a bit of the rim tissue all the way around. It’s most commonly seen when patients have high intraocular pressures. When you have concentric loss, you can wind up having a normal visual field for quite some time. You can lose a lot of your optic disc tissue and still have a normal visual field. Because we have a lot of redundancy in our nervous system, you can lose a bit all the way around. Quite a bit. And still have normal visual function. This is in contrast to people that have focal loss. People that have focal loss lose a lot, all in one spot, or lose everything all in one spot. So they may have a much more robust nerve fiber layer or thicker rim everywhere else, but because they’ve lost one small area, they will have visual field defect earlier. So focal loss is when you see inferior thinning of the rim. I’m sorry. Just focal thinning of the rim. And it can be inferior or superior. Often more common inferiorly than superiorly, but it can happen either way. And this is where, if you’ve ever heard the term “vertical elongation of the cup”, this is where you have vertical elongation of the cup, because you have preferential loss inferiorly and superiorly. There’s some bending there as well. This is a bit of beta parapapillary atrophy. Let’s take a look at this disc. This looks like a beautiful disc. Nice. Here’s the edge of the disc. Here’s the edge of the rim. Everything looks quite nice. No real parapapillary atrophy. No nerve fiber layer loss. And now look six years later. What do we have here? Here is again the edge of the disc. But now the edge of the rim — superior rim looks okay, but there’s focal notching down there. This patient has focal loss. Lost the inferior rim. So focal loss may give you a form of glaucoma — some people refer to it as having an “acquired pit”. You’ll see visual field loss earlier. And very often these focal areas will be associated with a prior disc hemorrhage. A very common form, probably the most common form, of cupping is a combination. Some concentric loss, and some focal loss. And this is a patient that has a very enlarged cup. Rim loss all the way around, focal loss down below. And we’re getting ahead of ourselves a little bit, but you’ll see also beta parapapillary atrophy around that optic nerve. And here’s another example of progressive loss. So here the patient — edge of the disc. Edge of the rim. Let’s go all the way around here. So not a completely normal nerve. Has thin rim inferiorly, which should be our thinnest rim, but intact rim. You can see here the little striations. Beautiful nerve fiber layer up here. And now a number of years later… Notching down below. Thin — look at the distance from here to here now. Thinning of the rim here. Thinning of the rim up here. And all the way around. So concentric enlargement, the whole optic cup enlarged, but loss of the inferior rim. Now, one of the questions earlier was about color. Pallor is not the way that we approach glaucoma, most of the time. When you see pallor of an optic disc, the first thing you have to rule out is a non-glaucomatous cause. Does that mean that no glaucomatous optic disc gets pallor? No. You can get pallor in an optic disc from glaucoma, when they’ve had a prior very elevated pressure spike. So some patients that have very, very high pressures, even for a short period of time, won’t wind up with cupping. They’ll wind up with pallor. But you can’t always make that assumption. If you see pallor, you first have to think non-glaucomatous, and then rule out — rule in glaucoma later on. And this is an example of a patient that had a nice disc here, had episodes of elevated pressure, and wound up with pallor. It’s a little bit of… You’ll have to trust me a little bit on it. You can see that the exposure is a little bit different between the two photographs. But this patient did have pallor. And this is — this patient is a very good example. This is a patient I have followed now for over 25 years. Back in the ’80s, before I met him, he had these beautiful photographs with nice rim tissue in both eyes. Pink, nice pink tissue in both eyes, intact rim anatomy. And then he was a young person that had very, very high pressures. Pressures as high as 47. And when I met him, he looked like this. And what was really intriguing is that this eye cupped, and he had loss of his neuroretinal rim all the way around. And I will show you later — this is not rim tissue. This is the scleral insertion. So when you lose all of your rim tissue, you start to see the scleral insertion. So this patient has literally no rim tissue here. But his other eye didn’t cup so much, but became pale. I can’t explain it. And he stayed exactly like this for the last 25 years, and luckily has held on to a small 5-degree central island in both eyes. But here’s a patient where one eye decided to cup, and one eye decided to become pale with very high pressures. Another pattern of glaucomatous cupping is saucerization. So saucerization is when you look at an optic disc, and you say: That person has a 0.4 cup, and the next person looks at the optic disc and says that person has a 0.8 cup. And you’re both looking at the same optic nerve, and the reason you’re calling it differently is because the rim is not defined sharply. It is a gradual sloping of the rim. And sometimes the rim tissue that’s there is not robust. You can almost feel like you can see through it, and we sometimes refer to that as “moth eaten rim”. The rim just looks like something has eaten away at — it’s still there a little bit, but it’s not dense. So pale saucerization, moth eaten rim, and this is often associated with older patients who have atherosclerosis. It’s often very associated with beta parapapillary atrophy. So here’s the edge of the disc. And it’s hard to call it the edge of the rim. It just sort of slopes. But this is beta parapapillary atrophy around the optic disc. And it’s sometimes very difficult to see changes, because it’s just a gradual change in slope. It’s not a sharp edge of the rim that’s changing. Another type of optic disc to look for is the myopic tilted discs. These are congenitally anomalous discs. Usually associated with myopia. Often associated with high myopia. But can also be seen in moderate myopia. And they’re sometimes just very, very difficult to interpret. And some of them will have slight visual field defects. Just from the anomaly of the appearance of the… From the anatomy of the optic nerve. But when they do go on to develop glaucomatous loss, they often acquire their visual field defects right adjacent to fixation. Most people, when they get field loss, they spare the central points on the visual field. The central 5 or 10 degrees initially. And actually are more prone to have defects from, like, 10 to 30 degrees, but myopic tilted optic discs, their first defect is often juxtafoveal. Right near the fovea. And this is a patient with very advanced glaucomatous damage. There is excavation, so you lose the vessels. There’s so much cupping that it’s undermined, and the vessels are passing underneath and then just popping out where we can see them. So there’s excavation and then exposure of that scleral insertion that I talked about. You start to see: This is the sclera that inserts where the optic disc inserts. It’s normally covered with the rim tissue sitting on top of it, when the rim tissue goes away, you see that scleral insertion, and the important thing is not to mix that up for rim. This is not rim tissue over here. This is the scleral insertion. I’m sorry. This is out of focus. Here the patient that I followed for 25 years — this is the eye that cupped. Before it cupped, it had nice, thick rim. And you don’t really see the scleral insertion. But if you pull the rim tissue up, and look then underneath, you now see that scleral insertion. The rim ends here. And this is the scleral insertion, not rim tissue. So some people would look at this and say: Oh, that’s a 0.8 cup. Why does the patient have a 5-degree island of vision if they have a 0.8 cup? This is not. This is a 0.99 cup, and this is the scleral insertion. When you have an in-focus patient, as opposed to an out-of-focus slide, what you’ll see is there’s a little bit of dark color here, and then it goes white. Once it goes white, that is not rim tissue. That is the scleral insertion. Okay. So — so far we talked about the size. And we talk about the patterns of loss of the rim tissue. Now let’s talk about hemorrhages. Because hemorrhages are a big red flag for glaucoma progression. Here we can see a hemorrhage, but they’re not always that obvious. Disc hemorrhages are very specific for glaucoma damage. They can occur in other diseases, but most of the time they’re gonna be caused by glaucoma. Or someone that’s going to develop glaucoma in the future. We most often see them with a form of glaucoma — normal pressure glaucoma. Though anyone can get a disc hemorrhage. But it’s more common in people with lower pressures, people that have vasospastic disease, often seen in thin women. People with low blood pressure. People that are orthostatic. So it also has a bit of an associated clinical appearance to it. We most commonly see disc hemorrhages at the poles. A little bit more commonly inferiorly than superiorly. We can see them anywhere along the rim, but they’re most commonly at the two poles. They are transient. They’re usually gone within three months. So they can easily be multiple, and they can be recurrent. You can see them with posterior vitreous detachments. Systemic disease. Vascular occlusive disease. Anticoagulation. But if you see a disc hemorrhage, think glaucoma first, second, third, fourth, and fifth, before you think of other disorders. Disc hemorrhages are a big red flag for the risk of ongoing progression. It doesn’t mean everybody is gonna get progression. If you see it in a normal optic nerve, it doesn’t mean that everyone is going to develop glaucoma. But you really have to increase your surveillance, and really be concerned. Increased risk of rim loss and notching, increased risk of visual field progression, increased risk of retinal nerve fiber layer defects, and increased risk of parapapillary atrophy. In the large ocular hypertension treatment study, where we followed 2,000 patients over the course now of 20 years, seeing who goes on to develop glaucoma, what are their risk factors, and does treatment prevent or delay glaucoma, we also looked at the role of disc hemorrhages. And the risk of developing glaucoma was six times greater in ocular hypertensive’s eyes that had disc hemorrhages. And when looked at as an independent factor for glaucoma, there was a 3.7-times increase in the risk, compared from the baseline variables. When we looked at our 8-year data, 5.2% of eyes that did not have disc hemorrhages went on to develop glaucoma, while 13.6% of eyes with disc hemorrhages went on to develop glaucoma. Patients with disc hemorrhages were older. They had thinner corneas, and they had larger baseline cup-to-disc ratios. One of the most important findings, though, was that only 16% of disc hemorrhage that were seen on optic disc photographs were detected during the preceding dilated exam with the doctor. So that means that the doctors — and these are glaucoma specialists — missed the vast majority of disc hemorrhages when they did a dilated fundus examination. And that is why you have to spend a moment, when you examine every optic nerve, and say: Now I’m going to look for disc hemorrhages. And just spend that moment looking for disc hemorrhages. When you look at an optic nerve, vertical red lines look like blood vessels. If you just take a quick glance at an optic nerve, and your brain sees a little vertical red line, they’re gonna just say “blood vessel”. So you actually have to go around and say: Let me take a quick look. And make sure any linear red line I see is a blood vessel and not a disc hemorrhage. We saw this disc before. Nice, healthy-looking optic disc. We know this patient wound up having a focal notch in their inferior rim. And look, in the years in between, they had a — not subtle — a very obvious disc hemorrhage. So the disc hemorrhage never occurs in the base of the notch. Always occurs in rim tissue. So you never get — you don’t get disc hemorrhages where there is no rim tissue. But they will occur at the edge and will cause extension of that notch. Here’s a patient, going back a few years, with a slightly large disc. A large cup. But nice intact neuroretinal rim all over the place. Comes in here with a disc hemorrhage. And a few years later, we can see thinning in that area where the disc hemorrhage was, but there’s also thinning down here. You can see the rim has some thickness here. And now the rim is much thinner down here. So it was a marker of rim loss, locally. But if this patient has a disc hemorrhage here, they may very well have had disc hemorrhages elsewhere, or have a combined form with other factors, also increasing the cupping. So now let’s move on to parapapillary atrophy. This is this loss of elements, retinal and choroidal elements, around the optic nerve. And also we’re gonna look at that, as well as nerve fiber layer loss. So where a lot of us have gotten very spoiled over the last few years, with our OCTs, with our machines that we can see nerve fiber layer defects so prominently… But especially in patients that have a fairly darkly pigmented choroid, you can see them with photography, certainly, but even on examination, you look closely, and you look for this area that is darker, and where you can see blood vessels sharper. So the nerve fiber layer runs on the surface of the retina. On top of everything. On top of the blood vessels, and on top of the entire retina. And it’s very reflective. So that light is shown back. So if you lose — and also, the nerve fiber layer runs over the vessels, and kind of smudges their appearance, when you look in. It kind of blurs the edges of the blood vessels. If you lose the nerve fiber layer, the appearance of those blood vessels becomes sharper. So this doesn’t show up that great in this photograph, but when you look in person, you’ll see the blood vessels are sharper, and there’s a dark area, usually a nice — in a wedge — where the light is not reflecting back, because you’ve lost that nerve fiber layer. So here’s a patient that has loss of the inferior rim here. Has a wedge-shaped defect. With loss of nerve fibers in here. And I think here you can appreciate that we can see the blood vessels sharp, and when we look here, there’s sort of — it’s as if someone put a little bit of paint over the surface. Where they’re covered by nerve fiber layer. Here they’re a little bit more bare. And there’s beta parapapillary atrophy here. Here we have another optic disc. This patient was followed for many years. Has a focal notch down here. With loss of nerve fiber layer. And when we look here, it’s a little hard to judge here where the rim is, because of how the photograph was done. Maybe there’s some loss here. The focal notch looks the same. The superior rim looks just as healthy as it did back 25 years earlier, and the thickness of the nerve fiber layer defect, the width of this defect, is pretty much the same. I always try to look how close it is to the adjacent blood vessels. And it’s just about the same. And here’s another patient. Also a nice… Here’s the vertically oval disc. With intact rim down below. And intact rim up above. Vertically oval cup. Most likely completely normal here. And then here has some loss down below. And we can see that nerve fiber layer defect inferiorly. One thing to keep watch of here: Look at this blood vessel. It’s coming around the edge of the rim, and then coming down here. Now it’s falling into a hole and coming out. So blood vessels are very often a very good marker of where there is damage. So look for the path of the blood vessels. This one is clearly coming around some healthy rim, and now in that same area, it’s falling into a pit. So when we look for progression over time, we look for thinning of the rim. Widening of the notch. Hemorrhages. Shifts in vessels. Increase in beta-peripapillary atrophy, increase in pallor, and widening of nerve fiber layer defects. Most of what we’re gonna look for is up here. But these can also give wonderful clues. If you have access to a photograph, that’s so great to have in the chart. You don’t have to do them all the time, but get a baseline, and then when you look in, you can compare to that baseline. That’s wonderful if you have that. If not, I really believe very strongly in still doing detailed drawings. Here — this is that same patient we just looked at with the vessel shifts. We don’t have to go over it again. And the development of the nerve fiber layer defect over time. So again, changes over time. And this is a case of a patient that has increase in their beta parapapillary atrophy. So we can see the atrophy is just a little bit here. And look how extensive it is down below. Look at the vessel here, and now the vessel falls down into a bit of a hole over here. One thing that I didn’t go into great detail with is these little areas where blood vessels constrict, as they cross over the edge of the disc. That’s also — can have a prognostic implication for glaucoma. There’s also a greater risk of glaucoma change if you see little constrictions of the blood vessels as they cross the edge of the optic disc. So here we have — just to look for progression, we’ve seen this patient before. We have thinning of the rim. We have inferior notching. We have shifting of the vessels. And we have loss of the nerve fiber layer. This patient doesn’t have focal loss, because it’s so extensive. But all these striations that you see here, it’s the beautiful nerve fiber layer. And now there’s no nerve fiber layer here. And there’s dense parapapillary atrophy. In some darkly pigmented people, the parapapillary atrophy will pigment, like we see in this patient. This is another thing that you can sometimes find in glaucoma patients. And that is the development of collaterals. Now, usually we think of collaterals with central retinal vein occlusions or with tumors, but you can get collaterals just with glaucoma. And in this patient, we see progressive glaucoma, rim thinning, beta parapapillary atrophy, and vessel shifts, but more than just the vessel shifts. This vessel here has developed a collateral, and the vessel architecture is completely different. And this was a paper we wrote some years ago, which showed, over time, complete rearrangement of the vessel pattern in this patient with collateral development. Never had a central retinal vein occlusion. Never had a tumor. Let’s see if I can find this. Lawrence, is there a way I can hide… Do you see the bar up on the top of my screen?

>> Nope, that’s just on your side.

DR PILTZ-SEYMOUR: Oh, there it goes. Never mind. Sorry. If you have access to photography, it’s lovely to get stereo photography, and to compare them over time. And this is a patient that is actually relatively stable over years. You can look at photographs from different dates and compare them. But let’s now look at how we would approach a patient that comes in. Again, these are the things we want to look for. Size, disc hemorrhages, rim tissue and how robust it is in different places, parapapillary atrophy, and maybe even as a bonus retinal nerve fiber layer. So let’s look at these eyes. Let’s look at size. I’m gonna shine my light from my ophthalmoscope in, and the light covers the whole disc. So if it covers the whole disc, that disc is small. I bring it here, and that’s quite a bit larger than my spot of light, so that’s a large disc. Right off the bat, I know I have a small disc here and a large disc here. So the 5-degree spot of light on most ophthalmoscopes — the optic disc should be just a little bit bigger. And let’s look here. This is a patient sent in because of asymmetric cupping. That optic nerve is small. The spot of light covers it. And that optic nerve peeks out around the edge of that spot of light. So this patient has asymmetric size of their discs. And may not have glaucoma. So their asymmetric appearance to the cup may be related to the asymmetric disc size. Here we need to look for hemorrhages. Here’s a small hemorrhage in one eye. Here’s a small hemorrhage at the edge of the notch. With nerve fiber layer thinning next to it. Here we want to again look for rim tissue. Here we have robust rim all around. Nice healthy rim. And here we have that notch. And again, we have that disc hemorrhage in between. And parapapillary atrophy. So one thing I want to mention about parapapillary atrophy is that it is not specific for glaucoma, but the more extensive it is, if you see it 360 degrees, or if you see it on the nasal side, it’s much more characteristic of glaucoma. So the more extensive — particularly if it’s on the nasal side of the optic nerve. It’s hard to tell parapapillary atrophy from a temporal crescent. That’s why nasal changes are very characteristic of glaucoma. So let’s take a look at this patient. They come in. And the first thing we’re gonna look at: The size of the discs. So there is a slight asymmetry. This optic disc is a tiny bit bigger than this one, but just a little bit. Now let’s look at the rim. Sorry they’re a little bit small on my screen. So here’s the edge of the disc. And here’s the edge of the rim. So this patient has an inferior notch. So we’re looking now at the rim. And this patient has an inferior notch. There’s some beta parapapillary changes, and if I look carefully, I do not see any disc hemorrhages. Any time I look at a disc, I’m gonna take a moment and say: Now I’m gonna look for disc hemorrhages. So this eye is clearly glaucomatous. Inferior notch, beta parapapillary atrophy. This eye has a bit of a generous cup for a smallish optic nerve, average to small optic nerve. But no notching. Does violate the ISNT rule a little bit. The inferior rim is slightly thinner than the superior. This one is slightly suspicious for glaucoma. The fact that they have glaucoma in their other eye — this is most likely early glaucoma, with beta parapapillary atrophy, but it’s not definitive. Here, this optic nerve — let’s take a look. Here’s the edge of the disc. Here’s the edge of the rim. It’s an average-sized optic nerve. We’re missing the rim here. So there’s a notch. There’s a disc hemorrhage. There’s beta parapapillary atrophy. This eye has glaucoma. There’s the size of the disc. It’s average to a little bit big. And the other findings that we mentioned. Let’s take a look for change over time. Here’s an optic nerve. With a somewhat generous cup. But it’s normal to slightly large optic disc. And now over time we see thinning. Some generalized thinning, particularly inferiorly. And then more extensive notching inferiorly, and some loss of nerve fiber layer down below. So progressive optic nerve changes. So this is a patient — again, I’ve followed for 25 years. Came in with inferior notches, when I first met her. But nice tissue up here. What other findings? So of course she has a lot of drusen, which only started to cause her trouble after I followed her for 20 years. But what other finding is seen here? Now I’m gonna look for optic disc hemorrhages. Oh, here’s a hemorrhage. This is not a blood vessel. This is a hemorrhage. Very easy to miss as a blood vessel. It’s not… It’s just adjacent to the disc. That counts as a disc hemorrhage. And you can see that is not present here. But look what is present here now. Beta parapapillary atrophy. So perhaps a little thinning of that rim. I think so. And now beta parapapillary atrophy in the area where that disc hemorrhage was. So disc hemorrhages can be subtle. Let’s just take a look here. We’ve seen this one before. A not so subtle disc hemorrhage, and changes throughout the optic disc, as we’ve seen before. Progressive optic disc changes in this patient. So… When we look at this patient, we’ll look at the size of the optic nerve. Is it normal? Yes. Maybe even a little bit big. Not small. Is there a hemorrhage? Yes, there’s a hemorrhage. Is there thinning of the rim over time? Yes, there’s been thinning of the rim. Definitely inferiorly and superiorly. Is there parapapillary atrophy? No, no parapapillary atrophy. And are there some vessel shifts? Yes, the vessels have shifted over time. Now, without photography, it’s hard to document vessel shifts. But we should be able to know… Here, nice intact rim. And then on the subsequent one, there’s notching, and that would be a progressive change. So we’ve gone over a lot about looking at optic nerves. How to approach an optic nerve, to determine if that optic disc has glaucoma in it. And then how to look for changes over time, what things you’re looking for. So let’s go back to the original questions, and see how we do here. All discs with a cup-to-disc ratio of 0.8 are glaucomatous. True or false? Very good. So the answer is false, as the vast majority of you agreed with. You can have a very large optic disc, and it can have a cup-to-disc ratio of 0.8 and be normal. So if you see an optic disc with a cup-to-disc ratio of 0.8, you have to know if that’s a large disc or not. If it’s a large disc, it might be normal. It might not. You have to check. But you can have cup-to-disc ratios of 0.8, if it’s a large optic nerve. If it’s a small optic nerve, a cup-to-disc ratio of 0.8 is not normal. So you need to know always the size of the optic disc, in order to interpret the size of the cup. Disc hemorrhages have no prognostic significance for glaucoma. True or false? Beautiful. 100% got this one correct. Disc hemorrhages, remember, they’re a red flag for possible glaucoma progression. They are a negative — they are a poor prognostic indicator for glaucoma. Doesn’t mean everyone is gonna get damage. Doesn’t mean everyone is gonna have progression. But you have to be on the lookout when you see an optic disc with disc hemorrhages. Very good. The most important characteristic to evaluate in the glaucomatous optic nerve is the color of the rim. True or false? Very good, yes. So the color of the rim is important to look at, but it is one of the least important things to look at when evaluating an optic disc for glaucoma. You want to look at the rim tissue itself, and you want to look at the topography of the optic nerve. Where the rim tissue is, how thick it is, rather than the color. So color is not a good indicator. If you see pallor, you need to be on the lookout that you may have a non-glaucomatous cause. But you really want to look for changes in the rim thickness. And the surrounding parapapillary atrophy. So we want to look for the shape of the optic nerve, more than the color. All of the following are signs of optic disc progression in glaucoma, except for notching, collateral development, vessel shifts, and nerve fiber layer swelling. Beautiful, yes. We can see notching, we can see vessel shifts, we can see disc hemorrhages, we can see collaterals, we can see beta parapapillary atrophy, we can see little constrictions of the blood vessels as they cross the edge of the optic disc, but we don’t see nerve fiber layer swelling. Excellent. So now do we have questions?

>> So there’s about seven questions. If you want to stop sharing your screen, you can pull them up.


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DR PILTZ-SEYMOUR: I see stop video. I see new share. New share? Thank you.

>> There we go. So you can just open up the Q and A box.

DR PILTZ-SEYMOUR: Thank you. Here we go. So the first question is: So there’s a question about disc size. So the size of the optic disc is determined by the size of the scleral canal. So the eyeball is made up of a very firm sclera, which keeps our eyeball all together, and it’s very, very tough, as we know, which is good, because we like the contents of our eyeball to stay inside our eyeball. The problem is the nerve fibers that come from the ganglion cells need to get out of the eye, to get through the sclera. So there’s an opening in the back of the eye, called the scleral canal. And that’s where the lamina cribrosa covers that. So there’s a mesh in the back of that scleral canal that the nerve fibers pass through that mesh, and exit the eye, and go back into the brain. The size of that opening, the scleral canal, determines the size of the optic disc. So you have nerve fibers in the eye, and they go through an opening in the back of the eye. If it’s a small opening, you’re gonna have a small optic disc. And all those nerve fibers have to squish through that little opening, and you’re gonna have a tight little optic nerve. Small optic nerve and no empty space in the middle, where the cup is. So a small scleral canal is gonna give you a small disc. If you have a large opening in the back of the eye, a large scleral canal, all the nerve fibers can pass through. There’s plenty of room. They hang around and stick to the edges of that scleral insertion, scleral canal, and then there’s a large disc with a large cup. Because the cup is the empty space where there are no nerve fibers. So that’s the difference between having a large optic nerve and a small optic nerve. And why a large optic nerve normally should have a larger cup than a small optic nerve. So I hope that clarified that. Maybe I should go this way. So someone asked: How can I measure the cup-to-disc ratio at the slit lamp microscope? So you can measure the cup-to-disc ratio at the slit lamp with your handheld fundus lens. A 90-diopter lens, or any of the lenses, but there’s a conversion factor that’s specific for each of the lenses. So what you do is you shine your slit beam light through that lens, and you can dial the vertical height of the light in the slit lamp to match the vertical height of your optic disc. And when you do that, you can read off, in most slit lamps, it will tell you the height of that beam of light. And 1.4 is the average size — vertical size of the average disc. When you use a 90-diopter lens. If it’s greater than 1.6, it’s a large optic nerve. Less than 1.2, it’s a small optic nerve. So that’s how — and it’s different with the different lenses. I only know the numbers offhand for the 90-diopter lens. So that was… The next one. How do you differentiate optic atrophy from pallor? Emanating from IOP spikes, especially when IOP is measured normal? So you can only make an assumption that the pallor you’re seeing is from high pressures if you’ve seen the high pressure. So if someone comes in to you, and they have optic disc pallor, and they don’t have very elevated pressure, you can’t assume it’s from elevated pressures. So the only way you can make the assumption is by history, or by actually having seen the elevated pressures. Someone has asked: What is the mechanism of optic disc hemorrhages in glaucoma? And we really don’t know for sure. Some people think that it has to do with mechanical shearing, as the nerve fibers and other elements go through the lamina cribrosa. If there are some shearing forces, you can get a disc hemorrhage. Maybe there’s an autoimmune or an inflammatory component as well. But we just really don’t know. So the next question is: What is the difference between parapapillary atrophy and beta parapapillary atrophy, and does it matter for prognosis? So there are two kinds of parapapillary atrophy. There’s alpha and there’s beta. Alpha is just that irregular pigmentation that you can sometimes see around the edge of the disc. Whereas beta is usually sharp-walled, and you can see down through — you lose the retinal elements. You lose the choroidal elements. And it almost feels like you’re looking at sclera. Alpha atrophy, where you just see the changes in pigment, is not prognostically related to glaucoma. There’s no risk of glaucoma with alpha atrophy. But beta atrophy is highly correlated to glaucoma. But it’s not unique to glaucoma. You’ll see it in other optic neuropathies, and you also have to be careful to distinguish it from temporal crescents. And they look very, very similar or they look the same. So only if it’s progressive, if it’s extensive — you would never make a diagnosis of glaucoma just on the basis of parapapillary atrophy. But it can be helpful, and we see it develop as a progressive sign of glaucoma damage. The next question is: How do we differentiate a large myopic disc with a 0.8 cup and parapapillary atrophy from a glaucomatous disc? As myopia is associated with POAG, how do we diagnose the glaucoma? It’s difficult. One thing for sure is that glaucomatous optic discs get worse if they’re not treated. So sometimes you just have to monitor people and see if there’s any changes over time. If you really are not sure, and the patient has a normal visual field. And normal pressures. Very often, we just throw that — if we see a large myopic nerve, large disc with a large cup, we try to assess, if we can, how nice the nerve fibers look on the retina, the retinal nerve fiber layer, and then we just try to throw that risk factor in with a whole constellation of how that patient is doing. Do they have other risk factors? Is there a family history? All those things. Do they have thin corneas? So we just keep that, then, as a risk factor, until — unless we see progressive changes. And you can treat. You can still treat, if you have high risk. I’m not saying never treat that. You can treat it if the patient as a whole is deemed to have a high risk. So were all these images stereo? And can you make these evaluations with monofundus photos? Having stereo photographs is always great. But you can make a lot of decisions, you can see so much, even with monoscopic images. You can see notching. You can see shifts in vessels. So if you have access to any photography, even if it’s non-stereo, it is great to get images. So yeah, stereo images are wonderful. But if you have just monofundus images, grab them. They’re still really, really worthwhile. The next question is: Can I explain notching again? So notching is focal loss of the neuroretinal ridge. In the optic nerve, there’s preferential — in glaucoma — there’s preferential loss of the neuroretinal rim inferiorly and superiorly. As we talked about, you can lose neuroretinal rim, and get glaucoma in many different patterns. And one of the characteristic patterns is focal loss, where you lose a scoop of nerve tissue in one location. Most commonly, inferiorly. Next most commonly, superiorly. And you just lose the entire neuroretinal rim in that area, and that we call a notch. The next question is: How long do disc hemorrhages last? On average, we think they last about three months. So if you see a patient, and they have a disc hemorrhage, and you see them a week later and they have a disc hemorrhage, it’s still the same hemorrhage. So they are not having repeated hemorrhages, usually, in that period of time. Does the examining lens affect the size of the cup? So that’s a very good question. Now, I’m not an optics expert, but the different lenses do have different magnifications in depth and in width. So I know there’s a more technical term. Radially — in the different axes. So the different lenses will make things look more pronounced than another lens, but they don’t — they shouldn’t affect the actual size of the cup. They just might make it appear more obvious. But nothing should change the actual size of the cup. The depth and the appearance, the stereoptic appearance of the cup, yes, but not the actual size. So the next question is a complicated one. It’s: What is the speed of progression of disc changes in high eye pressure, like we might see with closed-angle glaucoma? Everyone’s different. So you can… And it all matters with that patient’s sensitivity to pressure, and that patient’s… Also probably vascular status. How prone are they to have ischemia happening from the high pressure, which can play a role, and why you also sometimes may see some pallor. So the speed really depends on how robust that patient’s optic nerve is. We all know we have patients that have high pressures. Pressures of 30. And never get glaucoma. They’ve got these tough optic nerves, these tough nerve fiber layers, and a very robust vascular system. And then we have other patients that have pressures of 20, 21. Normal corneal thicknesses. And they get progressive glaucoma. So just as we can’t say that there’s one uniform pattern with them, we can’t say there’s a uniform pattern of progression in people that have acute glaucoma. So the next question is: If we see a suspicious disc but the patient has normal fields and pressure, when do we call the patient back for review? If he has risk factors like family history of glaucoma, does that change the management? All risk factors influence your decision. So when we see a disc that we’re concerned about, and the patient has normal visual field, we want to look at what the type of cupping was. So if you have the concentric type of cupping, where you lose a little bit everywhere, and that keeps going bigger, again, you can lose over 50% of your optic disc, and still have a normal visual field. If you’re thinking that you have localized thinning and a normal visual field, then you might really be seeing an anomalous optic nerve. So it’s hard to say. But the question specifically was when do you call the patient back? And of course, it does depend on the other risk factors. If the pressure is normal, the fields are normal, you have some time. If the patient says: Everyone in my family has blinding glaucoma and lost their sight by the age of 50, I would see them back a little sooner. But if they have no family history, and everything is just suspicious, six months is reasonable. So if you have no photography, no OCT, and no visual field, when to refer? That’s what this lecture was really — not about when to refer, but how to see glaucoma without anything fancy. So if we have an ophthalmoscope, even if the only thing we have is a direct ophthalmoscope, we can see these optic nerves, and we can really get a feel for whether or not they’re worrisome. So if you see disc hemorrhages associated with the notch, if you see a large cup in a small optic disc, these are all reasons to refer. But you can see so much and make so much decisions about whether or not this is glaucoma with no fancy instruments. Just by looking at the optic nerve. The more you look at the optic nerve, the more you’ll see, and the more you’ll feel comfortable about whether or not to say this is a really… This is a glaucomatous optic nerve, or this is a high risk for glaucomatous optic nerve. And then you’ll feel more confident about when to refer. What is the most important aspect in assessment of glaucoma discussion in myopic patients? So myopic discs are tough. They’re tough. So in terms of assessment, it’s really how that optic disc is living in the whole rest of the patient. So it’s all the risk factors. So it’s how suspicious that disc looks. Now, myopic discs can be all over the place. You can have giant myopic optic discs and can have big cups. You can have these teeny little tilted optic discs that have the vessels coming out in a reverse pattern. So it’s really very difficult. You can look for asymmetry between the two eyes, in terms of if they have similar-looking anomalous discs. If one eye has a higher pressure and thinner rim. You can throw that into the mix. But you have to assess them given all their other risk factors. And again, change over time is always the hallmark of glaucoma. So the next question is: How do you diagnose glaucoma when the pale area is smaller than where the vessels are along the cup? How do you diagnose glaucoma when the pale area is smaller than where the vessels are along the cup? So I’m not sure I understand this question. The pale area meaning the cup itself? Whoever wrote that in, if you could just sort of write in again, and try to give me a little bit more info… Because I’m just not sure how to answer that. Is any of the instruments like GDX or OCT can be used for evaluation of myopic eyes, like tilted discs? So OCT can be used to assess the nerve fiber layer for changes over time in myopic discs. The normative database for the OCTs and the GDX do not include highly myopic tilted optic nerves. And the patterns for a highly myopic tilted optic nerve are so variable, I’m not sure there will ever be a true normative database, since it’s so variable. But if you have an OCT, you can follow the patient over time. And so you take an OCT. You say… I don’t know. This looks abnormal compared to age-matched controls. I don’t know if this patient has glaucoma. But that’s that patient’s baseline. And then you can follow that patient over time. Using their own initial OCT as the control. The next question is: How to notice the retinal nerve fiber layer early, and what about the rule of red-free filter on the direct ophthalmoscope? Excellent point. If there’s diffuse loss of retinal nerve fiber layer, it’s really hard to see. It really is very, very difficult to see. But if you can focal loss, those arcuate loss of retinal nerve fiber layer, you absolutely can see them on examination. Especially if people have a good bit of pigment. The red-free — on the filter, on the direct ophthalmoscope — is an excellent way of looking at the retinal nerve fiber layer. I’m so glad you brought that up. So yes, you can use the red-free light on the ophthalmoscope, and you can do that on the slit lamp as well. Next question is: Which is better? OCT or GDX? So OCT is much better. It’s much more accurate. And it just has many more layers of information than the GDX. So if you have an opportunity to have access to an OCT, jump at it. It’s great. The problem that we are seeing here in the States is that people are so reliant on the OCT now that they don’t look closely at the optic disc. And I worry about our residency training in the States. That residents aren’t spending the time to study the optic disc. So I can’t stress enough that the reason I decided for my first Cybersight talk to talk about the optic disc is because it’s so important. It is the hallmark of glaucoma. Optic nerve damage. Be able to look at the optic nerve. Is laser treatment indicated in glaucomatous optic disc hemorrhages? So I think the question is asking: If you see a patient who is otherwise stable, and they have an optic disc hemorrhage, do you advance their therapy with laser treatment? It all matters. So again, it matters what the other risk factors are. If the pressure is 10, and they have an optic disc hemorrhage, and they’ve been stable for the last 15 years, no. So again, the disc hemorrhage is definitely a marker. I need to be a little bit more concerned. But you have to put that in the context of the whole patient. Is it possible to have nasal shift of vessels in the absence of glaucoma? Hm. How significant is the nasal shift in making a diagnosis of glaucoma? So when I was being taught glaucoma, they used to talk about nasalization of the vessels. That the vessels shift to the nasal side of the optic disc. And the reason they do that is because you’re losing the rim tissue. So it’s all about rim tissue. So unless there was another reason for them to lose rim tissue, I don’t see why those vessels should be shifting. There can sometimes be a problem with the vasculature, so if they have a central retinal vein occlusion or branch vein occlusion, maybe there’s a problem with the vasculature and it looks different, maybe there are collaterals, but in order to shift, you have to lose the nasal rim tissue, and you can lose rim tissue from ischemia. So ischemic optic neuropathy, even from vein occlusion. You can lose some rim tissue, and they can shift. But if there’s nothing else going on, you’ve lost nasal rim, and the vessels have shifted over, you have to be certainly very concerned about glaucoma. Can you go over the nerve fiber layer loss with glaucoma again? So… The nerve fiber layer is the most superficial layer in the eye. On the retina. So when you think about the retina, light comes into the eye. Goes through all the layers of the retina. Hits the photoreceptors. The photoreceptors synapse, and then they synapse through the different layers, and then they hit the most superficial cellular layer in the retina, called the ganglion cell layer. Each ganglion cell sends out an axon. And that axon runs along the inside surface of the eye, as the most superficial layer of the retina. When you look in, the thing you’re looking at first are the nerve fiber layers. They run on the surface of the retina. And they run across the retina, and from each ganglion cell around the eye, and then they all converge and form the optic nerve and exit the eye. So at the optic nerve, if you have loss of the optic disc tissue, you lose the nerve fiber layer. You lose that axon as it goes back to the ganglion cell. There’s retrograde loss. And so if the optic disc is losing those axons, all over the place, you get generalized cupping, and you also get generalized loss of the nerve fiber layer. If at the optic nerve you lose a focal bit of the optic rim tissue, you will lose a focal arc of nerve fibers. I don’t have a picture here. But go back and look at a textbook on the pattern of the nerve fiber layer in the back of the eye. So if you have the optic nerve, the nerve fibers arc above the fovea and they arc below the fovea. So from the inferior rim, they arc below the fovea. At the superior rim, they arc above the fovea. If you lose tissue at the rim of the disc, you’ll lose this arc of the nerve fiber layer. So look at a textbook, at the pattern of nerve fiber layer in the eye, and you’ll see the patterns that you should see when you lose them focally. So I think the next question is: How often should you examine the fundus of a glaucoma patient each year? And it all matters. Everything in glaucoma matters on the individual patient. So if you have somebody that’s stable, twice a year is probably good. I tend to take — when I see every glaucoma patient, I take a quick look in the back of the eye. I’ll use my 90-diopter, or I have a SuperField lens, and I’ll look in the back of the eye, and the thing I’m looking for most are disc hemorrhages. So I take a quick look back there, see if there are some disc hemorrhages, and then usually about twice a year — I’ll dilate once or twice a year. But again, if you have a patient who has been stable for 20 years, maybe he’s a suspect, maybe has stable glaucoma for 20 years, I’m sure once a year fundoscopy is probably fine, if they have no complaints. If you have someone who is not stable, other concerns, high risk factors, you don’t know them well over the years, you probably want to do it more than once a year. And with your little fundus lens, you can always get a peek in there, even if they’re not dilated. Do localized nerve fiber defects follow the arcuate nerve pattern? Yes, exactly what I was trying to draw with my hands before. So if you lose a bit of nerve tissue, you lose the nerve fibers in that arcuate pattern. Exactly. So the next question is: Are there characteristic visual field changes in angle closure glaucoma? So I think… No. I mean, they tend to have the characteristics when you see high pressure. So you can have just generalized loss. And you’ll get arcuate patterns. Angle closure glaucoma is sometimes tough, because people can lose acuity. They get cataracts. They can have an element of ischemia. So that very, very high pressure can cause some ischemia, and that’s why you sometimes see the pallor. So it’s a little variable as to what their pattern is. But it all matters — how long the pressure is elevated and how extensive the damage was. So this is a question about: When the pale area is smaller than the actual cup. So again, color is not that important. So I think the most important thing, when you’re looking at the disc, is to know what the topography of the disc is. To know the physical structure. So it’s more about the shape than the color. So if the pale area is small, but the physical depth — width of the cup is larger — I would say go with the physical width. So it’s about the shape, more than the color. So yes, the actual cup size and how you would prognosticate from that would be based on the physical width of the cup. Not the color. So angio-OCT. I’m gonna say right now I don’t have enough experience with angio-OCT. This was the question: Does angio-OCT reveal glaucoma or progression? It’s very hard to know. I had a very strong interest in optic nerve head blood flow, years ago. Way before angio-OCT. And we know that there’s diminished blood flow in the optic nerve, and diminished blood flow in the retina, where glaucoma is. We don’t know which came first. Do we lose the blood flow in the optic disc, because there’s less nerve tissue there, so we don’t need the blood vessels? Or do we lose the nerve tissue because we lost the blood vessels? So I don’t think we have a good grasp on the chicken or the egg, which came first, the blood loss or the progression. So that still remains to be seen. I think it’s gonna be a very interesting area of research over the next few years, though. Next question is: An OCT which is credible in detecting retinal nerve fiber layer or GCC, and if we have a normal RFNL and GCC deficit, do we consider it like glaucoma? Let me read that one more time. If we have a normal retinal nerve fiber layer, but the GCC is abnormal, would we consider it glaucoma? I’m gonna take the question as that, and if I’m misinterpreting, please just write in again. So if you have an OCT, you can measure retinal nerve fiber layer throughout the — from the optic nerve. And then the machine looks at a circle around the optic nerve, and tells you about the thickness of the retinal nerve fiber layer around the optic nerve. That will detect most of glaucoma, but not all. Some people will have their earliest defects in the macular area, and that’s where the ganglion cell complex comes into play. So if you do a macular scan, and look particularly at the GCC, the ganglion cell complex, you will pick up some glaucoma that you may have missed on just the retinal nerve fiber layer scan. So a lot of offices say… Well, should I do the retinal nerve fiber layer? Or should I do the macula? And I don’t do a very cost effective thing, but I do both. All the time. On every patient. Because there will be some patients that have an abnormal ganglion cell complex, while having a normal retinal nerve fiber layer. Most glaucoma patients will have their retinal nerve fiber layer loss, but you will miss some. So yes, I like to do both. What really is a suspicious optic disc, and who is a glaucoma suspect? So I pretty much could talk ’til next week about this. A suspicious disc is anyone that you look at with the criteria we talked about today and say… Hm, it doesn’t look like a perfectly normal disc. Maybe it has a cup that’s a little bit bigger than I think it should be, for the size of the disc. Maybe it violates the ISNT rule and the inferior rim really looks like the thinner rim. There’s rim there, but it’s a thinner rim. That’s a suspicious disc. Or maybe they had a disc hemorrhage, but everything else looks fine. All of those things are suspicious. And you can just follow them as a glaucoma suspect. You don’t have to treat everyone. Except for acute glaucoma, glaucoma is a slow disease. You have some time, as long as the patient comes back, to make some decisions. The next question is the effect of optic disc tilting on OCT glaucoma assessment. So our normative database doesn’t have a lot of tilted optic nerves in it. So this is again a good situation where you get a baseline scan on that patient, and barring any other glaring things that that patient has, that says they definitely have glaucoma, you can get a baseline on that patient, and follow them from their own baseline. And that, I think, is the best thing to do, whenever you have these anomalous optic nerves. There are some myopic optic nerves that you are not going to be able to follow with OCT, though. Those are the ones that have huge areas of parapapillary atrophy. Or have mediate problems. But most — you can take a scan and use that baseline scan as the patient’s baseline. The patient’s own control. Why do collaterals occur? I don’t know. So there are many theories about why glaucoma develops. And we have the mechanical theory, where there’s compression of the lamina cribrosa. But there’s also a vascular theory, where there’s focal ischemia, or impaired autoregulation, and so we hypothesize that there probably is some focal ischemia or some impaired autoregulation happening, and the optic nerve is not getting the nutrition it wants, and it tries to grow new vessels. Those collaterals. Disc hemorrhage is very important, but what if it occurs in a patient on anticoagulants? A differential diagnosis. So absolutely right. So disc hemorrhages are a prognostic indicator that glaucoma may be getting worse, but they are not pathognomonic for glaucoma. You can see disc hemorrhages in other diseases, and you can absolutely see disc hemorrhages in anticoagulation. So you have to keep that in mind, that every disc hemorrhage is not glaucoma. But if you see one in a glaucoma patient or a glaucoma suspect, you need to be careful. But yes, anticoagulants can increase the risk of having disc hemorrhages. So you have to throw that into your risk analysis. For progression. Can glaucoma remain stable over ten years without any changes, or should we reconsider this case of the initial diagnosis? So it’s interesting. Most glaucoma will change over time. If left untreated. And if everything else about that patient stayed the same. Sometimes we don’t treat the glaucoma, but the doctor puts the patient on oral beta blockers for their hypertension, and in essence, they’re getting treated. But if you have a patient over ten years without any changes, you certainly become less worried. Now, glaucoma can occur gradually, or it can occur episodically, where they stay stable for long periods of time, and then have a dropoff. And then stay stable, and then have a dropoff. So it could be that. Ten years is a long time. The collaborative normotension glaucoma trial did find that many normotension glaucoma patients remained stable for many, many years without change over time. So one of their recommendations was in some of these patients to watch them before starting treatment. So have an element of suspicion. I will sometimes take people off medicine that other doctors had started medicine on, if I think they’re a low-risk suspect. In terms of being a suspect and being watched — some people like to be watched on treatment. Some people like to be watched off treatment. It always matters what their ratio is, of how much they want to avoid treatment and how much they want to avoid risk. So it’s a balance. Is disc hemorrhage always glaucoma, and is it always an indication for treatment? No, disc hemorrhage is not always glaucoma, and it’s not always a reason to start treatment. So it is just something you throw in the whole risk assessment catalog. So you just add it to your list of pros and cons. And that’s how I think of it with patients. I sometimes will make in their chart two columns. The preglaucoma and not glaucoma, and what the risks are. So this side will have a disc hemorrhage. This side will have thick corneas. So you just need to always evaluate the risk assessment. Is the laminar dot sign characteristic for normotension glaucoma? Not really. And it’s not necessarily just normal pressure glaucoma. As you lose nerve fibers, you may start to see the pores of the lamina cribrosa, and those are the laminar dots. You may see laminar dots any time you have glaucomatous loss, but it’s not specific for a type of glaucoma. And some people — normally you can see the laminar dots, particularly if they have a large optic nerve. So it’s one of the soft signs of glaucoma. I don’t usually bring it up, because it’s so variable. If you have a patient that you can never see laminar dots and then they come in and you can see a big inferior area of laminar dots, it’s probably because they have a big notch in that area. Is it always necessary to use refraction correction while doing the CVF? Is that a confrontational visual field test? When you do a visual field test, especially an automated visual field test, you absolutely want to use refractive correction. And you want to use near refractive correction. Specifically for whatever size bowl your visual field machine has. If it was for confrontational visual fields, then it’s a little bit less clear, because it’s so gross that they may or may not, depending on how bad their refractive error is. And also, if you’re testing peripheral visual field, you want to be careful not to have the rim of the lens blocking anything. So sometimes when we do peripheral field testing, on automated perimetry, there’s a point where you take the lens away, so you can test the more peripheral vision. The next question: I read in a book if the glaucoma patient is left without treatment, he will lose all of the vision in about 30 years. Is this true? Everyone’s trajectory is different. So when I see a patient, when I teach residents, I say to them: When you see a glaucoma patient, you want to know where they are on the spectrum of glaucoma. In the spectrum of glaucoma, meaning from absolutely no glaucoma to, like, early glaucoma, some glaucoma, visual field loss, all the way to complete blindness. You want to know where they are on that arc, and how fast it took them to get there. So if they’re early, and it took them 20 years to get there, you could probably not treat them, and they may do just fine. If they’re a younger person and they’re progressing rapidly, then they may go blind. So everybody is different. And everybody is on a different course. So it’s how extensive the glaucoma is and how quickly… How quickly it’s changing. So it’s the trajectory. The speed of the trajectory. If a patient’s best corrected visual acuity is less than 6/60, perhaps counting fingers, would confrontational visual field be reliable for the eye? So I think that CVF is not confrontational visual field that you’re asking me. So I think the question is: Would an automated test be reliable? If you have count fingers vision, you need to know why. If they have a tiny macular scar, you can still do a beautiful peripheral visual field. If they have count-fingers vision from end stage glaucoma, you’re not gonna get useful information from an automated visual field test. If they have mildly impaired vision, say 6/30, 6/60, you can always use a size 5 stimulus. The typical automated perimeter uses a size 3 stimulus. You can increase that to a size 5 stimulus. Sometimes even use a diamond target instead of a spot target for fixation, and you can still get reliable information. But if they’re count fingers from a glaucomatous cause already, you’re probably not gonna get very useful information. Next question. Is there more known nowadays about nutrition, alcohol, drugs, on the risk of glaucoma? Yes. But again, we don’t have great clinical trials. So in glaucoma, we don’t have a trial like the age-related macular degeneration study. So we can’t say: If you take these vitamins, we know we’re going to slow your progression of drusen in macular degeneration. We don’t have the same thing for glaucoma. But we do encourage… The eyes live in the body. And they are dependent on the nutrition of the body. And the nutrition of the blood vessels and the circulation. So we do encourage people to eat a healthy diet. There are some — especially Bob Rich in New York — strongly recommends certain supplements. Ginkgo. People have recommended resveratrol. There are some studies looking at nitric oxide-rich foods. Broccoli and some of the greens, for instance, as being beneficial as well. So I think we’re gonna learn a lot more over the years with that as well. Should we trust OCT results, especially when the disc exam appears normal, without any signs of glaucoma? Sometimes OCT shows a little bit of defects inferiorly, in patients with a normal disc exam. So if everything looks perfect to you on exam, the patient is at really low risk for glaucoma, and you see something funny on the OCT, not everybody is average. Some people will have little discrepancies and don’t follow the exact pattern. This is particularly common, as I mentioned, in myopes. They can have shifting of their nerve fiber layer humps. So we have these humps on the nerve fiber layer, inferiorly and superiorly. And in the OCT, you’ll have a map of the thickness of the nerve fiber layer in the ring around the optic nerve. And it can be different in some people. So I would just say watch the person over time. If you see a pattern where everything else looks normal and you get something funny on the O*BT, and you get something funny on the OCT, just continue to watch them. And last but not least: If an OCT result shows a mild defect in one of the rims but the overall TSNIT graph is still normal, is it an indication to start treatment? So yes. So not necessarily yes start treatment. But you can have an abnormality that is not seen in the TSNIT graph. So if you have… And I like to look — for instance on the Cirrus OCT, you can look on the entire cube. It will show you the TSNIT graph, which is just the ring around the optic nerve, but it will also show you a map of the thickness of the nerve fiber layer around the fundus. And if you see an arc of loss coming down, it may indicate early glaucoma. Again, whether or not you start treatment depends on everything else about the patient. Their risk factors, their pressures, their age, their underlying diseases. But you can have focal defects and generalized loss when the TSNIT map is normal. And something else I want to mention here: You can have what is called “green disease”. That is, you can have change over time and still have a normal TSNIT map. So if you have a very normal, very thick nerve fiber layer, you can go to just an average nerve fiber layer, and it can all be green. It can all be normal. But you have lost from a really excellent nerve fiber layer to just average. So people can have progressive loss, and still look normal on the OCT. I have a dog here. And he’s started to growl. The fundus exam for the patient in question — you just answered. Thinning on one of the rims. It’s very hard for me to put this together without seeing the picture. And if there’s any way through Lawrence to send me a picture, even through email, I’m happy to look at it. But when you see focal loss, that’s specific and in the shape and pattern that you would expect for glaucoma, then you have to say that this may be a glaucomatous nerve fiber layer defect. Okay!

>> Thank you so much, Dr. Piltz!

DR PILTZ-SEYMOUR: It’s been a pleasure, and if there are any other issues that develop over time, or people have questions, I don’t know what the protocol is, Lawrence, but people can feel free to email or send me messages.

>> Definitely. I’ll let them know. Thank you so much.

DR PILTZ-SEYMOUR: Thank you very much, everybody. Have a great day or night.

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February 2, 2018

Last Updated: October 31, 2022

4 thoughts on “Lecture: Clinical Examination of the Optic Nerve”

  1. It is very helpful to have more than one iop at different times of day before starting therapy. Because of diurnal variability, I try to have at least one early am and one later PM iop.

  2. Thank you for the lecture Dr. Jody R. Piltz-Seymour. It was very helpful. Can you please tell us about how to determine baseline IOP, how diurnal and nocturnal IOP fluctuation affects determination of IOP. Can we determine baseline IOP by very first IOP measurement. or at least how many follow up visits needed?


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