 When we get started, we're talking about functional vision loss today. So just kind of some introduction to this. Your first job, when you have a patient come in and you kind of suspect this doesn't all add up, it seems like it might be functional, is to make sure that you exclude any organic causes of vision loss. That should be kind of like primary thing that you're trying to figure out is could there be something organic going on, is there something really subtle? And then always keep in mind that patients that have organic disease may also have some superimposed non-organic behavior, and this is about like 15% of functional vision loss. So that can be really hard to tease apart. So maybe even if their story doesn't completely make sense, there is something going on, but not all of it is organic. And then page into things like, you know, does the patient sign into the reception desk? Do they walk into the room and sit in the chair for supposed to be NLP? If you outstress your hand to shake their hand and don't like give them any verbal cues, do they shake your hand? And so just be aware of their story and any secondary gain features. Malingering is willful feigning, which is sometimes different than functional vision loss or like a conversion disorder. And then munchausen syndrome is creating a real disease by self-inflection. So that's not really, truly functional. I think Dr. Shakur had an example of like a lady who was using laser pointers and pointing them at her macula. So that would be like an example of munchausen syndrome. And then conversion disorder prevalence is 11 to 300 per, should be 100,000, and they occur in both children and adults, but they're more common in women than men. And the mean age of children with functional vision or with conversion disorders is about 10 years old. And then in about 65% of people, both eyes are involved. And then in the bilateral cases, both eyes are usually affected to the same degree. And in the unilateral cases, usually the vision loss in that one eye is worse than the vision loss in that it would be in a bilateral case. And then decreased visual acuity and constructed visual fields are the most common symptoms or complaints with functional vision loss. And a strong indicator of organic disease is if you see a central scatoma on visual field testing. So that's kind of like a red flag and rethink things if you see that. What are some organic vision loss causes that may be really subtle early on and could be mistaken for functional vision loss? Can you think of anything? Yeah, good. What did you say? What about other macular pathologies maybe that are even common? What's that? Yeah. Or think about a young person. CSCR. Yeah. So CSCR can be like, if you're just looking in, sometimes it can be hard to see if you don't get an OCT or if you're not looking for it. Like that syndrome? Yeah. Good. B-R-A-O. What's that? B-R-A-O. Yeah. B-R-A-O. Yeah. If you're not looking for it. What's that? Stargard. Yeah. Stargard, especially early on. You might not be able to see a lot of changes. So it's also important to like ask about family history and things like that. So we'll go through these. So idiopathic big blind spot syndrome or acute zonal occlu outer retinopathy they're kind of on the same spectrum. Gives you a large blind spot. And then oftentimes on their macocee teeth and kind of see this like stippling of the ellipsoid zone where it's disrupted, especially near the optic nerve. Bilateral retrochiasmal disease can, you know, you're not going to see anything really on exam. And so be aware that, you know, to look for that, especially if there's anything in their history that might suggest that to be the case. And then chiasmal disease without optic atrophy like craniopharyngeoma, conorad distrophy like Sarov said, later on their macula is going to look abnormal, but especially if it's like early on and you're just not looking that closely, you're not looking for it, it might be hard to tell. Really keratoconus or any type of a regular astigmatism where they're not going to, you know, refract to 2020. But if you don't, they're not going to refract and especially like if maybe you can get them to pinhole better, but you can't get the refraction better. Think about getting a topography. Or if it's keratoconus that's progressed enough, then it could cause enough problems that they may not even have best corrected visual acuity to 2020. And then early PSC cataracts. And PSC cataracts are something that a lot of times people will just like notice all of a sudden, especially I feel like I've seen a lot of patients at the VA where it's like they have sudden onset vision loss and they just have this PSC cataract that's like probably crept into their visual axis and but a lot of times people, it's like one day they notice it and then levers maculopathy like CSCR or an ERM and then perineoplastic retinopathy, especially if the history fits retinitis pigmentosus in pigmento. So you would still expect to have some of the other findings like arterial narrowing and they're going to have you know, outer retinal loss paraphobeally, but that can be a lot harder to see if they don't have the classic bone spicules. So you can see this patient, they don't really have the classic bone spicules, but they still have the outer retinal loss on OCT. And then retro bolvar optic neuropathy and then stark heart disease, especially if they don't look like this to start with, it can be subtle to start with. So if a patient is bilateral NLP, there's some tests that you can do. This is probably the easiest one to figure out whether they really can't see anything at all because you're just looking for any type of vision. So there's the finger touching tests where you ask the patient to touch the fingertips of each hand together, and this is an appropriate reception test in opposition. So if they act like they can't do it, a bilateral NLP patient should still be able to touch their fingers too. And then pupillary reactions, a normal pupillary reaction suggests that the anterior visual pathways are attacked, but obviously doesn't roll out some types of organic disease that are retro, that are optic radiations and oxybital lobe and so forth. You can test OK and drum, so you slowly rotate the OK and drum in front of the patient and you look for eye movement. And this, similar to the mirror tests where you slowly rotate the mirror from side to side in front of the patient and look for eye movement. And then electrophysiologic testing, flash and pattern reversal VEPs. We think of this as more of an objective test, but just bear in mind that you can still willfully suppress VEP by not being attention to it or kind of defocusing on the stimuli from the screen. And it can still give you false positive and false negatives, it's not a perfect test, but it's just kind of another thing that can add to whatever the overall picture is. So how does that work for the EUA's and VEPs? Yeah, they put the contact lens on and that's why they cover the other eye, because it's like a flash. Or not the contact lens, it's a goggle. Right, this one is like the black and white randomly changing ocular random patterns. But yeah, I guess that one is more objective because it's not awake. But even so with that one, I've seen it like not correlate to the last one or just, you know, sometimes there's a limit to how much you can tell you. Okay, the next section is monocular reduced vision. It's kind of, it's a little bit harder to tease out. Someone is, there's two types of reduced vision right there. Someone who says they can't see anything at all in one eye and those people who say their vision is decreased in one eye. No vision in one eye is a little bit easier to tease out versus just decreased vision in one eye. So the first thing that I always look for when someone says they can't see out of one eye is look for an APD. It's really, really substantially increases but does not confirm the likelihood of non-organic vision loss. So it's just a lot less light, it's a lot more likely to be non-organic if they don't have an RAPD. And just in case anyone doesn't remember how to check an APD, flashlight test there. So another test you can do is the base out prism test. So use a four sixth after prism, place it in front of the bad eye with a base out. So make sure you know what GIA is, you know, the problem I, and then, so the normal response is that normal eye will flick in and you'll get the stochotic correction or it's kind of this convergence. So you'll see, basically you'll see the eye that's covered move. If there's any movement of that eye, they're seeing something out of that eye because the brain wouldn't refix it through the prism if they weren't seeing anything. So just a quick way to put up there and see what happens to that eye. Then vertical prism association, this one relies a little bit more on the patient, you know, telling you what they see. So you put the four prism base down in front of the good eye this time and so normal vision would see two readable lines. And if they're really not seeing out of one eye, then they'll only see the one line of that line will be blurred. So that one again requires the patient to cooperate a little more. So then there's these things we call confusion tests. So the key to confusion tests is patient, they must be unaware which eye is being tested and they also have to think it's part of the normal exam. If you tip them off that this is something kind of unique and we're doing just to see if you really see it, these are easy to kind of fake. It's, you know, kind of say something even if it's wrong but just to kind of fake it depending or even if it's a subconscious faking. I don't know if that's the right word, but to not acknowledge what they're actually seeing. So the first one I'm going to go over all these fogging tests, the duochrome test, the polarized lens test, and the stereopsis testing. So fogging, place a trial frame in front of the patient's face, cover the bad eye with two cylindrical lenses. There's a lot of very different ways to do this. This is the one BCFC suggested. So you put the, let me show the picture here, make it make sense. So you put the trial lens on and you get a minus six lens and a plus six lens and you line up the axis. So they're basically canceling each other out. And I think it's probably useful to put another lens in the other eye since you are trying to sort of go with this, we're testing both eyes idea. And then as you have them start reading the lines, you slowly rotate one of the lenses so that you're inducing a lot of stigmatism. So it should get, by the end of it, it's going to be a 12 after spread, which is really hard to read through. So if they continue to read without any problems, then it indicates that they're seeing well. So you have as you read the good eye, sorry you're fogging the good eye. I should clarify that as you're doing this so that you can see if they're still reading with the bad eye. The key breathing means here she has some vision out of the bad eye. Next one is the duochrome test. So you get the red green glasses that we use for like the worth four dot test. You put the red lens over the bad eye. That's how we can remember because red is bad. You put on the red green filter on the snow on chart. And the green lens over the good eye, so Gigi helps you remember which eye I keep it straight, prevents the patient from reading the red letters because of the way the lights filter. So if she can read, here she can read the letters on the green side, the patient is seeing out of the bad eye because that's the red eye, red covered eye. So this is what they would see with both eyes. They truly have vision loss and they have the red filter over the bad eye. They would only see the red side, I say that right. So then polarized lens test. So before you put polarized lens on the patient, you have to check and make sure you know which one is blocking the light. Because the polarized lens test we use for a clinic, they have one as polarized vertically, one as polarized horizontally. So you should want to make sure you know which one is which. Because most screens will send the light polarized, including our snow and charts upstairs on the computers. So you can test this yourself sometime and put it on. And it will walk, one eye will walk the polarized light in the correct orientation. So place the polarized lens over the patient's face, walk the bad eye, and you project the chart. So you gotta know ahead of time which one's which or else it's just gonna confuse you. And then so you project the light and then again, just having to read. If they can read the chart with both eyes open and you're blocking the good eye, then you know they can see. And stereopsis testing, this one's kind of obvious. If there's, to have stereovision, you have to use both eyes. So if they have any stereopsis, then they are seeing out of both eyes. One thing though is that there's some tables and some ideas of how this correlates, like how much stereopsis they have that correlates to actual visual acuity. It's okay, it's not really great though. You can't kind of hang your hat on and say, they saw 300 arcs of stereo, so therefore they have 20 X vision. Just keep that in mind. It's not really good to correlate those things. And then I just want to re-emphasize the fact that if you need to kind of some trickery and some magic and confidence and sort of, okay, now we're gonna do this and make it seem all normal. So they gotta take you seriously. The last couple of slides, I'll talk about binocular reduced vision. So a couple of things, so when somebody has binocular reduced vision, the question is, what can you do to bring out a possible non-organic cause? This is a test that if you haven't rotated neurophomology out for the residents, you'll see this done quite a lot. I've seen this done by Dr. Crumb, Dr. Katz, Dr. Degree. I've done it myself. I think it's a really useful, easy test. So the scenarios of a patient comes in, I can't see in both eyes. I can only see maybe the E on top line, or at least can see some letters. And so what you would do is start with a show them the 2010 line and tell them, can you see any of these letters and say, no, no, I can't really see it. And you could ask them, how many dots are there or how many letters are there? And say, no, no, I really can't. I really can't, I said, all right, and then you can continue encouraging them. Maybe the first letter is a little easier, keep going and say, no, no, no, I really can't, and then go to the 2015 line and do this again. And then if they can't read it, say, this is double the size already. Maybe the next line will triple, quadruple the size, it'll be harder. And then you give them a 2020 line and they say, I think I can see now I see five letters. All right, can you see the first letter, I still can't. Really try this is bigger and then 2025 line they can read. So I've seen that happen all, so it's a really good test. And again, reading better than the previous exam suggests a non-organic component. So it's a really quite useful test. So that's the first test bottom up acuity. This is something that we don't use in the neurophomology a lot. I've never seen this, but this isn't a BCIC, I just want to go through everything. But some people say, I can't read letters. Okay, we can use a tumbling E-chart, see if they can read those. You can use chart with numbers. The other thing that just reminded me is some people say, I can only read a top line. So give them a Stelen chart that has a top line with 2050 and all of a sudden they can read it. So those are some maybe useful tricks. There's also other things that you can do, visual aids. You can give a trial frame that you just put basically multiple lenses, but equals what their correct prescription. And you can give suggestions that these are special, magnifying lenses and see if you can get them to see a little better. A potential acuity meter can also, you can tell them that this can bypass the visual block and see if they can have any improvement in vision. Okay, it's a kind of a pinhole test. So these are other tests that are not in the BCSC that I just wanted to let you know that there's other tests and I've also learned a couple of new things. First, near vision testing, near vision testing and distance vision doesn't really correlate. Okay, but if there's a large discrepancy of what somebody can see near and at distance, that may suggest a non-organic disease. Okay, second, stereopsis. You know, we show them the circles to show them, you know, the animals. But, and this is something new to me, but there is, you know, a paper actually that correlates, you know, the circles, how much one could see with circles with visual acuity. So for example, nine out of nine circles is approximated to 20-20 vision. Six out of seven or five out of nine circles, I can see there, about 20-70 vision. So again, remember that stereopsis is a binocular function. This is not a monocular function. So some stereopsis may suggest that one may be seeing a little better. So again, these are not, these are, these are tests. These are not, this is not proof that they have a non-organic disease but this can have a, suggest that somebody has non-organic disease. Second thing is a size consistency test, you know, are cell-encharged and at least in our, in our clinics it's in the TV and they're at 20 feet. But if you move it to 10, you know, if you have a manual cell-encharged, if you move the patient closer to about 10 feet, the patient should be able to read the letters, at least half the size of the letters that they can at full distance. So that's easy to do in most other clinics, you know, Fort Street clinic, we have that. So I think these are all good, easy tests as well. All right, now visual field defects. I have some cases for you guys, so pay attention. So let's see, it doesn't show one by one. I'll just kind of say this. So this is a 12-year-old girl. This is a real case. I got it from this paper. But a 12-year-old girl that's, you know, all of a sudden presented with left temporal visual field defect, you know, went to an outside optometrist, got a visual field and showed, you know, the top, the top figure right there. And then went to an ophthalmologist and also did a visual field and also had this test. They got an MRI, it was normal, you know, and then went to, you know, this neurophthalmologist, all tests were normal. There was no APD, vision was 2020. They did, so in figure C, you see that left temporal defect in the left eye. And then they did a manual, like a Goldman visual field test and also show that it matches up. But the neurophthalmologist, what they've done is they've repeated the Humphrey visual test with both eyes open and so saw the defect up above. Okay, so, so, so, so, and again, you know, the third line, persistence of hemianopsia during binocular visual field testing. And without an APD, distinguishes this from an organic, ideologies are non-organic. So if you have both eyes open, one of the eyes, the right eye, should be able to compensate for the temporal defect. And still she was not, she was still having this dense defect. So this is an example of how an automated primary like Humphrey visual field testing that we have here can show, can support a non-organic visual field defect. Also non-organic visual field loss occurs in about one to 5% of pediatric patients in general ophthalmology. So it's not, it's not, it's not rare. Other tests that we can do for non-organic are confrontation visual fields. So, you know, we all do this, but when you're doing this, what you can do is map out where the, if it's a dense visual field defect that a patient says, you know, really map it out. Let's say it's in this area. Can you see this? No. Can you see this? No, no. So in your head, you've already kind of mapped this area out and then, you know, do your tests and then all of a sudden tell them, you know, I'm gonna test your, you know, your motility. So your saccades, you know, can you look at my nose? Can you look my thumb? All right, look at my nose, look at my thumb. Great, look at my nose, look at my thumb in the area of the visual field. If they have correct saccades, that's just that they can see in that area. That's another way to say that they, that it's non-organic. The second test is the kind of, again, counting fingers, telling them, you know, can you see, tell you none if they don't see fingers. So, see fingers here? No, or can you see fingers? Yes, two, two, and then you go here and they say none. Okay, so that suggests that they also see, seeing in that area. So these are easy tests to do in the clinic. All right, my first case, I'm sorry, it's not going one by one, but who has non-organic visual field loss? A or B? So in A, this is the tangent screen test. A, the top pictures are at one meter, and the bottom picture is in two meters. Who has a non-organic, likely non-organic visual loss? A or B? A, okay, so let me talk about the tangent screen. For those of you who have not done this. So the tangent screen you test at one, I'm sorry, not one millimeter, that's one meter. So one, one meter. So in the top panel, patient sees one meter, and then you map out how, you know, they're basically their visual field. And when they go from one meter to two meter, that field should expand. And you can see that in figure B, that the visual field expands. If it doesn't expand, or what is called a tubular or a gun barrel field, like it just stays like that, you know, people with non-organic visual field says, you know, they don't know that normally it expands, so they must see where they saw before and just remain there. So if it's a tubular or gun barrel field, that suggests a non-organic visual field. This is a test that we do quite often in the neurophymology clinic, pretty easy to do as well. All right, case, what visual field suggests a non-organic visual field loss? Anybody? And you know, this is, you know, for at least in this chapter, you know, this is, I'll talk more about this because this is actually in the old caps. So anybody can guess? This is sort of a trick. Yeah, first one, correct. All of them, okay. So let's go all of them. We know why all of them are non-organic. This is classic for OCAP. So the first, the one on top left is, you know, a spiraling isopters. That when you can see some spiraling, but also most important is crossing. And the third one is a study that I found is called a target visual field. So for the ones that haven't rotated neurophymology, let me just go over Goldman visual field testing. So, you know, there's several stimuli for Goldman visual field. So the size goes from zero to five, zero is the smallest, five is the largest. So this is a target size, okay? So it's a light. Intensity goes one to four, one is the dimus, four is the brightest. Intensity is A to E, A is the dimus, E is the brightest. So in this example, the blue is one, four, okay? So it's a small size, intensity four. And then in the red one is, I think, a five, four. So it's a one, three, okay? But the point is the red one has a larger size than the smaller one. So as the stimuli is getting larger, you know, you should be able to have it, you know, a larger area that you can see, okay? So this is normal, okay? So, and again, you know, just I just want to make sure that everybody understands this, but when somebody's, you know, when somebody's like, to draw the circle, it's not really a circle, somebody points, you know, can you see this, this, no, no, no, no. And then when they hit this and they put an X and that's the place where somebody's seeing it. So that's a point in here. And then there's multiple points and they just connect that dots to make that circle, okay? So in the first case, we have spiraling. So in spiraling, so concentrate on the red one first. So with the same stimuli, you know, as the test progresses, okay? So somebody can see first maybe outside in top line. And then when you go to this, when you go here, they say, oh, and now it's a little bit more constricted. And then when somebody is looking, and then the next, the third point is here. So it becomes progressively smaller and smaller. So that becomes why it spirals, okay? And then you do the next, the next, you know, larger stimuli like the black one, and again, very similar. So a spiraling isopter suggests a non-organic visual field loss. The second one is the crossing isopters. So I've seen as the stimuli size gets larger, they shouldn't really cross each other. And in this case, you're seeing, you know, the green is crossing with a blue and that suggests a non-organic visual field loss. The last visual field test and these two things, I've seen this in some questions for OCAPs. That's why I'm, and sometimes when I first saw this, you know, you can memorize it, but you know, I want you to understand it really. And then the last thing is this target visual field. So as you can see, there are, you know, several colors, red, blue and green. The protocol for this, so this was published in 2010, is that they started with a size 3, 4 E. So they go to, so they map out the red first, okay? And then they go to a larger size 5, 4 E, which is the blue, which you can see already is a crossing over. So that suggests non-organic visual field loss already, but they do a repeat 3, 4 E again. And then once they repeat the stimuli, the first stimuli, they even get it even smaller than the first one, which doesn't make sense. It should be the same size as the red, but because the red, I'm sorry, this should be green. The red and the green should be the same, but it's not. So that's why it's called a target visual field. 91% of like 50 patients that they've had a previous diagnosis of non-organic visual loss had a target pattern, while no eyes in the control group showed a target pattern. And this is something that I've learned. We don't do this, but this can be done in 10 to 15 minutes and this is something maybe we can try as well. So those are, that's it.