Lecture: Optic Neuropathy Part II: Ischemic, Compressive, Hereditary
This lecture covers presenting symptoms and signs of ischemic, compressive and hereditary optic neuropathies. Specific entities will include non-arteritic anterior ischemic optic neuropathy, giant cell arteritis, hypoperfusion, dominant optic atrophy and Leber Hereditary optic neuropathy.
Lecturer: Dr. Karl Golnik
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Greetings. This is Dr. Karl Golnik, speaking to you from the University of Cincinnati, in the United States. Good morning from the United States. This is our second Orbis webinar concerning optic neuropathy. So last month, we talked about inflammatory and infectious optic neuropathies, and that webinar was recorded and should be on Cybersight for you to review, if you wish. Thanks to many of you who submitted questions in advance of this webinar. I have looked at the questions and have pulled out the ones that are relevant to the topics that we’re gonna cover today. There were some questions relevant to the webinar last month, so I would ask you to look at that webinar, and certainly we can try to answer the questions, if you still have them, but some of the questions were explained last month. Additionally, there were some questions regarding specific patients. The best way to probably deal with those questions is for you to use the Cybersight consultation feature. So anybody can go to Cybersight and post cases, and have them directed to the relevant subspecialist, to try to get help with those cases. So I would advise for specific patients those sorts of questions. You will be able to ask questions, type in questions, during the course of this webinar, and we will try to handle all of those questions at the end of the webinar. So today we’re gonna talk about part II of optic neuropathy, more types of optic neuro problems. Ischemic, compressive, and hereditary. And I might throw in a couple of toxic and nutritional to boot. So my objective for this webinar is that when we’re done, you’ll be able to differentiate different forms of ischemic optic neuropathy, you’ll be able to identify presenting signs and symptoms of compressive optic neuropathy, and you’ll be able to describe at least two forms of hereditary optic neuropathy. So the differential diagnosis is complicated, and I don’t want you to read everything on this slide, but last time, as I mentioned, we talked about inflammation, infection, and so this time we’re gonna concentrate on the ischemic, hereditary, compressive, and talk a little bit about some miscellaneous causes. I’m gonna start with this case. A 68-year-old gentleman. Complained of blurred vision in the right eye, for the past week. It was fairly sudden and painless in onset. His vision is 20/60 or 6/18 in the right eye, normal in the left, and he has a right relative afferent pupillary defect. And so my question for you, given that scenario, given the appearance of those optic nerves, maybe I’ll scoot back to that for just one second — is to ask you what you think is going on, by asking this question. And I believe the host at Orbis will allow this question to be asked, although I’m not entirely sure how that’s gonna work. And the question is: What is the most likely diagnosis? Is it… Do you think this is ischemic, compressive, nutritional, hereditary, or inflammatory? So my understanding is we’re trying something a little bit different. I’m not the one running the show with this question. That said, I don’t see the question popping up anywhere or answers, so I will let the host… Let’s see. I’ll let the host run the he the show. So there’s the poll. Basically you click on the… I believe you just click in the box that you think is the correct answer. I hope. So if you think it’s ischemic, click in that box. Click in the box outside there. And I’ll let the host, Orbis host, decide when we stop. I think we have in the order of 100 people here that could potentially answer, but I think we can probably close the polling now and see if the results can be broadcast. Okay, so very good. Thank you. So the most likely diagnosis for most of you is the correct diagnosis. Ischemic. A few people thought maybe compressive, maybe nutritional, maybe inflammatory, but the vast majority said this is most likely ischemic. And that is true. Certainly in an older person, and I joke that every year, the definition of old changes. Last year, old was greater than 55. This year it’s greater than 56, because that’s how old I am. Next year it’ll be greater than 57. But someone over 50, let’s say, with sudden onset of change in vision, in one eye. Who has optic disc swelling — usually are going to have an anterior ischemic optic neuropathy. And the A just means anterior. There has to be disc swelling. So you can’t make this diagnosis in a patient who has no disc swelling. One of my residents just the other day said: I’m seeing this patient. They’ve lost vision in one eye. There’s no swelling of the nerve. Maybe this is an anterior ischemic optic neuropathy. I said by definition it can’t be an AION. But we think these are blood supply problems, there may be diffuse, even hyperemic swelling of the disc, like you see in the photo on the left, or there may be sectoral disc swelling. It may be pallid or pale, as you see in the superior portion of the optic disc on the right. And usually the main question is: Is this non-arteritic, by far the most common scenario, NAION. The same risk factors are for heart attack and stroke, in a sense. Age, hypertension, diabetes, hypercholesterolemia — does the person have the disc at risk? So in the bottom left pair of optic discs, you see our patient that I just presented, and in that left optic disc, meaning the patient’s left optic disc, there is no swelling. But there’s no cup. This is a disc at risk. A small, congested-looking optic nerve. It’s normal, but it’s small. Contrary to that are the two discs on the bottom right. One of the discs, the left optic disc of the patient, has mild swelling. They have some cotton-wool spots or nerve fiber layer infarcts in the retina. On the left, their left disc. Their right disc is normal, with a big cup. This is a big physiologic cup. This is not the disc at risk. So if you’re thinking non-arteritic ischemic optic neuropathy, and you look at the discs and there are big cups, think again. It’s not an NAION. Fairly recently, sleep apnea has been a risk factor, identified in NAION. I usually ask people about snoring. If they don’t snore, they don’t have sleep apnea. If they do snore, they may have sleep apnea. And depending on the patient, we may order sleep studies. Nocturnal hypotension might be a trigger of NAION. In the early morning waking hours, if you sleep normally, you have the lowest blood pressure of the day, and it’s thought that this low blood pressure is the trigger for NAION, which is thought to possibly be a compartment syndrome. Not just hardening of the arteries, but there’s something about this tight space in this disc at risk. And that low blood pressure in the early morning waking hours is the actual straw that breaks the camel’s back, the trigger. And so if people are taking blood pressure medications, I ask them not to take them at night, because that can accentuate the low blood pressure in the early morning sleeping hours. We don’t think this is related to carotid artery stenosis. This is not a big blood vessel disease. There have been studies that look at age and disease-matched controls. There’s no increase in the degree of carotid artery stenosis. I do not order carotid Doppler studies in this condition. We know from a study done some years ago, called the ischemic optic neuropathy decompression trial, a study that came about because there were some anecdotal reports that maybe optic nerve sheath fenestration is a treatment for this condition. So a study was done across the United States, where 200 patients were enrolled. 100 randomly got the surgery. 100 randomly got the gold standard, nothing. The hundred people that got nothing did better than the hundred that got the surgery, so we don’t do surgery. From that study, we then followed the 100 patients who got nothing, and found that over the following 6 months, about half had no change in their vision, forever. About 40% had some improvement. That does not mean back to normal. It means three lines or more. Somebody who’s counting fingers — three lines may be like no improvement whatsoever. So that does not mean back to normal, by any means. And 7% worsened, so the so-called progressive NAION. These 7% usually worsened in the first week, two weeks. At most the first three weeks. If that person can make it past the first couple few weeks, it’s very unlikely they’re going to have worsening vision from NAION. We also know from that same study that when they followed these patients for five years, followed them for five years, about 15% had the same thing happen in the other eye. And I often tell patients, after I tell them we have no proven treatment, I often tell them — the worst thing I’m going to tell you is that all of those risk factors we just talked about are the same for your other eye. So the risk — what’s the risk? And the risk is about 15%. About 15 out of 100 were gonna have a similar problem in the other eye. Now, I had a couple of questions here, about NAION, from before the webinar. One of them was that IOP elevations, intraocular pressure elevations, have been associated with NAION. I don’t think that’s necessarily the case. I don’t think there’s a study that shows that high pressure is a factor. We do think that high pressure could decrease perfusion of the disc. Certainly if they have high pressure, I would lower their eye pressures. I would not lower eye pressures in patients with normal eye pressures. And how do you manage incipient ischemic optic neuropathy? Incipient means very mild, the patient might even be asymptomatic. And the answer is there is no treatment for NAION that’s been proven. Seven years ago there was an article published by Dr. Hayreh in Experimental Ophthalmology, a retrospective study, where he looked at more than 600 patients with NAION. The practice had been to offer oral corticosteroids to patients with NAION. Some people took them. Some people didn’t. So he called the study design patient-choice. He found that overall, when looking at these patients, all very retrospectively, for 40 years, that there was no improvement, no change, or no difference in the two groups. He then looked at subgroups of patients defined as poor vision presentation, 20/70 or worse, versus good vision. There was no difference in the good vision group. But in the 20/70 group, there was, in his study, retrospective, there was better visual outcome in the group that got the oral corticosteroids. I would encourage you to read the article. If you Google Hayreh and Graefe’s Experimental Ophthalmology and NAION, I’m sure you’ll find the article. My practice is if acuity or visual presentation, is 20/60 or better, I don’t talk about the paper. If it’s 20/70 or worse, I mention it and offer corticosteroids at that point. I have not had anything that was a great success, and probably at some point, unless there’s further evidence, I will stop offering the corticosteroids. There was also one question, before I get to arteritic, and that was: What about evolving NAION? Will you treat or observe? I will observe. As I said, I don’t believe there’s a proven treatment for NAION. They’re looking at things like intravitreal Avastin and other medications, but at this point, I don’t think anything has been proven to be of help. So what about non-arteritic? And depending on where you live, this giant cell arteritis or temporal arteritis may not be something you see frequently. If you don’t see it at all, it may be because you’re not looking. Certainly I see it, but probably for every 100 patients I see with AION, for every 100, 95 have NAION, and 5 have AION. Arteritic. If there’s optic disc swelling, you need to think about it. If there’s white color of the disc. Because in giant cell, the mechanism is different. There is no blood getting to the nerve. So it’s unusual to see hemorrhages. It’s unusual to see hyperemic swelling. It’s usually going to be pale, there may be cotton-wool spots or infarcts in the retina. Those are all signs of giant cell arteritis. The most specific symptom that patients with giant cell arteritis have is jaw claudication. That’s either pain or weakness with chewing. It’s not pain with the first bite, but it’s pain when they use the muscles of mastication, or weakness. It can just be trouble chewing. So you have to be sure. They say there’s no pain. You must ask about weakness as well. They often but not always will have scalp tenderness. A new form of headache is very suspicious in someone over the age of 60. Fatigue, malaise, just feeling generally bad. This is a condition that’s unusual in the 50s. More common over 60 and then more common as you get older, 60, 70, 80, and so on. We usually check blood tests, depending on our level of suspicion. It’s easy to get the blood test. A sedimentation rate, a C-reactive protein, a CBC, complete blood count, with elevated platelets, are thought to be a marker. If we have high level of suspicion, we get the blood test, we start steroids, while we’re waiting for the blood test. Get the blood test right before you get the… Get the blood test before you start the steroids, but start the steroids and get a temporal artery biopsy. I never treat patients — or virtually never treat patients for giant cell arteritis without a temporal artery biopsy. So we want to get that biopsy done within the first couple of weeks, because of course the whole point of the steroids is to make the biopsy normal. Get rid of inflammation in the blood vessel walls. So you want to get the biopsy within the first couple of weeks and you want to get a couple centimeters of the artery. There have been reports of skip lesions, where a small section of artery is obtained. There’s no inflammation. But right next to that is inflammation. So you want to get a lengthy section, and look at a number of sections. Hundreds of sections, through the artery, to show that there either is or is not inflammation. So think about temporal arteritis. Again, depending on where you live, this may be more or less common. Now, there are some other reported causes and associations of anterior ischemic optic neuropathy. One is with these PDE-5 inhibitors like Viagra, sildenafil, and its relatives. The data on this now is thought to be — there is probably an association, in patients who present with unilateral — in men with unilateral NAION. They have the disc at risk. I do talk about the potential risk of taking this type of medication. And affecting their other eye. There’s already a 15% chance of their other eye involvement. So we talk about the data that’s out there, regarding the association between the PDE-5 inhibitors and NAION. There’s also been reports of amiodarone-associated optic neuropathy. I think this is probably real. The half-life of amiodarone is very long. 100 days. We usually recommend stopping the amiodarone in patients who come with optic disc swelling. The optic disc swelling may be unilateral or bilateral. Usually in my experience, the vision loss is not severe. I often call the cardiologist or the family doctor, depending on who started the amiodarone. I don’t like to stop other doctors’ medications without checking. And it’s unusual. To me, I usually get one of two responses. One, they’ll die if you stop their amiodarone. There is no other medication for them. In which case we continue the amiodarone. On the other hand, the most common response I get is — yeah, go ahead and stop it. And they don’t even want to start another drug. Why are they on it to begin with, if they don’t need it? But the most common response is: Yeah, just stop it. Let’s see what happens. So that’s the amiodarone story. There’s been one publication, back more than 13 years ago, where they even — where they tried to differentiate amiodarone-induced optic neuropathy from non-arteritic anterior ischemic optic neuropathy. In general, the vision loss isn’t quite as bad. The disc swelling can last for months and months. Again, the amiodarone is 100 days. And it’s often bilateral. Those are some of the main differences. These are some of the other names for amiodarone. Cordon, Pacerone. Here’s a patient. I’m not sure if the little box with my picture is in your way. It’s in my way. Oh, that’s better. Here’s a patient who presents, and I can tell you they’ve lost vision in this eye. I’m showing you the fundus. The other fundus looks exactly like this fundus. And there’s been a sudden change in vision in this patient. And this is someone who is elderly, I think in their 60s, which I guess counts as elderly by my definition, and the history was very much that of posterior ischemic optic neuropathy. So posterior ischemic optic neuropathy is rather rare. It’s much different than non-arteritic anterior ischemic optic neuropathy. So in a sense, non-arteritic, it’s idiopathic. We know the risk factors are there, but it’s very rare to make a diagnosis — or should be very rare — to make a diagnosis of PION in someone who just is older with blood pressure and diabetes. And I would advise you to be extremely careful about that diagnosis. In my 27 years as a neuro-ophthalmologist, I’ve probably made that diagnosis once in someone who was just a typical patient with no other factors. Just high blood pressure, cholesterol, diabetes, and they had multiple problems with blood vessels in the past. By far the most common reason that I see true posterior ischemic optic neuropathy — posterior meaning there is no disc swelling. It’s a retrobulbar form of optic neuropathy. It’s sudden in onset. Usually the most common times I see it are when the blood pressure bottoms out. In dialysis patients, sometimes their blood pressure bottoms out and they lose vision. After lots of blood loss from injury, from surgery, their blood pressure and their — they get very anemic. So you see it after surgical procedures, where there’s a lot of blood loss, or after resuscitation, where there’s cardiac arrest. I’m going to usually image these patients, even if I think it’s ischemic, because I’ve been fooled in the past. Of course, the patient might say it was sudden. I’ve seen tumors present this way, when the patient just suddenly noticed their vision was bad. Not when they actually had true sudden loss of vision. So I’m gonna image them. If I see a retrobulbar optic neuropathy of any kind, they’re gonna get in my clinic an MRI. At minimum, if you don’t have MRI, a CT. So beware of the diagnosis of posterior ischemic optic neuropathy, outside of the circumstances that I just mentioned. Dialysis, low blood pressure, lots of blood loss, cardiac arrest, where their brain and nerves are not getting the right perfusion. I had a question that was submitted prior to the webinar, and the question was: Differentiating PION from functional visual loss, acutely. Will there be a relative afferent pupillary defect? Certainly in functional vision loss — and I prefer the term non-organic vision loss, sometimes used — faking, malingering, functional — but in non-organic vision loss, of course there will be no relative afferent pupillary defect. In the setting of posterior ischemic optic neuropathy, if it’s unilateral or if it’s asymmetric, there will always be a relative afferent pupillary defect. If it’s unilateral or if it’s asymmetric. Just like any optic neuropathy that’s unilateral or asymmetric, there is going to be relative afferent pupillary defect. So to say just a little bit more about perioperative visual loss, because this is something we see, this is something that clearly generates lawsuits, and I’m an expert witness every so often for this type of a problem. Here’s a 41-year-old gentleman, had a motor vehicle accident. He had a back injury. Prolonged surgery to relieve spinal cord compression, he woke up, and he couldn’t see. He was NLP OU. His pupils were amaurotic, which means he didn’t react to light. Otherwise normal. He had a bilateral symmetric complete optic neuropathy. So neither pupil reacted. He had bilateral posterior ischemic optic neuropathy, because during the surgery, which was prolonged, he lost a lot of blood, they had to resuscitate him once, because his heart stopped, and he had unfortunately permanent bilateral vision loss from bilateral PION. Here’s another patient. A young guy. Who had low back surgery. Uncomplicated, but it took 9 hours. He did not have to be resuscitated. They kept his blood pressure on purpose this the low range. And he tended to run a higher blood pressure in his usual state. He did require some transfusion with red blood cells, and he woke up with 20/20 vision, but a change in vision, in his left eye, and a left relative afferent pupillary defect, with this inferior field defect and superior optic disc swelling, looking very much like a non-arteritic anterior ischemic optic neuropathy. Of course, in a 26-year-old, we typically would not consider the diagnosis, but he had undergone a 9-hour surgery with lots of blood loss, and relatively low blood pressure. So we think that this is a form of anterior ischemic optic neuropathy, related to perfusion problems of his optic nerve. And we know that when you look at vision loss after surgical procedures, ischemic optic neuropathy is most common. The anesthesiologists are very interested in this condition, because they get sued because of it. Unfortunately, it can often be bilateral and permanent. And, again, result in these medicolegal issues. There have been some studies that look at case controlled perioperative visual loss. This is an older study that looked only at spine procedures, and again, found predominantly ischemic optic neuropathy as causing the vision loss. Interestingly, when they looked at case controlled studies, there were no differences in the hematocrit, that is, the level of anemia, or the blood pressure. There’s something about these patients — when you talk to neurosurgeons, they say — we do these cases all the time. People lose blood, they have low blood pressure, but only a very small number have loss of vision. Why those patients? And the answer is we don’t know for sure. Probably something about their anatomy. Maybe it has to do with collateral blood supply. We just don’t know. There’s a lot of proposed factors, including hypotension, blood loss, anemia, hypoxia, the duration of the surgery, hemodilution, et cetera. You can read this list of potential issues. We don’t think that ocular compression really is a risk factor for optic neuropathy, but if you see a central retinal artery occlusion following surgery, it’s probably because there has been pressure on the globe. So there is a practice advisory for perioperative visual loss that is generated by the anesthesiologist. And that is that we don’t know for sure why these people get it. Likely there are multiple factors. But there is a high risk patient, quote-unquote, who has prolonged prone spine surgery, plus or minus substantial blood loss. So be careful. At least in the US, anesthesiologists now consent patients, when they have them sign the operative consent, for possible but unlikely visual loss after prolonged back surgery. All right. So I’m gonna move on now to another case. And this is a patient — not the best fundus photograph. I apologize. But a patient with… I’m gonna try to move this thing over here. I don’t know if… I can see this little box that’s hiding my slides. Maybe I can do that. There we go. And you can see hopefully… Again, I apologize for the quality of the slide… There is, I will tell you, some disc swelling. This is a relatively young person, 37, a male, who’s had mild blurriness. But interestingly, other than the blurriness that’s mild, they note vision loss in their left eye when they look over to the left. So if they look to the left for more than a few seconds, their vision gets blurry and dim. And they have this mild disc swelling, vision in the right eye is very good, at 20/15 and 20/20 or 6/6 in the left eye. They see all the color plates with the right eye, but miss half of them or so with the left. And there is a left relative afferent pupillary defect. So this has been going on for some time. At least weeks, maybe months. The person is not sure. And you can see the mild swelling. So my question is… The same question I asked before. So we’ll bring up the poll, if our Orbis host can introduce that. So what is the most likely diagnosis in this patient? Ischemic, compressive, nutritional, hereditary, or inflammatory? And I will give you a few more seconds to vote. 37-year-old. Visual change. Although their central vision is pretty good. And the interesting symptom of vision worsening as they look to the left. So that’s a fairly unusual story. And we’ll see if we can broadcast. We have a little bit more of a mixed bag here. The majority, by a slight margin, are saying compressive. We have some votes for inflammatory, and then some for ischemic. Okay. We can close that poll. Thank you. Let’s look and see. Here’s our patient. Here’s their problem. So they have a benign tumor in their orbital apex. And they have this — what’s been described as gaze-evoked amaurosis. That is looking in a direction and vision getting worse. Presumably because as they do that, their optic nerve gets stretched across an orbital apical tumor. And as they’re looking in that gaze, that optic nerve is being compressed. Maybe it’s not getting the right blood supply. But basically this is the symptom. You won’t hear it much. Of a compressive optic neuropathy. I think the reason that this — the best answer probably is compressive — it’s a 37-year-old, they’ve noted blurriness for some time, but the gaze-evoked thing really brings out the compressive. I don’t want to make it sound like it’s a common symptom that you’re gonna hear with compressive, but if you hear it, it’s probably an orbital lesion. And again, there was swelling of the disc. We’ll talk about that related to compressive optic neuropathy. So the loss was gradual. Usually any time someone says — you know, my vision is getting blurry, it’s gotten a bit worse over the last few weeks or months, I’m thinking not ischemic, not inflammatory. Uh-oh. Could be compressive. Interestingly, it’s usually painless. And patients, when I tell them — yep, it’s a tumor — there’s no pain. I’m surprised. Usually compressive lesions are painless. There are often no associated symptoms at all. People are surprised. I have no other problems. Just this vision thing. That certainly can be compatible with compressive optic neuropathy. Exam characteristics — of course, again, if the optic neuropathy is unilateral or asymmetric, there should be a relatively afferent pupillary defect. There doesn’t have to be loss of visual acuity, although there often is. But like our patient, it could be a peripheral field loss from a compressive lesion as well. You will only see optic disc swelling if there’s proximal optic nerve compression. Proximal to the globe. So if there’s a lesion in the orbit, you may or may not see disc swelling. If the lesion, the compressive lesion, is intracranial, like a pituitary tumor, probably one of the more common causes of compressive optic neuropathy, you do not see optic disc swelling. Unless you have a big brain tumor that’s causing increased intracranial pressure. But compression of the optic nerve in the canal or intracranially, usually, does not result in optic disc swelling. There are rare reports of compression within the canal causing it. But if it’s intracranial, you don’t see it. So if you see disc swelling and it’s compressive, it’s usually gonna be orbital. You might see choroidal folds, which I’ll try to demonstrate momentarily, and optociliary collateral vessels — and/or — and don’t forget to look for orbital signs. If there’s an orbital lesion, look for proptosis and chemosis. So there’s gonna be a RAPD, visual loss, decreased color vision if there’s central loss of vision. Remember that disc swelling is usually only going to occur if there’s compression right behind the globe. This person on the left had a tumor pushing on their nerve. No disc swelling. That’s the most common scenario. Something pushing on the nerve behind the globe, you may see disc swelling. Here’s the disc I showed you earlier. It’s not the best photo. And it’s tough to see this, other than there’s blurring of the disc margins. But when I show you this photo, this red-free photo, which you can see this view with the direct ophthalmoscope, with that green filter, you see the much more obvious radial choroidal folds. Something is indenting the back of this eye. In this case it was a metastatic melanoma, pushing on the eye and the optic nerve. But you might see it with a tumor, you can see it if the extraocular muscles are really big, you can see it sometimes in papilledema, when the optic nerve sheath is extended and indenting the back of the globe. You can see choroidal folds in a small hyperopic eye that are idiopathic and have nothing to do with tumor. Here’s another optic disc. There’s mild swelling. The disc margins are blurred. You can see that there are some Payton’s lines. These concentric folds where the mild disc swelling is pushing the retina aside. But you also see these two blood vessels. Where do they go? It just stops here and here. So these are so-called optociliary or retinochoroidal collateral vessels. You can see these with old central retinal vein occlusions. There can be a tumor, like a meningioma, that is wrapped around the optic nerve. Here you see a nice MRI, cutting right through the nerve, and this is all tumor above and below, encircling that nerve, 360 degrees. So in neuro-ophthalmology, when we think about gradually slowly progressive vision loss, swelling of the disc, APD, we’re worried about an optic nerve sheath meningioma. The pathophysiology is simply that these collateral vessels exist in everybody, but they’re tiny. But if you’ve got something increasing central retinal venous outflow, that blood has to find a different way out of the eye, and that causes these collateral vessels to enlarge and the blood to go out through the choroid and through the vortex veins. You see these vessels. Again, they can be idiopathic, but you need to think about the entities. You can see them in elevated intraocular pressure too. Don’t forget to look for orbital signs. Sometimes this is very obvious. This patient with marked bilateral upper and lower lid retraction and exophthalmos. You might see much more subtle exophthalmos. This patient actually was sent with left ptosis, and it was actually right exophthalmos in thyroid eye disease. Here’s a patient with obvious chemosis and exophthalmos. No questions here. And sometimes if you don’t have a Hertel exophthalmometer, you can increase the sensitivity of your examination by looking either from above, looking down across the corneas, or from below. Sometimes if the patient is sitting in their exam chair, I’ll have them look up towards the ceiling and I’ll look across their corneas to look for more subtle evidence of relative exophthalmos in the eye, with the optic neuropathy, to try to see if this is an orbital process. So here’s an interesting kind of cute case of a young, fairly young guy, 42-year-old, and his chief complaint, believe it or not, was: My vision is getting better. And I said… What do you mean your vision is getting better? He said I’ve worn glasses my whole life, but my left eye, in the last few months, I don’t need my glasses. In fact, I can take my glasses off and see great in my left eye. My right eye is the same I’ve always been. With the glasses on, I’m good. Here he is, better than 20/20. With the correction in the right eye of -2.25. However, in the left eye, which was 2.25, he’s now plano. And the problem is that the referring doctor, the doctor who referred him to me, found there was a small left relative afferent pupillary defect, color vision was slightly decreased, and there was swelling of the disc. Even though the patient was — hey, my vision is getting better, the bad news was you have a tumor pushing on the back of your eye, creating a hyperopic shift, compressing the optic nerve, causing a mild optic neuropathy, with decreased color vision, mild peripheral vision defect, so the good news is you don’t need your glasses. The bad news is you’ve got a tumor. A benign tumor, but it needs to be surgically removed. So I want to just talk about a few pitfalls in diagnosing compressive optic neuropathy. And the three pitfalls that you should try to avoid are: No contrast given on your imaging study. No fat suppression. If it’s an MRI. And the scan — remember, it’s only as good as whoever the radiologist is, or as good as you are. So let’s look at some examples. So here’s a patient. Young guy with optic neuropathy. It’s been going on for a few weeks. And he had been imaged before I saw him. He had a history of Ewing’s sarcoma of the femur that had been treated a few years ago, and was thought to be cancer-free. But because he had a history of cancer, of course he got an MRI, but they didn’t give contrast. This was the MRI, read as normal. We repeated the MRI with contrast, and you can see here that he has a contrast-enhancing lesion in his optic canal, causing a compressive optic neuropathy, which killed him eventually. And so the point here is if you don’t give the contrast, you may miss tumors. Meningiomas are tough to see. Ewing’s sarcoma, which is much rarer, tough to see, without the gadolinium. So it’s extremely rare that I will order an MRI without gadolinium or a CAT scan without contrast. Obviously if there’s kidney problems, and you can’t order it, you can’t order it, but I always order contrast. Or you’ll be worried you may be missing something. And frankly, if you find something without contrast, the radiologist is gonna say — please repeat with contrast, so we can better define the problem. The second pitfall is: No fat suppression. So you can see in the MRI on your left, if you get a brain MRI, a brain MRI, you will see pictures of the eye sockets, but they won’t do fat suppression. And fat is bright white. This is the patient with fat suppression, with an orbital MRI. You can see now the fat signal has been suppressed, and there’s an obvious enhancing optic nerve sheath meningioma that you will not see if you don’t do fat suppression, because the fat is white. The tumor is white. So they look — they blend together. So if you’re thinking… If the patient has a unilateral optic neuropathy, or an orbital process, order orbit MRI. You’ll get brain. But order orbit. I don’t order orbit and brain in the US, because they’ll charge twice as much, which will be thousands of dollars. And here are four MRIs. These are all MRIs that were read as normal. The top MRIs are from patients with what I thought was optic neuritis. You can see there’s enhancement of the distal optic nerve here, where the arrow is. That was read as normal. The chiasm here, just in front of the chiasm, the distal optic nerve, enlarged, enhancing, read as normal. The patient on the bottom left had what looked to me like thyroid eye disease. I wasn’t sure, but I said please look at the extraocular muscles. The scan was read as normal. Yet that inferior rectus muscle is three times normal size. And finally, a patient who had this MRI before I saw them, with double vision, the scan was requested to rule out causes of double vision. This is in a patient with known gastric cancer. This is a gastric metastasis to the superior oblique muscle. This scan was read as normal. So be careful. Radiologists — it depends on your radiologist. How good they are. If you don’t feel comfortable looking at the films yourselves, and you’re surprised, though, by the normal result, call the radiologist and say — please look one more time. This is specifically what I’m looking for. I try to be very specific when I order the MRIs, and tell them exactly what I’m asking for. Nevertheless, I’ll get the report back, and under indication, sometimes even though we’ve given them three sentences as to where we think the problem is and why, all it says on the indication is… Blurry vision. Because the technician who’s scheduling it doesn’t want to write it all down. All right. Here’s a 22-year-old gentleman. Blurry vision in the right eye for one month. They’re 20/200 or 6/36. They don’t see any of the color plates, the Hardy-Rand-Rittler HRR plates, and they have a cecocentral scotoma. Here’s a picture of their optic disc, looks like a little swelling, a little hyperemia of the disc. So typically I would look at this in the United States and say this is probably typical optic neuritis. The problem is that this kid’s brother is a patient of mine. And the brother, who’s 15 years old, has Leber hereditary optic neuropathy. And he had the same thing happen a year ago. It happened in one eye. And then it happened in the other eye. So in this case, I know the family history. And the family history of this is gonna be Leber. And that disc swelling isn’t really true disc swelling. Oh, darn it. I was gonna ask you what you thought. Well, I’m gonna skip that question, since I gave it away. So Leber — hereditary optic neuropathy — usually there’s central loss of vision. Not complete loss of vision. So there’s a cecocentral scotoma with pretty good peripheral vision. It’s painless, but usually one eye. Fairly rapidly. Could be the next day, week, month, but usually within the next month, the second eye will be involved. It’s gonna look like optic neuritis initially. Young, healthy person, loss of vision, possibly what appears to be slight swelling of the disc. Most commonly in men in the 10 to 30-year range, but it’s been reported more than up to age 65, it’s been reported in a 2-year-old, up to 80-something. And although it’s more common in young men, it can happen at any age and it can happen in women. So being a woman doesn’t mean it can’t be Leber hereditary optic neuropathy. As I mentioned, the second eye is involved usually weeks to months. Rarely a much longer interval has been reported. Up to 8 years. The vision loss is usually permanent. Although, depending on what mutation you have, there is a percent chance of improvement, spontaneously, even a year later. The fundus appearance might show what looks like mild disc swelling. But there will be no fluorescein dye leakage on fundus fluorescein angiography, as is shown on this image stolen from this website. The most common mutation is in the 11778 position, but the other relatively common point mutations are 3460 and 14484. For reasons that are unclear to us, the 14484 mutation, if you’re gonna have one of these, is the one to have, with spontaneous improvement in vision in up to two out of three patients. Unfortunately, the 11778 is by far the most common identified mutation, with a much lower chance of improvement. And as you know, this is a mitochondrial problem. It is transmitted from women to kids. Because there’s one mitochondria in the sperm and millions in the egg. So this is not transmitted from fathers. Only from affected mothers to kids. There is no proven treatment. There are some trials going on. Recently there was one using idebenone, which is available over the counter in the United States, on Amazon.com. This study was done in England. It looked at this medication and found no statistically significant improvement, although there were some trends. There are definitely a bunch of — at least a few experimental compounds, drugs out there, that are being used, that I’m told by friends who are using them, have some promise. There is a trial going on at Bascom Palmer Eye Institute in Miami, Florida, in the United States, where they’re recruiting patients who have lost vision in one eye from Leber’s, who are gonna lose vision in the other eye, where they’re doing things genetically. That’s very fledgling status. No proven treatment, as I mentioned. This is some of the data from the study. I’m not gonna belabor this, regarding the treatment of Leber hereditary optic neuropathy. At the moment, no proven treatment. And then the other hereditary optic neuropathy that we see, also no proven treatment, is dominant optic atrophy. So dominant meaning that it’s a dominant gene. So one of the parents should have it, and each child has a 50% chance of having the condition. This is usually detected in asymptomatic children. In the United States, kids usually have a visual screening before going to school at the age of 5 or 6 and they’re found to be in the 20/30, 20/40 range, 6/12 range, the kid doesn’t know their vision is not bad. That’s just the way it’s always been. They’re not complaining. They get sent for glasses, their glasses don’t help, and usually you’ll see some relative temporal pallor of both optic discs. The color vision usually will be decreased. The parents may or may not say they have a problem. I usually check the color vision in the parents, if they’re both there. And usually one of them has poor color vision at least. If they don’t know they have the problem, they were never told they had it, because their vision is in the 6/12 or better range, and they’re asymptomatic. Now, this has a very variable course. So it can gradually worsen over years and decades. I certainly have people who are legally blind from this condition by the time they’re in their 40s. I have people who really have not had a big change in vision over decades. So it may slowly progress. It should not rapidly progress. Or it may not progress. There is no treatment we know of to prevent progression or to fix the problem. In the United States, we can obtain these blood tests. They cost more than $1,000. There is no treatment and insurance in the United States usually doesn’t pay. Patients usually don’t want the blood test. Visual fields are typically the same sort of look as Leber’s. That is, there’s cecocentral scotomas, like you see here. Again, this doesn’t make you blind-blind. Your peripheral vision is usually pretty good. People are actually usually very functional. Maybe can’t drive, but do well, typically. Here’s another patient, with a retrobulbar optic neuropathy. So when I use the term retrobulbar, that simply means that the person has evidence of optic neuropathy, but you look at their fundus and their optic nerves look normal. This is a 44-year-old gentleman, blurry vision, both eyes for about a month. It’s gradually getting a little worse. He’s 20/40 or 6/12 in both eyes. He misses most of the HRR color plates, and his fields look like this. He’s got the cecocentral scotomas. So the question is: The same question that we’ve seen before. We have the poll. What do you think is going on? This is a bilateral, fairly symmetric process. He’s symptomatic, and it’s been a couple months. He thinks his vision has been okay prior. There’s been no pain. His fundus is normal. His fields are as I showed you. Sort of central, cecocentral scotomas. I’ll let the Orbis host decide when to call it. He knows about how many votes we’ve been getting in the past. Let’s take a look at what people think. The majority of you have the correct answer. This is probably nutritional. Probably not ischemic or inflammatory. Why not? Those are sudden onset. This is gradual and getting worse. Hereditary? It possibly could be. This could potentially be Leber hereditary optic neuropathy. You don’t have to see what looks like disc swelling or pseudodisc swelling. He’s 44, a little older. It’s bilateral and symmetric. Potentially — it’s in the list. Compressive, yeah. This could be compressive. It would have to be very symmetric, bilateral, so we’re not thinking about bilateral orbital process. It could be an intracranial process, symmetrically compressing both… Pretty rare. And honestly, I’ve never seen a compressive lesion cause cecocentral scotoma. So nutritional optic neuropathy is usually gradual bilateral painless visual loss. Often in alcoholics in the United States who drink all their calories. The question is… If you ask them if they drink, yeah, one glass a day, ask them how big the glass is. What does that mean? It’s not uncommon for someone to say… Oh, what do you like to drink? Gin. How much? Oh, you know, a quart a day. And that’s not uncommon. And the general rule of thumb is double whatever they tell you. But if you drink that much, you’re probably not eating a lot of food and getting the right nutrition. So they often have central or cecocentral scotomas. The disc may be normal. Ultimately, of course, and unfortunately, they become atrophic, and then it’s permanent. We look for these patients’ vitamin B12, serum folic acid, red blood cell folate, thiamine, or B1, and if the person has a history of gastric bypass surgery for weight loss — and it’s important to get that history, because people with gastric bypass surgery often have poor nutritional absorption — I will also check a copper level. So copper deficiency optic neuropathy is relatively recently described. I’ve seen a couple of cases. I only check copper, at least in the United States, in patients who have had gastric bypass surgery. But red blood cell folate is kind of like a hemoglobin A1C in diabetics. Hemoglobin A1C is kind of a measure of your chronic blood sugar level. Blood glucose level. So is red blood cell folate for folate. So if the person goes to the doctor in the morning and decides I’m gonna have a good breakfast this morning, their serum folate may be normal. And in a paper we wrote on folate deficiency optic neuropathy, we reported six patients, three of whom had low serum and red blood cell folate levels, but the other three had normal serum and low red blood cell folate levels and they all improved with folate supplementation in their diets. So that’s sort of what I have to say about nutritional optic neuropathy. Now, around the world, that may be way more common than in the United States, where we really only see it in alcoholics or maybe after gastric bypass surgery. Here’s another patient. A little older. 66. With another bilateral retrobulbar optic neuropathy. Their visual acuity is down some. 20/40 or 6/12 OU. Visual fields look like this. Color vision is down. And because of the visual field defect, which looks kind of bitemporal, they had already had a MRI. The MRI was said to be normal. I looked at the MRI. It looked normal. But they didn’t get the important part of the history. And this is this patient was on ethambutol for mycobacterium, and they had ethambutol toxicity. Which is by far the most common toxic optic neuropathy I see in the United States. And it’s certainly very common in countries where there’s a lot of tuberculosis. So Philippines. Common ethambutol optic neuropathy. One of the most common forms of optic neuropathy. It’s usually fairly symmetric, like nutritional. It’s a systemic problem. And I always warn patients — first of all, you need to stop the ethambutol. I talk to their doctor who prescribed it. And I warn them — you may get worse before you get better, even after you stopped it. Here’s the same patient, who came back after six weeks. He was worse. Now he’s 20/100 and 20/80, terrible-looking bilateral cecocentral scotomas. I repeated the MRI because I was worried that we missed something. Normal MRI. And sure enough, after we waited another six months, five months, his vision was back to 20/25, almost 6/6, and his visual fields were almost back to normal. I usually treat these patients — and this is not evidence-based — but I treat these patients with copper and zinc supplementation in the form of Ocuvite with lutein. I have no financial interest in Ocuvite, but it has a lot of copper in it. Ethambutol works as an antibiotic by chelating metal ions. And you need some of the enzymes in your electron transport chain — need metal ions like copper. And so you need to supplement them. Now, that’s not evidence-based, but that’s what I do. So ethambutol, optic neuropathy. Common form in the United States. By far, most common form, toxic optic neuropathy. So in summary, for this webinar, ischemic optic neuropathy is usually sudden, painless, and the disc is usually swollen. And it’s usually, in the US, non-arteritic anterior optic neuropathy. Posterior ischemic optic neuropathy is rare outside of dialysis, hypotension, surgery. Some obvious recent bad low blood pressure. Blood loss. Something like that. Hypoperfusion. Compressive optic neuropathy is usually painless. Make sure you get the correct imaging, like we described. Leber’s hereditary optic neuropathy may mimic optic neuritis, but the clue will be the other eye is affected within a short order. Nutritional, toxic optic neuropathy should be suggested if you take a good history. So that’s my summary. Now, there were some questions I’m not gonna go into right now. I’m gonna have some other questions that I think our Orbis host will be able to bring up the questions that have been typed in on the screen. I believe. I’m thinking for our next webinar — I don’t think it’s been advertised, but I think for our next webinar, I’m gonna periodontal try to cover papilledema, because we haven’t talked about papilledema. And then it’ll be sort of a papilledema webinar, but I’m gonna throw in 15, 20 minutes on differentiating glaucomatous optic neuropathy from neurologic optic neuropathy. I think maybe I click on the question and answer thing up here. Yes. All right. So I’m gonna start with the first question here. Which was: Well… Not sure it’s a question. It just says NAION/GCA… That’s not really a question. What are the routine investigations you advise in AION? So, again, it depends on whether you think this is non-arteritic AION or arteritic. In the majority of people, it’s non-arteritic. If they haven’t seen their physician in the last six months and haven’t had cholesterol, blood pressure, diabetes checked — they need those checked. A blood pressure and fasting glucose check. If there’s a suggestion of sleep apnea, these days I recommend a sleep study. If they have high blood pressure and are taking blood pressure medications at night, I recommend taking them earlier in the day. If there’s any chance I’m thinking this could be giant cell arteritis, then clearly they’re gonna have a sedimentation rate, a CBC with platelets and a C-reactive protein, and depending on my level of suspicion, I might start them on steroids before I get the results, and then of course obtain a temporal artery biopsy. The next question is: How to differentiate between retrobulbar optic neuropathy and posterior ischemic optic neuropathy? So posterior ischemic optic neuropathy, early on, is a form of retrobulbar optic neuropathy. Oh, I’m sorry. Maybe that should be retrobulbar neuritis. So I’m gonna assume this is… How to differentiate between retrobulbar neuritis and posterior… And the answer is… Very difficult. Certainly in a young person with no vascular risk factors, who’s not on dialysis, and has not lost a lot of blood, it’s never gonna be posterior ischemic optic neuropathy. It’s always going to be pretty much — it’s gonna be retrobulbar optic neuritis, although I’m going to get an imaging study to make sure it’s not a tumor pushing on their nerve. But in an older person, then there is no way to differentiate. Certainly if there’s a lot of pain, pain with eye movement, I’m gonna lean towards neuritis and not ischemia. And again, if it’s an older person, even if they’re older, with vascular risk factors, if there’s no history or cause of extreme low blood pressure or blood loss, then it’s just very rare to have a PION. All right. Is there any rule for… Ah. Fluorescein angiography for PION? Well, certainly that can be helpful — for me, it’s usually — I mean, usually helpful in the setting of — could this be giant cell arteritis? So giant cell arteritis — I may not have mentioned it — I should have, but I didn’t — can definitely cause posterior ischemic optic neuropathy. Although most likely it’s gonna be an anterior ischemic optic neuropathy. Giant cell arteritis can cause a posterior ischemic optic neuropathy. So I am gonna think about that in anybody who has sudden loss of vision in the right age range. And the way that fluorescein angiography helps is poor delayed choroidal — poor choroidal circulation. If you see that in someone where you’re thinking about GCA, then that’s good evidence of GCA, of giant cell arteritis. Question: What is definitive diagnosis of PION? There probably is no definitive diagnosis of PION. It is gonna be… There’s no test. It’s gonna be in the patient with what I just mentioned. Bad choroidal fluorescence, with fluorescein angiography in giant cell arteritis. It’s gonna be someone who awakes from surgery with a unilateral or bilateral optic neuropathy, normal fundus, lost a lot of blood, had low blood pressure. So it is a diagnosis of exclusion. And assumption. Is it possible to differentiate the compressive and hereditary neuropathy on seeing fundus photos alone? If you see choroidal folds, like we talked about, the radial choroidal folds, indicating something is pushing on the back of the eye, or you see collateral vessels, that’s not gonna be hereditary, unless of course they’re idiopathic. So, that said, the more common scenario would be normal fundus or mild pallor, and there’s no way to differentiate heredity from compressive. And I think in the next webinar, now that you mention it, I’ll throw in a little bit about optic atrophy. We did a study some years ago, and found, in people with unexplained optic atrophy — and I’ll talk about this next webinar — unexplained optic atrophy — we had 97 patients in our study from the University of Cincinnati and the University of Iowa, of the 97 patients with unexplained optic atrophy, all of them got imaged. More than 25% had a tumor. So you can’t just look at a pale nerve — and we’ll talk about that next time — and say ah-ha, this was caused by X, Y, or Z. All right. What do you think about… Maybe I should start at the newest one. Hold on a second. What do you think about the three-parent strategy for mitochondrial inherited conditions? I only heard about it recently, whereby they remove the mitochondria… Oh, so this is a question relating to, I assume, to treatment of mitochondrial inherited disorders, and my answer is honestly… I don’t know anything about it. That is not what they’re doing in the study at Bascom Palmer on Leber hereditary optic neuropathy. So I will have to read up on it. I don’t know anything about it. How many milligrams of copper? Okay. I usually want them to get at least 2 micrograms of copper a day. 2 to 4 micrograms. And it’s really more the copper than the zinc. In the Ocuvite with Lutein, what I use — the pills are 2 micrograms per pill. I usually have them take 2 per day. Steroids for treatment of acute traumatic optic neuropathy with no light perception vision — no fair. We didn’t talk about traumatic optic neuropathy. Maybe I can throw that in as a miscellaneous next time. So there is no evidence base for treatment of acute traumatic optic neuropathy. The only study that was a crappy study, terrible study, was a survey study on that, and the bottom line of the study was — there is no standard of care. I usually do use low to moderate doses of steroids for traumatic optic neuropathy. Not megadoses that they used to use. I used for a while — from the… The study that… The NASCIS study, the acute spinal shock treatment study — for a while, some years ago, we were using mega, megadoses of intravenous steroids. I don’t use those anymore. That was shown to probably not be good and maybe bad. I do use either oral or intravenous steroids in acute traumatic optic neuropathy, whether it’s NLP or whether it’s 6/12, I use them for a week or two. If there’s improvement, I continue them. If there’s no improvement, I stop them. I use anywhere from 60 milligrams of prednisone a day to 1,000 milligrams of methylprednisolone, intravenous, followed by oral prednisone. Okay. Hold on a second. Someone is asking me to show the last slide. I’m gonna get to that last slide. I’ll move those questions out of the way if I can. I’m not sure if the questions are covering your slide or just mine. All right. Is it possible for… NAION for patients who have postpartum hemorrhage? Sure. You can have an NAION, you can have a PION — if you lose enough blood, for whatever reason, you can have either an anterior ischemic optic neuropathy or a posterior ischemic optic neuropathy. What is your overall experience with ethambutol-induced optic neuropathy? So overall, my experience is that people usually have good recovery of vision. Now, I think — it depends, of course, in a sense, on how bad their initial vision is. So, in general, having better vision at diagnosis bodes — is a good prognostic sign for recovery. The only patient I could remember who didn’t have pretty good — and when I say pretty good recovery, I mean in the 6/6 to 6/12 range — is a plastic surgeon who was being treated for tuberculous renal failure. And they misdosed him. Because ethambutol is cleared through the kidneys, he was on way too high a dose. I didn’t see him until he was light perception AU. And he had no recovery. And he won a big malpractice settlement. He had no recovery of vision. So I always warn people, as I said, your vision may get worse even after you stop the medicine. And then I wait and I see them in 6 or 8 weeks, see where they are, and tell them hopefully over 6 or 12 months, you’ll have gradual visual recovery. Would you stop steroids in giant cell arteritis, even if the CRP is not really back to normal or going up or down? So I don’t base my treatment of giant cell arteritis much on the blood tests. My routine treatment for giant cell arteritis is… My routine is actually high dose oral steroids. 80, 100 milligrams to start. Rarely intravenous, but usually I treat them with 80 or 100 of prednisone. I decrease their dose by 20 milligrams a month, every month, until I get to 40 milligrams. So 100 for a month — 80, 60, 40. At 40, I go to 30 for a month, 20 for a month, 15, 10, and then I leave them on 5 for the duration of one year. Of course, there can be side effects and problems. I try to manage those with their family doctor during the course of that year. At the end of the year, I tell them that we could try to get them off or just leave them on 5 forever. People who’ve lost vision usually opt for the 5 forever. I can tell you, knock on wood, that in doing that, I have never had someone lose vision in their good eye on that protocol. In 27 years. I tell the patient that that treatment is not to help the vision in their already bad eye, if they have a bad eye. I tell them the first week after starting the steroids is the crucial week. That you could lose vision in that first week, but if you don’t, you probably won’t. So I do check blood tests, along the way. Usually I don’t even check blood tests until we get down to 20 in that scheme I just mentioned. Because the steroids are gonna lower it. The CRP is fairly meaningless to me. But I base my treatment mostly on recurrent symptoms, and the combination of symptoms and the sed rate. If PION is a systemic fall in blood pressure… Why is it so often unilateral? Good question. No idea. It probably has to do with the individual nature of the blood supply to the nerve. In other words, the question that people… That the neurosurgeons and the anesthesiologists ask is… Why that person? There was nothing different about that case, in terms of the low blood pressure, in terms of the amount of blood pressure — excuse me, the amount of blood lost. There was no difference in that case. The person is blind. Those other 100 patients have normal vision. You look at their record — no difference. It probably has to do with just the individual variations in blood supply to the optic nerves. And that’s about as good an answer as I can give you. Hold on a sec. How can you distinguish pseudo-Foster-Kennedy syndrome from Foster-Kennedy syndrome? You can’t. Neuroimaging is the only way to differentiate. For those who aren’t familiar, perhaps, with the term — so Foster-Kennedy is a unilateral disc swelling with contralateral optic atrophy, described by Foster-Kennedy in patients with giant brain tumors big enough to cause compression of one optic nerve, and increased intracranial pressure and swelling of the opposite optic nerve. Very rare. At least in the United States. I’ve seen that once in 27 years. So the vast majority of my patients with what appears to be a Foster-Kennedy syndrome have pseudo-Foster-Kennedy syndrome, and sequential non-arteritic anterior ischemic optic neuropathy. Correct to stay altitudinal… Yeah. I think, well,central, cecocentral, will still be unlikely in pseudo-Foster-Kennedy. You’ll have crappy visual fields in the eye with optic atrophy.. It’s not gonna be cecocentral. I’ve never seen a compressive lesion causing cecocentral scotoma. And you’re right. Altitudinal is more likely gonna be NAION. I don’t think it’s proof. It might make me feel a little better if I don’t have any imaging. But remember, if it’s a true Foster-Kennedy, it’s gonna be a big tumor. Even a non-contrast CT is gonna show you that. If you can’t get a non-contrast CT, that’s a problem. I would feel a bit better if you get imaging and the person has bilateral altitudinal defects. That would make me feel better, but I don’t think it rules it out absolutely. I’ve seen tumors cause altitudinal field defects. Is there any connection between PT, APT, and INR in a patient with NAION? Not that I know of. Any benefit to start on anticoagulation treatment? No evidence base for anticoagulation treatment. Now, there have been a couple of retrospective studies that looked at aspirin. The problem is the studies basically are retrospective. What they do is they look at patients who come in, who develop NAION on aspirin, or off aspirin. And one study showed no difference. One study showed maybe aspirin was helpful in preventing a second attack. A sequential attack. The bottom line is there’s not great evidence for it. I usually recommended aspirin. I tell them — listen, we don’t have good evidence. Usually they have other risk factors that aspirin might benefit. Me, personally, if I had NAION in one eye, I would probably take a baby aspirin, 81 milligrams, a day, unless I had some side effect that was preventing me from doing it. Let me see where I am here. What is the prognosis of compressive versus nutritional optic neuropathy? Both, I think, depend on how long has the compression or nutritional problem been present, is there already optic neuropathy, and of course these days OCT will tell you if they’ve lost nerve fiber layer. Obviously if they’ve lost nerve fiber layer on OCT, the prognosis is not real good. If they have optic atrophy, clearly there’s some permanent damage to their vision. If they’ll come in with normal-looking discs in either competitive or nutritional, normal OCT, then the prognosis is probably pretty good, as long as you can get rid of the compression or get rid of the nutritional deficiency. Why is it definitely not NAION if there’s no swelling? Because the A in NAION, the A in NAION stands for anterior. In the anterior means you have to have optic disc swelling. It’s… I don’t know. I’m trying to think of an analogy. Well, it’s like saying — why can’t the person have a retrobulbar optic neuropathy and they have disc swelling? Because they have disc swelling. You can’t have a retrobulbar optic neuropathy if there’s swelling of the nerve, by definition. So it’s simply a definition. What do you use to treat dominant optic neuropathy? Nothing. There is no treatment for dominant optic neuropathy. What about citicoline in traumatic optic neuropathy? I have no idea. Maybe I should look it up. I’ll write it down. Never heard of it. Do you ever use ultrasound to diagnose giant cell arteritis? So rheumatologists oftentimes will use ultrasound of the temporal artery to diagnose giant cell arteritis. I never use it, because I don’t consider it the gold standard, number one. Number two, I’ve certainly had patients with normal temporal artery ultrasound and positive temporal artery biopsies. And so, again, you’re considering a condition that can make you bilaterally blind forever. I want the gold standard diagnostic testing for that condition. If a patient is NLP, any indications for treatment? Sure. I think so. If the person is NLP, I mean, first of all, I certainly see optic neuritis, typical and atypical optic neuritis that is NLP, who respond — the atypical optic neuritis patients — who return to 20/20, who are NLP. I’ve seen neuromyelitis optica after plasmapheresis return to 20/20 from NLP. We’ve reported thyroid compressive optic neuropathy, NLP, with recovery of vision when the compression is removed. Have you ever witnessed recovery of vision of — okay, so I just answered that one. Certainly it’s common. I’ve seen recovery of vision from NLP with no treatment in typical optic neuritis as well. Typical optic neuritis. Do you see much vigabatrin toxicity? No. It has been reported to cause retinal toxicity. I don’t see much of it. It’s not used a lot. And I don’t see lots of kids, because we have a huge children’s hospital, so I think they might see it more than I do. And I would stop the drug if you see it. I don’t know if it resolves. It’s a retinopathy. We don’t see the slides you see… Oh, so one viewer says we don’t see the slides you see and talked about a couple of times during your speech. You just see them. Okay, that’s interesting. I’m not entirely sure how that could happen, but thanks for that information. Maybe next time we’ll ask — if you think you’re seeing a slide that you’re not, write down what I’m talking about, because I just kept advancing slides and talking, per usual. We do recommence — do we recommence ethambutol after vision recovers? No. High dose of vitamin B in toxic optic neuropathy — in toxic? I don’t use high doses of vitamin B in toxic optic neuropathy. I use high doses of vitamin B12 in B12 deficiency optic neuropathy. Older TB patients do not recover vision better than younger? I don’t have that experience. The patients that I’ve seen — and again, I’m not sure. If you’re talking about tuberculous optic neuropathy, infectious optic neuropathy, I have never seen a case of tuberculous optic neuropathy in the United States. And I have really no experience. I’ve seen it in India and other countries, but I don’t have a chance to follow those patients. If you’re talking about older tuberculosis patients who take ethambutol and have ethambutol optic neuropathy, I have seen older patients recover vision. I have not found there to be any difference in recovery if it’s an ethambutol optic neuropathy. I don’t know the answer if it’s tuberculous actual infective optic neuropathy. Would you use only steroids in GCA? So certainly acutely, I would only use steroids in GCA. The time I would use other medications, say methotrexate, something like that, would be if the patient were trying to taper the steroids, like I discussed, and were coming down, but we can’t get lower than, say, 20 milligrams of prednisone or 15 milligrams of prednisone. Every time we get lower, they have recurrent symptoms and/or the blood tests go way up, that would be the time I would consider adding a steroid-sparing agent. I usually work with a rheumatologist when I do that. I don’t prescribe it myself. And once the rheumatologist tells me that the immunosuppressive agent seems to be working, then we try again to taper the prednisone or the steroids. Is there a role for idebenone in Leber’s? So there’s a study that’s looked at that, as I mentioned. The study did not show a statistically significant benefit to using it. There was a trend, they like to say, but it did not show statistically significant change. Will MRI show signal in PION? Interesting question. It might. I’m actually reviewing a case for publication from a journal where they’ve shown — they have an MRI done with diffusion-weighted imaging, which is great for looking at ischemic brain, and they study — and there have been other reports of ischemic optic neuropathy being identified on MRI, if you use diffusion-weighted imaging. Let’s see. Somazina is citicoline, and some advocate it for AION. I’d have to look it up. Never heard of it. Somazina. I’ll write it down. I would be shocked if there’s any good data, since I routinely talk to people around the world, and no one’s ever mentioned it to me. I’m in Berlin, Germany. No problems seeing the slides or hearing your voice. Good. Yeah, I don’t know why a slide would not show for an individual. It might be that they were just mistaken about the slide and maybe I was talking about something that didn’t seem right or something. How to differentiate between normal tension glaucoma and optic neuropathy? Okay. Tune in next time. I’m gonna include that in my next neuro-ophthalmology webinar. And we’ll do a potpourri. We’ll do papilledema, we’ll do is it glaucoma or is it neurologic, and I’ll throw in maybe very briefly a little bit about traumatic optic neuropathy, and I’ll try to add in whatever I can find on Somazina/citicoline, since obviously I’ve never heard of it. Okay. Also good from Egypt. All right. That is the end of the questions. So I think I will stop there. Hopefully there was some good information for people, and I look forward — I don’t think we’ve scheduled for sure the next neuro-ophthalmology Orbis webinar, but I appreciate it. Hopefully we’ll see some of you — we’ll be in Singapore at the Asian Pacific Academy meeting in February, and I’ll be elsewhere around the world the rest of the year. So I look forward to seeing and hearing from you. I have one more about traumatic optic neuropathy. What is your approach? So again, with traumatic, we’ll talk more about it next time. But usually, if they’re an inpatient, and are gonna be in the hospital anyway, I use 1 gram of methylprednisolone a day for a few days, and then oral prednisone, 60 to 80 milligrams of prednisone, for a couple of weeks. See if they’re improving. If there’s some improvement, then I gradually taper. If there’s no improvement, I rapidly taper. Okay. I’m gonna sign off. Thanks, everybody, for tuning in. Have a great day, and happy new year’s.