My name is Jeff Weaver, and I want to give some credit where credit is due. This course was developed by myself and Gregory Good, OD, PhD, professor emeritus from The Ohio State University. We've both had leadership roles in the American Academy of Optometry's Public Health and Environmental Vision section, so I am an optometrist, don't hold that against me. Through the years, we've consulted on numerous projects related to vision requirements and vision testing, including contracts with Boeing, Department of Homeland Security, and projects related to visibility issues and lawsuits. So the intent of this course is to discuss vision issues and occupational testing so that those of you who are not primary eye care providers might be reminded of some of the details so that your testing results can be more accurate. So it's challenging in any presentation to know what each member of the audience already knows, so if anything is reviewed to you, please don't be insulted. I hope each of you can come out of this with a couple of clinical pearls that you can use. Okay, slide advance, not working, let's see if this does it, there we go. So we're going to cover these five areas, visual acuity, refractive error, color vision, depth perception, and visual field, because they're the most common visual attributes for which occupational vision standards are developed and routinely tested. So I hope to bring up some points that will help you in your occupational vision assessments. Probably the most common vision standards are related to some level of visual acuity, and usually these standards are written for corrected visual acuity, but sometimes uncorrected, especially for those roles where spectacle or contact lens corrections could be dislodged, such as in law enforcement. And visual acuity is the best measure that we have to measure a person's ability to see fine detail. Visual acuity is assessed in all states for driver's licensure, and is also tested to assure safety in the task of many occupations. So as you recall, when the visual acuity is reported as a fraction, as it usually is, such as 20-40, the first number is related to the eye-to-chart distance, so 20 feet, and the second is the smallest letter that one can read, so a 40-size letter at 20 feet, 20-40. Because we're not always testing at 20 feet, it's important to note that acuity is a measure of the visual angle. We can do testing at different distances, and the number is a relative term that helps us to know the eye's resolving ability. The classic measure has been a Snellen chart that you can see on the figure on this slide. It's been around since 1862. These charts are typically hung on a wall, tested at a distance of 10-20 feet. Any of you still using that particular chart? I hope we at least got rid of the serifs on the font. But the Snellen chart has some inherent problems. So with either chart, letters are not the same difficulty. What that means is if you use a Gaussian blur technique, or even a dioptric blur, some of these letters are going to be easier to identify than others. Like an O could be a D or a G, that one's a pretty tough one, an L, not too much else has the shape of an L, so you may be able to identify an L even with a lot of blur there. There's very few letters in large size. I've seen some where it's like 2200 minus one, where there's only one letter on a lot of these eye charts. Does that mean you missed it? So that's a problem. Unequal spacing between letters, that becomes a problem with tracking sometimes, if there's a tracking problem, not necessarily visual acuity. It's hard to precisely measure poor acuity. Is there really that much difference between 2400, 2800? Maybe not. So it really works better for more normal acuity, as in corrected visual acuity, down at the lower parts of the chart. And typically, we're guilty as this, as optometrists and ophthalmologists, we're not really interested so much in uncorrected visual acuity, because it's directly related to refractive error, so we may not even test that or test it very accurately, because we don't really care. Even though the patients ask us, what's my vision? Sorry, I'm pausing between this, because the online is just a little bit of a delay there. Note that the uncorrected visual acuity is correlated with refractive error. And as I said, we don't really care so much about uncorrected visual acuity. A lot of times, in a clinical examination, just as an eye examination in the office, it's usually only measured at the initial visit, and maybe then, only if the person doesn't come in wearing habitual glasses. The reduced uncorrected visual acuity is usually from refractive error, and it's correlated. And that is important. When we're doing medical review, we look at this correlation. For instance, an example might be an individual who's determined to have five diopters of myopia, or refractive error minus five. So the far point, if you do the math, the furthest that this person can see clearly is 100 over five, or 20 centimeters, which is about eight inches. Some of you can relate to this. So there's no way this person has an uncorrected visual acuity at 20, 70. You don't see this a lot. And that may be related to the fact that, I don't know how many of you have seen the study that the high percentage, unfortunately, of providers that will, let's say, help a patient to get their job, and, oh, what do you need, 20, 70? Okay. We got you here. I got you covered, buddy. And that's not really in the best interest of the individual, for their safety, or for the public that we're trying to protect with these vision standards. So when uncorrected visual acuity is tested, the instructions given to the patient are typically, you know, what's the smallest line you can read? The patient will often say, you know, depending on their personality, whether type A or type B personality, but they'll often say, oh, they're all blurry. Oh, okay. Well, then, can you read the, can you see the top letter? Yeah, it's an E. Okay, 2,400. And again, we don't really care so much, so unless we're paying attention and we know that the uncorrected is important for something like a vision standard, then testing's done. And then we might go back and question that after we see the refractive error, but that may be what's already in the EHR. Because it's really not valued by the doctor. It's done as quickly as possible, and it's a problem when there are uncorrected vision standards. Yes, sir. Do I need to level you? Okay. I was wondering about that. Thank you. So an alternative that might be a better technique could be this. Read the first letter in each row. This may not stop them from reading right to left. I'm not sure why they do that sometimes. Have you ever noticed that? You don't read right to left normally. Why are you doing it on my eye chart? But read the first letter in the row, and go down, and then stop when they miss one. Have them go up one row, then read all the way across, and see how many they get there. They get more than half of the letters, go on to the next row, and keep going until fewer than half of the letters are read correctly. The more modern acuity charts that I hope everyone's using are log-mar charts. That is the logarithm of the minimum angle of resolution. So as you may know, a 20-20 letter subtends five minutes of arc overall, with critical detail subtending one minute of arc. So that critical detail being the letter stroke width of a C, the opening there, the gap in the C. So a 20-20 letter has a minimum angle of resolution of one minute of arc. So the original log-mar charts, as you see here, were designed by Ian Bailey and Janet Levy Kitchen in the mid-1970s. They became popular first with the ETDRS chart that was used first in the early treatment diabetic retinopathy study, starting in the early 1980s. And if you note the differences there between that and the Snellen chart, there is, instead of an irregular progression of acuities, it's a logarithmic progression. So the difference between the rows sort of makes sense. Where on a Snellen chart, you go from 20 to 25 to 30 to 40, back to 10 difference of 50. There was really no rhyme or reason of doing that. There's the same number of letters in each row, so you know if someone misses, it gets a 20-20 minus two, you know that's two out of five. And there's an equal difficulty of letters throughout the chart. So talking about that blur out issue that I mentioned, these all have very similar blur. That L that I mentioned, which is pretty recognizable, you won't find that in a log-mar chart. So if a patient has good distance acuity, then near acuity should be expected if the appropriate near correction is worn. So even with somebody who is an absolute presbyope, 65 and older, has no focusing ability whatsoever, if you can get them to 20-20 at distance, you should be able to get them to 20-20 at near with a plus 250 add very easily. So for many occupations, specifically designed near glasses may be needed to provide sharp vision at various angles and distances. And that depends on the specific job task that, you know, one can think about overhead monitors of a pilot that may need, instead of having the near correction at the bottom, they may need near correction at the top or intermediate correction at the top as well. Near visual acuity charts are often just reduced letters like the distance charts, but functional acuity charts that use sentences, such as the example I've given you here, are often more useful because that's what a person is doing at near. The other figure here is just to remind you of the importance of good visual ergonomics and overall ergonomics, especially when doing near work for long periods of time. All right, let's move on to refractive error. This is a good transition from visual acuity because the most common reason for reduced visual acuity is uncorrected refractive error. And as we mentioned, it is correlated. More on that in a bit. So for a review of refractive error, remember that a diopter is an inverse meter. So a one diopter lens focuses at one meter, so a person who's nearsighted and can see clearly only up to one meter away requires a minus one diopter lens for clear vision at that distance. They're a one diopter myopia. Myopia requires minus powers, hyperopia requires plus powers for correction. For the definition that patients always ask us, stigma means point, referring to astigmatism here. If a person's refractive error is such that it does not focus at one point, then they are diagnosed with astigmatism. So this is concerning to most to hear the word. Sounds scary, doesn't it? Oh, you know, and a lot of them will come in, I duck, you know, I want you to know I have astigmatism. Oh, good. You and 90% of the population. So don't worry about it. Sometimes it's not terribly clinically significant, but a lot of people have it. So we often use a football analogy to describe this, but that can really be misleading. So the reason it is misleading, and I tend not to use it, is if you use a football, people are thinking that their eye is pointy, and that's not astigmatism, that's keratoconus. But it can be a football when you hold it by the tips here, where one meridian is more steep than the other. But you have to point that out or actually get a football out and explain it that way. But it's when the front of the eye is not a perfect sphere like a basketball, but more curved in one direction than the other. The football can really be at any angle, but most often it's either horizontal or vertical. And with the rule of astigmatism, and sometimes we think about the percentages that they use with the rule may not be with the rule anymore in 2022, but that's what it was termed. And with the rule of astigmatism, a horizontal type of astigmatism, the football is horizontal, like I was holding it by the tip, more power vertically and less power horizontally. Horizontal lines are more blurred. Against the rule of astigmatism, football is vertical, more power horizontally, vertical lines are more blurred. So oftentimes I'll use the plus sign explanation instead of the football one, and that is if you're looking at a plus sign and you don't have any astigmatism, but you have nearsightedness or myopia, the plus sign focuses here, it focuses together, and we have to move that back onto your retina. If you have astigmatism, the vertical line focuses here, horizontal line focuses here, so if we're just correcting that myopia, you still have this blur between these two images. So if you want your astigmatism corrected, and I want your astigmatism corrected, we got to pull those together. All right. So in a prescription, the amount of astigmatism is the second number, and the location of the astigmatism is the third number. So this can be recorded in two different but equivalent ways. Now you wouldn't think those two powers that you see on the screen there are equivalent, but they are. The first one perhaps written by an optometrist because eyeglasses are manufactured in minus cylinder form, so we usually use a minus cylinder format. Ophthalmologists tend to use a plus cylinder format because it's more useful in some of their calculations for cataract surgery, for instance. One means of assessing a relative amount of refractive error using just a single number regardless of the amount of astigmatism is the use of spherical equivalent. So if you want to calculate that, it's just the spherical amount, the first number, half of the astigmatism number, and add those together. So that gives you a pretty good idea of the overall resolving ability of the eye based on refractive error. But while spherical equivalent is useful, the location of the astigmatism is still important when assessing uncorrected visual acuity. So even for individuals with equal spherical equivalent, a person with the role of astigmatism can usually see a little bit better because squinting the eye just slightly improves the vision more than it would with against the role of astigmatism. So you may have some variations there. I'm going to give you a little bit more sophisticated representation here of that correlation. So this was just done in a recent study that was published a couple years ago of the correlation between visual acuity and refractive error. So this is a box and whisker plot of refractive error as a function of visual acuity. Refractive error is a function of visual acuity. We've added a couple of visual acuity lines that can be used for comparison. And one of the important ones is 2,200, 2,100, which is the pretty common uncorrected visual acuity in law enforcement. So if you look at the amount of myopia, if you can read that, on the bottom, on the x-axis there, the far left, at the origin, that is pretty much the limit of 2,100 there with that line going across. So anybody that has a refractive error of greater than about three diopters of myopia, spherical equivalent, is very unlikely to have any better than 2,100 visual acuity. So again, if you see your law enforcement candidates perhaps coming in and they're in that minus five, minus six range and they're 2,100, not really likely. So something's going on here. We need to investigate this further. All right. So next area is color vision. Trivia test fact of the day. I put this in for you guys. What is the most common single locus genetic disorder in humans? That's red-green color vision deficiency. So I'm not sure color vision deficients want to know that they have a genetic disorder, but they do. So you can categorize color vision deficiencies in numerous ways. And one way is differentiating congenital versus acquired deficiencies. Congenital color vision deficiencies are typically present from birth by definition. They're stable. They're bilaterally symmetrical or pretty close to it. They affect the entire field of vision versus acquired deficiencies that by being acquired, there's some progression and they can regress later. More often than not, they're going to be one eye only or at least asymmetric. They can affect only a portion of the visual field. If it's a, as a matter of fact, macular degeneration, one of the indicators in that can be color vision deficiencies that's only affecting the macula. And then many other conditions that we see on a regular basis, cataract, glaucoma, diabetic retinopathy, optic neuritis, and certain medications can cause acquired defects. So another way of categorizing color deficiency is by the number of cone receptors. So normally individuals have three cone types and having fewer or anomalous cones causes a deficiency. So this list is an order of worst to better color discrimination and it should make sense. So those with the worst color deficiency are monochromats because they have either no cones in the terms of rod monochromats or cone monochromats have rods in one cone type. So pretty rare, but very color deficient. Those with two cone types or dichromats are more common, still relatively severe. And then those with milder color deficiencies have three cone types, but the cones have properties that are different than normal, so-called anomalous trichromats. Okay, another quiz question. So which of the following color vision deficiencies is most likely to be encountered? Protanopia, deuteranopia, protanomaly, or deuteranomaly? Well, it is. Did it advance? Did not advance. No, it did. Well, it was deuteranomaly. It didn't, I don't think it advanced on, as it should have there. But, and it's not even really close. So, if you look at the, and most of these studies have been Caucasian populations. These go back a lot of years. But if you look at a total of males, about 8%, females about 4 tenths of a percent, but the deuteranomalous individuals, so they have a deutan defect affecting the middle wavelength or green cone, if you will. But it's still there, it's just not in the place normal for humans. Almost 5% of the 8%. So, very common. And they are X-linked, that's why the female is roughly the square of the male percentages. You don't see too many female color deficients. But, as I said, the classic studies are in Caucasian populations. Just about every other population has fewer, but it's not insignificant. It's still in that 4% to 5% range of males that have color deficiency. And just as a reminder, here's the peak sensitivities of the photoreceptors. 420, the short wavelength or blue cones, are at 420 nanometers. The rods, peak wavelength of about 498. The medium wavelength cones, or the green cones, at 534. And the long wavelength cones, the red cones, at 564 nanometers. So I hope this advances well, because I want to show you a simplified demonstration of what we classically understood to explain the variations in the degree of color deficiencies. So here we have the short, middle, and long wavelength cone absorption curves of a normal trichromat. So, if any of the curves' peak absorption in an individual is shifted, that would signify an anomalous trichromat. So if it was shifted just slightly, there'd be only a very mild defect. If it shifted further, color discrimination's getting worse and worse and worse until, what do we have there? A deuteranote. So that's how that very common deuteranomalous individual, you know, further and further shifting would be, you know, if you had individuals along the line there, along the spectrum, would give worse deficiencies. So that has been the classic explanation. We now have a little more research that's refuted this understanding. This next slide goes a little bit beyond where I wanted to go with this, but there's not really just a single normal absorption curve there's classes of photopigments that have normal variability. So, you can see the L-class or the long wavelength cones and the different classifications they have. There's this number of different plots that are still considered relatively normal. In the M-class, not quite as much variation, but there are some as well. And so that's because there's a normal variability in the amino acid sequences of the LNM pigments. And that creates this variability in the absorption spectra. The bottom portion of this figure, really going beyond where I wanna go. If there's any geneticist wants to come up and explain this better than I can, please do so. But the LNM ops and genes have six exons and they found that exon five encodes the amino acids involved in the spectral tuning. So, exon five on the X chromosome is responsible for the majority of the spectral difference between the LNM pigments. So, yeah, I think that's all I have to say about that. So, I think the exciting development in the research coming out of the genetic testing and Jay Knight's and others is that there may be a treatment for color vision deficiency in the future. Now, a lot of our color deficients think there's treatment for it already. They wear their X-chrome contact lens in one eye or they spend $800,000 for these glasses that are designed to help them see. And they're not. They spend $800,000 for these glasses that supposedly correct color vision deficiencies that do not work. They may help in color naming a bit, but in terms of function and safety for what we're looking at on the job, they do not work. So, what they've been doing on monkeys at this point is injecting genetic material into monkeys that are missing the L gene or have protanopia, and they're able to discriminate colors in the red and green range from each other and is different than gray. So, there is a promise that sometime in the future we'll be able to treat color deficiency. So, as we move towards discussing function, I would like to remind everyone that individuals are not color blind. Well, maybe a few of them are, but most of them are color deficient, and we should use that terminology. So, only the rare individuals who are rod monochromats are color blind, and that's no cones whatsoever, because each cone type can detect 100 gradations of color. So, even a cone monochromat, an individual that has rods and one cone type can distinguish 100 shades of color. A dichromat, so a person that has pretty severe color deficiency by our standards, still sees 100 times 100 or 1,000 shades of color. And a trichromat, even an anomalous trichromat can distinguish 1,000, I'm sorry, 1,000,000 colors. So, a normal human can distinguish 1,000,000 colors. That's a lot of crayons. I do wanna mention an interesting variation in the other direction. There are a few people out there who, in our simplistic explanation, have four cone types. So, they have the ability to distinguish 100,000,000 colors. And one of these people happens to be an artist, and she paints the world differently than anyone else that I've ever seen. So, I encourage you to check out her fascinating website at concettaantico.com. I have no financial incentive to say that other than it's pretty neat. It looks like she either has some color division enhancement or she's tripping on LSD. So, why is color division important to us? Well, there's a few reasons. First, and perhaps most important for us in occupational concerns, is that it codes and transmits a message. So, it's become innate in us, in all of us, when we look at a traffic light, to know that red means stop, green means go, and yellow means go real fast, or perhaps caution, depending on whether or not we're late for work. But second, it organizes the information and it organizes complex visual displays. So, it'd be very difficult for sports teams, for instance, especially at the collegiate and professional level, if everyone were wearing different clothing. So, as it is, we know whether the player around us is friend or foe or a referee, depending on the color of the jersey. And finally, maybe less important, but it evokes an appropriate mood or emotion. There's some colors that are more aesthetically pleasing than others, probably why only teenagers have bedrooms that are painted black or dark purple. An example of this, related to both coding and organizing complex displays, is the deck of a U.S. Navy aircraft carrier. There may not be a more hectic place to work, but to manage that craziness that's going on there, each job type has a specific color code, which is especially important in an environment that is not only visually demanding, but where noise makes verbal communication impossible. So, I wanna do a demonstration to prove to you that coding by color is beneficial. So, I'm gonna show you a slide. Slide has squares, circles, diamonds, and triangles, kinda like Lucky Charms, I suppose. And when I show you the slide, I want you to count the number of triangles. And the bonus is to count the number of circles. So, I hope the timings are set up on this, so it'll go automatically. If not, it's gonna not prove my point. But let's see if it will, because you only have one second to count if it goes automatically like it should. Okay, ready? You're looking for triangles, and for you gunners in the room, you're looking for circles. Okay. Good, the timing worked. Okay, anybody get that? Back of the room, it's gonna be tough. Anybody in the front of the room? Remember, how many triangles? At least one. At least one? One. Very good, that's a safe bet. Anybody get any other answer than that? Four. Five, four? Five. Five? Okay, so not a lot of consensus here. How about circles? Any gunners? At least one. At least one. Another vote for at least one. Okay, so I'm not gonna tell you yet, but remember those numbers that you thought you had there. Okay. All right, so now I'm gonna show you another slide. Now that we know the timing works, this will be good. And these are all diamonds, but they're coded red, green, blue, and yellow. So when the slide is shown, I want you to count the number of red diamonds, and those of you gunners go for the number of yellow diamonds So on this one, you want, first you want red, and for bonus points, you want yellow. You can have a full second. Here we go. So what do you think, in general? Okay, so here's the answers. On the first one, six triangles, two circles, so the lady greater than one in each, yes, she wins. But what did I do here? Watch the slide, watch the transition here. So exact same location, but one was coded just by shape, the second one coded for color. Even if you were wrong on both, wasn't the second one somewhat easier, faster to distinguish than was the ones just coded by shape? Coded by shape. So that's the difference that between a person who's fully color normal versus color deficient can make in terms of safety, especially if timing and speed is important. The reaction time can be significantly different. All right, so we have several different types of color discrimination testing. Importantly, no matter what test we choose, it's important to administer the test using the proper light sources and to follow the testing instructions. I skipped a slide, can I go back? I don't know that I can go back. Maybe I can. All right, that's the one I want. No, I went back too many. No, that's it. Okay, so we have several different types and I did wanna go to the next one. All right, so the type lighting that we use for color vision testing is important to ensure that the proper colors are represented by the test we're using. And proper lighting used for color testing is described as Northern Daylight. So the best test for color vision plates right now is to take those plates, go outside, we're in Northern Daylight, and that would be appropriate. But we want, in general, for artificial lighting, for the corrected color temperature to be greater than 5,000 degrees Kelvin. And with a good color rendering index, typically greater than 90. 100 is perfect, but greater than 90 is great. So this ensures a light source encompassing the entire visible spectrum with a color of white similar to daylight. Yeah, there are a few bulbs out here like the Ott Light Clear Sun that do that. Otherwise, just go to your Lowe's or Home Depot and read the boxes. They do have these numbers on them, especially the ones that are good, that have high numbers there. So color plates, how close do we hold color plates? A lot of times we think we hold them right at the near point, 40 centimeters, 16 inches. No, they really ought to be held out about 30 inches. And the patients allowed three seconds to respond. You don't let them look at it all day. So you get three seconds to respond. Remember, lighting's critical. And the Ishihara plates, as we used here, the most common pseudo-isochromatics to be used to test red-green color vision. And there's different plates here included in the 14-plate edition that you may use. There's a demonstration plate. If a person can't see that demonstration plate, they're malingering because there are luminous clues to that one. The brightness on the numbers is significantly higher than the background. So you can be even a broad monochromat potentially and see that there is a 12 there. So, but that is to kind of check for malingering is why that plate is on there and is on any of the tests. Plates two through 10 are the basic test plates on the Ishihara. 12 and 13 are diagnostic plates that are used, that can be used for those failing the initial test. And you can also distinguish between pro-tan and do-tan defects on those two plates. And they also have the couple of diagnostic plates there that have tracing. So, but the temptation is to let them trace it with their finger and you don't want them touching it. Otherwise there'll be a permanent sweat stain that everybody else following them will be able to see. Here's an example of that tracing one, the illiterate plate, if you will. And, yeah, most of these tests are done to take away some error in interpretation by just having everyone do all the plates and then an individual, one individual's interpreting the results on all the plates. The figure here is the HRR Hardy Rand Rittler, fourth edition, to which many agencies are moving. All color plates, whether using Ishihara or the HRR, are designed to have very high sensitivity and specificity. So I'm not sure there's any test out there that has higher numbers because really done properly, very close to 100% of color vision normals are gonna pass, 100% of color vision deficients are gonna fail. Yeah, I know it's not 100%, but it's really close and done properly, it really approaches that. The HRR fourth edition is very highly recommended and it will produce results equivalent to or better than the Ishihara when done properly. It can help eliminate cheating or memorization since we can rotate, you can see they're not numbers, they're figures on there, there's O's, X's, triangles. So you can rotate the test to four different presentation views and to make sure that they're not just memorizing it, because it's pretty easy to memorize these days. And again on those, there's 24 plates. Most agencies have, you do all 24. And look at the results after that. On the HRR, to give you a little more detail, there's four demo plates instead of just the one like there is on the Ishihara. There are six test plates. And then there are three different variations of diagnostic plates. All the plates from 11 through 24, as a matter of fact, are all diagnostic and they can not only tell you the type of deficiency, whether it's a PROTAN, a DUTAN, or TRITAN even, but it also tells you the severity, whether it's a mild, moderate, or severe color deficiency. So it's a really nice test. All right. I must keep hitting the button here. Okay. Okay, here we go. So arrangement tests, and you've seen some of these. This is, in this picture is a Farnsworth D15. And what's the D stand for? Dichotomize. The Farnsworth D15 dichotomizes color vision deficiency. A lot of times you'll see this, passes Farnsworth D15, color normal. No, if they're doing a D15, shouldn't even be doing a D15 unless you've done plates to determine whether they're color vision deficient and they can move on to this. What a Farnsworth D15 test will do is dichotomize the level of deficiency. So it's gonna pass 50% of defectives. So those with the most severe color deficiencies are gonna fail a Farnsworth D15. Those with mild to moderate will pass. So the other one, there's also a desaturated or lanthony desaturated D15, which has the same hues as the Farnsworth D15, but they're desaturated. They're a lot harder to see. If you can pass with a lanthony desaturated D15, you only have a mild deficiency. The other test you may be aware of is a Farnsworth Munsell 100 hue, FM 100 test. It's really used for fine color discrimination. And there's no real pass fail criteria on that one, but most individuals with normal color vision have a score of 80 or less, 80 errors. It's very, very difficult. So on these arrangement tests, if you're administering them, there's no specific time limit, but most people that have either color vision, normal or mild defectives can complete this within two minutes. They shouldn't be in there for a half an hour. I guess the most important thing that I say they shouldn't be in there, they shouldn't be alone anyway, because they need to be monitored for a number of things, make sure they're not just flipping over and looking at the numbers and putting them in that way, or perhaps just taking a long time to do it, and knowing the wrong way from their point of view that they're looking at them and can place them that way because this is the way the doctor wants so I can get my job. So if they're doing it that way, if they're treating it that way, they're seeing it not correctly but what they see, but what they have learned the different caps and sequence are supposed to look like. So, trick question, how many caps in an FM 100 test? There's not 100, there's only 85. Why it's not the FM 85, no one knows. Well, Farnsworth and Munsell might know. But, so here's something to watch for too, especially in the online test. So many of these tests you can get online, some of them are okay, but a lot of them are not. And I think you lose, especially if they're not taking them while you're watching them very closely. And I'll give you an example of why that is. A master gemologist appraiser, so those are gonna see how much you're gonna pay for the engagement ring guys. They have to pass an FM 100 with an error score of 25 or better to keep your master gemologist credential. Well, so 25, I said 80 or better is for most color normals. 25 for master gemologists. And one individual that I was reviewing, he failed the plates, so he has a color deficiency. And he failed the Farnsworth D15, so he's got moderate, maybe severe color vision deficiency. He goes and takes the online versions of these from someone, passes a D15, no errors. He passes the FM 100, zero error score. So not only this guy probably can't get into a lot of law enforcement positions, but he can be a master gemologist according to the online tests. So I said that this is wrong, that this is invalid. We need to retest him on something else. So be careful on color vision deficiencies. That 8% of males out there, they can game the system. And if they've tested poorly in the past and you see them coming back years later and their color vision testing numbers are better or miraculously better, not likely, not possible. What they've probably done is they've gone onto Amazon, bought some of these, oh, it's an Ishihara, I can memorize these plates. They're gonna give them to me in the same order every time. Or they'll buy a D15 and practice. And let's see, this is what it's supposed to look like. Okay, I can remember to put it in that order. So the system can be gamed. All right, now let's get into more practical applications of color vision. Pilot is one occupation for which good color vision is important. So looking at this aircraft, is this a modern aircraft or an older aircraft? What do you think? I heard both answers out there. Well, that's probably correct. Does anybody know what this is? This is a Concorde. So kind of a trick question, very sophisticated aircraft, right? But Concorde first flew in 1969. But you can see on this a lot of white on black gauges, not a lot of color tasks in the cockpit. Compared to a modern glass cockpit, that uses a lot more color. The stuff outside is more for effect. But if you look at the gauges themselves, a lot of color related, color important tasks there in the cockpit. So one of the acceptable alternative tasks for FAA color vision testing is a Farnsworth Lantern or Phalanx. So the Phalanx simulates the signal light gun test that's used to signal planes from the control tower. They still use those. And presentation is a series of two lights that are either red, green, or white. And there's nine presentations of these. If you think that thing looks like a dinosaur and you probably can't get one anymore other than military surplus, you're right. This is a more modern version, Optech 900. Looks a little bit more modern, certainly much lighter, but it has the same presentation. Actually, I own three Farnsworth Lanterns. I went on to surplus site, bid on three of them thinking I'll get one of them. I can't believe there weren't multiple people trying to bid against me. I got all three of them. My wife loves them. All right, so if you've ever watched outside when you're landing in a plane, you're gonna notice a series of lights along the edge of the runway. These are precision approach path indicators, or PAPI lights, which is a series of four horizontal lights. Pilots look at the incremental guide to determine whether they're on the correct glide path for landing. Four white lights means you're way too high. Four reds, you're way too low. Ideal glide path is two whites, two reds, and then the three and ones is you're kind of in between. You need to move just a little bit up or down. Back in 2002, this became a problem because there was a FedEx plane that crashed upon landing in Tallahassee, Florida. And the story on this is that the first officer told the captain that the PAPI lights were four white, so he's way too high, needs to go lower. So upon adjusting and going lower, the plane crashed short of the runway. Both individuals, it's a FedEx plane, there weren't passengers on board, but both of them lived, so further testing was available, and it was revealed that the first officer had a severe deuteranomaly. He still had anomalous trichromacy, so he had three cone types, but it was a severe deuteranomaly so that in my classic presentation, that green cone had moved very, very close to the red. So with color vision testing failed every test except for the Farnsworth lantern and the signal light gun. So the National Transportation Safety Board recommended research on the effectiveness of the FAA color test, not just the phalant, but all of them. So what did they do? 20 years later, phalant remains on the FAA list of acceptable color vision tests. However, it has been eliminated as protocol for NASA, Air Force, and Navy. And it was important for the Navy because as heavy as that sucker is, it also worked as a boat anchor for an aircraft carrier. So that was a big move for the Navy. So is anything gonna be done on this? Doesn't look like it. All right, let's go into depth perception. So what is depth perception? Well, it's the ability to perceive depth, and you can do this just with one eye with things such as parallax and certainly at far distances. But for that elegant sense of depth to see a very fine ball of your surface irregularity, you really need two eyes for that. And that's just not depth perception, that is stereopsis. With the eyes aligned and no monocular suppression, you're looking at a specific object from two different directions, and that's how you're able to do that. So that for practical purposes, particularly in law enforcement, which is what I deal with mostly, you can see hidden weapons of a person holding a weapon in their pocket or something, other contraband that they may be trying to hide on themselves or on vehicles, and helping to sort out the fine detail, you're telling whether a person's really holding a weapon or whether they're holding something else and whether you should take action against that person. So the depth perception testing that we can do it near is stereopsis, and it is produced by binocular disparity. Do we have binocular disparity for distant objects? Well, it really kind of depends on the distance. And I mentioned some of those monocular clues to depth. There's a lot of them. I'm not gonna go through all of these, but certainly motion parallax is probably the most common one that we notice. I can tell you guys are further away than my finger because of the way that you're moving relative to my finger. And even such things as accommodation, we get some clues from how much we're focusing and how much our lens is changing there. So there's a lot of monocular clues that we get that we can often get even really just from one eye, but there's certainly some binocular input to that. It's just how far, what is that distance where there's no more binocular input and it's equal monocularly. Might be a good study. Surprise, it's never been done. Actually, it's tried to be done, but there's a lot of questions as to what that distance really is. What is true infinity as far as stereopsis goes, I suppose. The best test of stereoacuity have both a test of global and local stereopsis. And I put all the notes here for you guys to read because it's a little tricky. So global stereoacuity, and that's what you're gonna get from those tests on the right, where it looks like just a bunch of random dots and that's what they are, it's called random dot. You're getting a larger area disparity and you have to get a large area of the retina inputting to that so that you can see the hidden image in there and have that perception of depth from that. Now the local stereoacuity that you get from the circles, the word circles, you're gonna get that from a small area of the retina from each eye. So that's the difference between local and global stereopsis. If you've wondered on a forum, we'd like local and global, that doesn't mean, I've had some people say, this is what their local means, near, global means far. No, it doesn't, that's a totally different concept here. But if you've ever looked at any of those word circles, the local stereopsis, even without the cross polaroid, 3D glasses, if you will, on, you can see the little offset of those circles that creates the disparity that makes it look like it's standing up closer to you, like a button you could push down on. And so even a person that has monocular vision, totally no light perception in one eye, if you're not putting on the cross polaroid glasses, they can probably see a couple of those. Matter of fact, of all places, Fort Rucker, Alabama, at the home of Army Aviation, there was a, fortunately not a pilot, but I was down there doing, back when I was wearing the uniform, not a pilot, but some other individual that had a stereopsis requirement, you know, he puts on the cross polaroids and he can't see, he goes, I'm gonna take these off, I can do better. It's like, no, you can't do that. He goes, oh yeah, they always let me do whichever one's better. It's like, at USARO, at home of Army Aviation, they're doing that, that then validates. You need to have that on because, go ahead and take a look at it yourself when you get back there, just close one eye and you'll still see that offset. Or don't put on the glasses, you'll still see the offset. So other things important, small angle strabismic. So if somebody has a microtropia, it's really hard to see these things. I mean, you can do a cover test on them and see absolutely no movement, but they are still, they do not have bifovial fixation. So they are a small angle strabismic. They can actually show local stereopsis, but they will not get through that global stereopsis. So they'll be able to do some of the word circles, maybe down even to a passing, what's passing on most of our, a lot of our jobs require that, 70 seconds of stereopsis. They may be able to get 70, but they won't be able to get global at all. And it's an easy one to miss. And it may be a reason that we ought to do global stereopsis more often. The other thing that's interesting is longstanding uncorrected astigmatism. And unfortunately, there's a lot of people out there that have longstanding uncorrected astigmatism. I'm not sure why, but someone's missed them. They do pretty poorly on these stereocuity tests, but in real life tasks with the corrected astigmatism, they do pretty well. And then if you bring them back to do the stereo test, years later, they're going to improve on that. Much like amblyopia improves over time with wear of correction in many cases. Okay, so there's some auxiliary binocular vision tests you might like to know about. And this one is the Worth 4-Dot, affectionately known in school as the worthless 4-Dot, but it is a Worth 4-Dot. And it really tests depression and double vision. It's also another test of a binocularity that might be helpful for these individuals where they have questionable stereocuity results. And it can test suppression of one eye and a tendency for diplopia as well. Should be tested under both light and dark conditions. And why is that? In darkness, there's fewer cues to help with fusion. So all you have is this light source and there's no peripheral retinal input to help fuse the objects for you. And it should be tested with a white light down. So red on top, white down, and the greens on the side. So if you're holding it that direction, there could be five results. And if the person says, I just see two reds, they're suppressing the left eye. They see three greens, they're suppressing the right eye. And then five lights, they are not fusing. So they have diplopia, either esotropia or exotropia. And four lights means normal fusion. And sometimes you can even tease out the dominant eye here by saying, where do you see three greens and one red or do you see two and two? Another airplane crash. This one did have passengers on board. Fortunately, nobody was killed. But another one related to vision that I wanted to bring up to you. So this was a Delta Airlines, McDonnell Douglas, MD-88, no longer flying. I flew that plane a lot. I'm sure a lot of you flew that a lot. At least not flying on American Airlines. I don't think anybody else is using them anymore either. But it was coming in for an approach in LaGuardia. Has anyone looked out the window in LaGuardia? I don't know how pilots land there anywhere. There's just, it's just so complex. And there's water around and everything. But they were landing, they struck the approach light system in the runway deck structures. And due to the impact, the main landing gear separated from the aircraft body. And that led to the sliding the aircraft down the runway on its fuselage belly, almost into Flushing Bay. So the NTSB determined the main cause of this was the captain's use of monovision contact lenses. So that's one eye corrected for distance, one eye corrected for near with contacts. And are monovision contact lenses allowed in pilots? No, and they never had been even before that. However, you talk to pilots, I would go to the air show at Oshkosh and we had a booth there, our aviation vision booth to talk to pilots about their problems. And if there was any eye care providers that came by to try to help them to learn more about how to take better care of their pilot patients. Well, the pilots would come by and say, don't tell the FAA, but the way that I function best is with my monovision contact lenses. They're like, yeah, really don't tell me that. You can't do that. That's not legal. Well, I have to do this. The NTSB said that, in their ruling, that the brain would be unable to fuse the disparate images causing degraded depth perception. So while monovision contact lenses were previously prohibited, the NTSB ruled that enforcement should be increased by optometric associations and airlines. And what the FAA did in response to that, if any of you fill out the 8500-8, the FAA form, right on the front page, do you wear contact lenses for near or monovision contact lenses for near? It seems like a pretty specific question for the first page of the FAA form, but that's what's on there now. And the optometric association certainly put that out there and I hope the airlines are enforcing that better as well. However, based on what we talked about earlier in the distances involved here, is that really, was it really stereopsis? Or was it just the conditions that whether the person's wearing two distance contact lenses or monovision is still gonna clip everything? I can't think that that was true stereopsis. It would have been, if anything, some of those monocular clues, the depth, that were hindered by the visibility. But as a matter of fact, American Optometric Association argued just that with the FAA and of course lost. But so we're trying to enforce that the best we can now. Okay, last but not least, visual field. Okay. So the human visual field is very extensive, even in non-moms. So each eye can see temporally about 100 degrees and nasally 60 degrees if looking straight ahead. So this yields a binocular visual field of 200 degrees with about 120 degrees of overlap. So interpreting a standard and reporting the extent of field can be tricky. Because have you ever seen like a reporting form that says visual field right and left? And sometimes you don't know whether that means, are you talking about the right field? Are you talking about the field of the right eye? And that's different. So if you run across a form that's unclear, make sure you know what they're really looking for. One note that Dr. Hartenbaum mentioned in her DOT lecture yesterday was the CDL requirement. And I'm sure most of you are familiar with that. Since 1970, that field of vision requirement has been 70 degrees in the horizontal meridian in each eye. Which is, to me, is a little bit scary the way it has been and I guess will be in the future. So the controversy has been, it's been discussed since it was first released and most notably by a panel of experts in 1991, that the original intent on that was 140 degrees binocular field. Which makes me feel a lot better about a semi-truck driver having 140 degrees binocular visual field. But once that recommendation, which was what it was, went actually into print, they said, well, we need each eye. So 140 divided by two is 70, it's 270 degrees in each eye and even at the time The experts said no, no, no, that's completely different. It went forward that way and and they won't change it So if you think 70 degrees in each eye if that's all overlapping, that's just a 70 degree field That's not a lot for somebody driving a weapon across the country So the recommended standard Has been it's been recommended to be restated as a field of at least 120 degrees in each eye measured separately in the horizontal meridian, but it has not been adopted by the Federal Highway Administration and If you listen to Dr. Hardenbaum's lecture yesterday It's not going to be why because now we've got all those years of precedent Where there has not been a cause like these plane crashes that has been attributed to this 70 degree visual field in each eye. So I Asked her specifically will they ever change this and she said no So it's like okay. That's what I thought I got from your lecture. I just wanted to be sure All right, so the standard for visual field testing is a Humphrey Zeiss perimeter and Screening Programs can determine the field limits temporally and nasally and it's important for individuals who have diseases known to impair visual fields to have this test Threshold testing is important to monitor changes in chronic conditions Especially glaucoma where you have may have slight threshold depression Going forward not necessary absolute So the the threshold test maps out the decibel level In a in a glaucoma test of the central 30 degrees that are important in glaucoma So in addition to the grayscale of the results, there are plots of total deviation pattern deviation You know and other statistics that Which help to eliminate the overall depression from such things as cataracts? And then the statistical analysis which some of the most helpful things there the the we see on a regular basis are The GHT which is a glaucoma hemifield test to see if there's a superior and inferior difference whether that's Within normal limits or borderline or outside normal limits and then an interesting a Statistic called the VFI or the visual field index, which gives you a percentage of visual field So I don't know if you can read that that the normal field To your right Which is in fact the right eye is 99% whereas the left eye on your left in the on the screen is I Can hardly read that myself 81% Is 61, okay. Yeah that that sounds better So outside of the eye doctor's office visual field testing is not quite as sophisticated But done properly it can determine whether an individual has a severe problem. So even a vision screening tester that flashes lights nasally and temporally Like the titmus tester you see there I can detect a significant visual loss like a hemianopsia Screening can be improved with an arc perimeter if you can find one That can measure the horizontal meridian And which is the primary one tested for occupations to the closest one degree just with a wand That's actually set up. It looks like it's set up and that shot for a 90 degree there But if you put it horizontal you come in with a with a wand and the individual can tell you where Where they can first see it Similar results can be obtained with this Relatively new inexpensive Hand-disc perimeter that's sold by Brunel, you know not pushing it, but it's available out there. It's in the bottom, right? That might be useful. I think those things are only about $50 The future of visual field testing may be the head-mounted field devices that have recently been released by a number of manufacturers and it's looking as though they compare very favorably to the Humphreys ice testing because they have sophisticated algorithms that Much like the 30-2 test that we use for for glaucoma or the 24-2 if we're using that one and But that's just a you know head-mounted system, which is a much less expensive than Humphreys ice with apparently Similar and perhaps in the future even better results. So that's what I see Happening in the future. I made a bold statement on a zoom meeting last night that that will be Standard of care within five years. I got some looks that was that was pretty bold, but it looks Looks like it may go that way All right, so thank you for your attention I hope you guys again as I said I hope you got at least one or two clinical pearls out of this and I think we have some time for questions We have some on coming in on line there that I did not address along the way And it looks like some of these we lost sound Utility is there one for let me take one from the audience first. Hey, good morning Could you go could you please go back to your last slide the one with the tip miss on it? Sure So I wanted to just ask your opinion regarding the ability for the tip miss to pick up Lateral field visions because I know you know, it's got the blights. It's got the blinking lights there And I think a lot of people myself included have relied on the the measurements from that machine I think you know just like 50 75 whatever In terms of the ability for that machine to measure or detect peripheral vision What are your thoughts? Well, I mean, it's not ideal but remember we're having to Make the best of what we have in You know occupational health clinic settings sometimes That one has even come up In even development of standards is a problem I'll get to that in a minute. It's really administration of the test. I think it's reasonably valid If the person is situated in the instrument properly And if it's administered properly The improper way of do things I think can probably be best visualized by going to any DMV The way that I've been tested there has been ridiculous visual acuity, can you see the fz bd4 line? Yes, I can oh then you pass and on that one do you see the little light flashing to the right yes, I Mean who's gonna if whoever wants to pass if you get administered, you know that in those Ridiculous ways is going to answer. No so if you do Try to administer them properly. There's going to be a light flash To one side of one of your eyes, you know, tell me what where you see it Then it's then it's reasonably valid for for what we We do now again. This is only you're only testing one point. So is that point only? You know a couple of points there temporarily are those the only points where there's actually visual field and there's katomas throughout you don't know that So It's it is not the best. I think the the other Perimeters or at least test along that meridian and see if you have any other skit omas along the way But are you going to go to a more sophisticated threshold? Visual field test on everybody. I just don't think it's possible. Oh So what I was mentioning on this so on this particular test, you know based on the numbers you get A hundred and fifteen degrees is one of the year your visual field measurements Well on most law enforcement's the the standards out there if you look at the literature They're showing that it should be a hundred and twenty degrees Well, I've drafted some standards and put in a hundred twenty degrees were our test. What do we do if it's 115? it's like well, you know based on the In just the Unique spots of this that you're only looking at specific spots I would say a 115 should be considered a pass when we set the standard at 120 and Let's say we can't have the standard and the test be different. You need to set the standard at 115. It's like well, that's That's not what the literature supports. So, you know, you have some of this these issues Do you are you do you want to write your standards to what the testing equipment available is or do you want them to redesign? The equipment perhaps move the thing five degrees so that we can test to the test of the science Anyone else in the room? Otherwise, I'll see what we have. Oh, yes Can you compare the computerized color visiting testing like Ravencone contrast and Wagoner's to the plates and does that help with some Eliminating like the timing errors and lighting errors that we see with using the plates Okay, so actually the Ravencone contrast and Wagoner's are good examples of ones that are are good because those aren't ones that you're just Going out onto a website and getting so those are those are computer-based color vision tests but they are ones that are that are very well controlled and Invalidated and you'll see agencies FAA even accepts Some of those the ones you want to be Careful of are I think there's something called coal blind or dot-com and they'll have they'll have things you can go out there and do the test and unfortunately practitioners if you're sending individuals out to to have additional color vision testing if they if they fail your plates and they again aren't really You know engaged in this enough to know why this is important they'll just find one online and send in the results so If you're on that end of it be very careful as to What you are saying? Okay, this is what they did here was valid. Just be skeptical unless you see that it's one of the the ones that's you know the traditional ones in-house or Some of the validated ones like the Ravencone contrast or the Wagner are two great examples of ones that are good Yes, oh So if there are no effective ways to correct color deficiency What kind of restrictions you recommend for people who work in the hospital? Particularly people who administer medications such as nurses and doctors. Oh Okay, there were the question towards me. So they were basically color vision requirements for nurses doctors there have been some proposals in the literature that Yes, I mean physicians based on how Diagnoses are sometimes made on color change need to be color vision normal And some have proposed before entrance into medical school You have to pass color test and it's like and it has never gone anywhere I mean even in optometrists, I Don't think there's been a study done really the optometrist is a color vision, but there has been some on binocularity because Interestingly enough, you know in a binocular indirect ophthalmoscope where we look at very subtle elevations in the retina looking for you know, whether something is Just a Maybe even a flat retinal hole that's not very likely to attach or something. That is that does have some Elevation underneath if it is likely to attach in the future With that. Well, one of the instructors at an optometry school is like a 40 diopter trope So, I don't know how he perceives what's going on in a binocular indirect ophthalmoscope, but do you need binocularity? and There there is if you want to go on You know PubMed and look at some of those, you know color vision and physicians There have been some proposals that it's needed now I think what hopefully has happened is those individuals that have gone through the curriculum in in whatever profession and have found that they've Had some struggles will go into the space specialty where it is less needed. So Haven't thought out which ones would be but you can think of those yourselves or certain specialties that would be Able to function better with color deficiencies and other ones where it's color normal color vision is going to be critical. Yes, sir Thank you for your overview. It's very good. I actually review a lot of physical examinations from a wide variety of Occupational medicine clinics throughout the United States and it seems like death perception stereopsis is the weakest Screening test that I see because they'll fail the individual because it's Death perceptions required as a central functions of the job. I Asked them to see an optometrist. They Go and nine times out of ten they pass Sometimes the optometrist will actually say yes better than 40 arc seconds so and then sometimes they'll just Pass them without actually giving a specific degree of death perception and maybe they just have marginal or Or minimal death perception. So it's kind of confusing to me as to do I pass them? I usually will pass them if the Optometrist will say yes, they have death perception and do you have a Standard where you would say well below 40 arc seconds. They don't have adequate death perceptions by OSHA standards or whatever. Okay. Well it that a lot of things in that so the Let me start with this just to give you an idea overall if an individual has bifovial fixation so They are not they don't not have any strabismus 98% of those individuals with bifovial fixation will have 80 seconds of stereopsis or better or should have should have the capability of doing that Why they may not get that in your testing situation could be because you are you testing in an instrument like a tele binocular? No, I don't know what these Occupational medicine clinics are using. Yeah, but they just sort of say they fail They're you know, they don't have any death perception. And so to give a break to these Applicants I'll say look why don't you validate that by going to an optometrist and my question is is should occupational medicine clinics have two different types of Stereopsis tests and if it's such a subjective Test or you know, well, I wouldn't necessarily say it's subjective But you know if you if you look in a tele binoculars a lot of things going on there one there For one, I mean the the test distance is what about a foot maybe in reality But it the optics within the tele binocular instrument whether it's truly a tele binocular or similar Is trying to trick you into saying, you know, that's really distance So, can you really be tricked I can but I can be tricked so I if we switch from distance to near on that my I adjust but some people have Other things going on with their system could proximal accommodation or proximal convergence most important with stereopsis in that It's like okay. This is supposed to be a distance, but I know it's near so I'm really Overconverging because I think it's a 12 inches even though the optics are trying to get me to optical infinity And if that's the case, then they're not going to perform as well on that particular test of stereopsis So that's why sometimes they will go to a you know, the the handheld type Stereopsis test and perform better in the optometrist or ophthalmologist office as well as Oftentimes and it should be the case before they're tested for that in in the office. They're given their best correction And the best correction for that distance So when they're looking through the tele binocular if they're a bifocal wearer Are they looking through the distance or not and things are a little bit blurry or the bottom it should be ideal Correction for the test distance of the stereopsis test, but for those practitioners who are saying pass and aren't giving you You know arc seconds number I Wouldn't accept that. I want I want a number because particularly the standards are different They can be 70 seconds. They can be a hundred of different occupations have different standards there. Thank you Yes, sir. Thank you Yes, ma'am Thank you so much, it's a beautiful presentation, thank you for me so far Vision testing is a challenge That's why I'm here So I have a question are you aware of any recent study about evaluation of vision tests after correction of Epiretinal membrane because I have seen that diagnosis Is frequent Many many providers or physicians too. They don't they are they don't know what is that? Okay, so you're seeing a lot of epiretinal membranes is what I'm getting so you are you dealing mostly with older population than I hope I'm sorry Are you dealing mostly with older populations because I agree that that is a fairly frequent finding but typically only in Older populations I would say over 60 for the most part you can find less than 60 year Okay So what an epiretinal membrane? Will do for those of you are unaware with that epiretinal membrane used to be called Cellophane maculopathy because when you're looking at the retina what it looks like is you've taken a piece of saran wrap Crunched it up and then laid it on the retina because it has a really wrinkly appearance to it So that will give you typically if it's in the macula reduced visual acuity and Sometimes kind of a metamorphopsia because you've got a you don't have a flat surface For imaging there, so things look a little irregular If it's not on the macula It may not affect very much a lot of times it seems like I see a lot of these between the disc and the macula And a person doesn't know they have any issues, and I just kind of tell them it's there We need to watch it going forward or even do an OCT to image it to make sure it's not changing but no specific tests for somebody with that other than very closely monitor their visual acuity and Have somebody that's looking at the retina closely monitor it that way there is a procedure for that where Vitro retinal surgeon will go in and actually do the membrane peel and just kind of peel it off and that typically will improve visual acuity however, just due to the risks of a vitro retinal procedure like that for other You know things like retinal detachment occurring. They're typically not going to go in there and do that Probably unless the acuity is reduced to 2040 or worse in most cases I think My question was a little bit different. Okay, so my question is is if you are aware of any Recent research study Knowing a new test for measurement For measurement new new test after correction a new research a new research test or project or That that is mostly for people post Surgical or post correction No, because well if I understand what you are asking then I would say that we want our individuals in any occupations to you know still Live up to the same standards as anybody who's not had surgical procedures. So I Would not say there's any Any anything beyond that that we would do post operatively It would still be the same Standards for a particular occupation. Okay. Thank you. We'll talk afterwards if that didn't answer you sufficiently anybody else in the room and I Oh Okay. Yeah for those online. It looks like we're out of time. They may have even cut us off, but If anybody wants my email If you're still on there by any chance Oh says live stream offline, so they're not gonna get it so my email address the best one to get me at probably is J L Weaver OD At gmail.com JL Weaver OD at gmail.com And thank you for coming appreciate your attention great questions, thank you

Jeff Weaver

vision issues

occupational testing

Gregory Good

visual acuity

refractive error

color vision

depth perception

visual field

Snellen charts

log-mar charts

driver's licensure

occupational safety