 Good morning. I'm grateful that we can have this grand round presented by the patient support program. I'm also grateful that today we can consider the research aspects of vision rehabilitation. Under the direction of Dr. Olson and Dr. Ord, an excellent patient support program has been developed to provide assistance for patients in need when the outstanding clinical team has already provided the diagnosis and treatments which they can. Of course, this recognizes the excellent and advanced care provided here at the Moran by optometrists, ophthalmologists, specialist ophthalmologists, and subspecialists. My gratitude to all of you who care for those, give the care which is given, and I'm grateful for the privilege of working with you. Today we are privileged to have Dr. Donald C. Fletcher with us. I am confident knowing Don that he would prefer this introduction to be, hi everybody, this is Don. But I do feel that a more formal introduction is necessary. Don is originally from Edmonton, Alberta, Canada. He has done more than anyone else I know in regards to the clinical research regarding vision rehabilitation. Don received his bachelor's degree at the University of Alberta with first standing honors. Dean's Honor Roll, he also received his Doctor of Medicine at the University of Alberta. His ophthalmology residency was at the University Hospital in Saskatoon, Saskatchewan. A retinal vitreous fellowship was completed with Dr. William E. Jackson at the Presbyterian Medical Center in Denver, and a low vision rehabilitation fellowship was completed with Dr. August Colon Brander at Pacific Medical Center in San Francisco with additional training with Dr. Eleanor Fay at the Lighthouse in New York. Dr. Colon Brander and Dr. Fay are world recognized as being pioneers in vision rehabilitation and joins them in being recognized as a true pioneer in the field. Don has received the Distinguished Alumni Award from the University of Alberta, the Secretariat Award, and the Senior Achievement Award from the Academy. He's a clinical associate professor at the University of Kansas, and an adjunct associate clinical scientist at the Skeppens Eye Research Institute. He is a reviewer for ophthalmology, for archives, and the BJO. He has completed 17 international volunteer missions, has trained 25 U.S. and international fellows, has brought four vision rehab products to market, has three current NIH grants, 19 completed supported projects, 79 publications, and over 200 presentations. I am personally grateful that Don has been an associate instructor in my class at the Academy for many years. While in San Francisco, Don became very concerned about addiction recovery and is embarked on an additional career in addiction recovery medicine. Don has completed an addiction medicine fellowship in 2018 and 2019, and now he has a VAX waiver for 100 addiction treatment patients. I always enjoy listening to Don speak and appreciate his exceptional understanding of the subject he will be discussing today, retinal adjustments in the presence of foveal scotomas. Good morning. Hi everybody. Here's Don. We will be monitoring the chat. If you have any questions, please send them in if you're on Zoom and we'll bring them up in the course of the conversation. Great. I have lots of material that I can talk about with you today, but I'm anxious to interact and have any questions that are brought up, discussed as they come up, because we don't have to cover everything that I've got on today. Thanks Bob very much. Bob's a long-term friend and it's always fun to be here and use. I've got two kids live in Draper actually, and so that always draws me close here, and I work in an addiction medicine clinic in Murray a few days every month. I did that fellowship, so that's my new hobby, is addiction medicine and treating opioid addiction. But I have spent 35 years doing low vision rehabilitation and I counted up somewhere between 30 to 35,000 patients I've seen now as low vision patients. After the retina fellowship, it became the whole focus of my career. I didn't do retinal surgery after the first year of finishing my fellowship, because I fell in love with vision rehabilitation and my whole research and most of what I've done has been looking at retinal pathology and correlating function with pathology. So I've done a lot of research with scanning laser thomascope and hope I can share some interesting little tidbits as we go along here. So that advance is good. I wish I had more financial disclosures, but I do have two little tests that I came up with, California Center of Vision Field Test and Smith-Kettable Reading Test, which I'll be talking about today, which I do get a commission from, so I better note that, although I don't have bricks and bricks of gold from that by any means. Okay, I'm going to tell you my take home messages now and I'll tell you the end again, and this is hopefully some important things that we're going to cover today. The visual system has some remarkable mechanisms for adaptation to disease and damage. Rehabilitation can assist the visual system and the human being to adapt. There's more division than visual acuity. I just hate it when presentations say the vision was 20 whatever. No, that is the acuity and there's a lot more division than just acuity. So that's why my little hobby courses that I get on. Ophthalmology does not stop at the level of the retina. Each eyeball belongs to a person. Don't forget to refer for low vision rehabilitation in your clinical practice. Okay, my first day of ophthalmology residency was probably like many of yours. The chief resident took me on to tour me on the facilities and the last stop on the tour was the low vision clinic. He said this is misnamed. It should be the slow vision. He said this is the most boring, awful, cruel and unusual punishment given to residents have to spend time in the low vision clinic. He really thought it was awful. So that was his image of it. He suggested that a reclining chair as noted there should be used for the ophthalmologist because it's so boring that you're liable to fall off a three-legged stool kind of thing and hurt yourself if you don't have a reclining chair. So the patients and the doctors all sleep during it. Well, that was my introduction and I do not think that's the nature of low vision rehab. I would actually propose that it's an exciting word and challenging, stimulating, wonderful, absolutely fantastic area of ophthalmology. So it is certainly one that is still very young and developing. I work for the Helen Keller Foundation and I have great respect for that wonderful woman and she said, one of the things, life is either a daring adventure or nothing and that goes for all of us, including the visually impaired and blind. So again, low vision rehabilitation is more than magnification and that's the way often we're introduced to it and that slow vision clinic at the University of Saskatchewan in Saskatoon Canada was pretty boring because all they had was magnifiers and it was pretty slow. When I was doing my retinal fellowship, I can very distinctly remember the great emphasis that was placed on finding all the holes. There's no sense doing a sclerobuckle and only getting six out of the seven holes. You're not going to have a very good success rate if you do that. So you want to support and buckle all the holes, address them all. With low vision rehab, there's holes in people's lives, skitomas in their vision, and if you don't address all of them, you're not going to have the biggest success. At Moorfields, great high center in London, Humphrey and Thompson did a study several years ago at their low vision clinic and found that after one year prescribing of their magnifier, 77% were not being used at all. They were in the drawer gathering dust and that's a rather discouraging statistic if you're just looking at magnification. But if you have a traditional kind of low vision clinic where you measure acuity, calculate the resolution deficit, show the person a few magnifiers, sell them a magnifier and never see them again, to me it's not surprising that 77% of them are not going to be used because with retinal pathology, with macular skitomas, even using a magnifier takes a tremendous amount of practice and there's a lot more to life than just using a magnifier too. So my approach would be to approach low vision rehabilitation the same way we do in orthopedics or neurology, where you have a team approach and the patient is part of that team. So in low vision rehabilitation, you need to develop an understanding in the patient of their residual visual capacity and then help them develop compensatory skills, drill for skill kind of mentality. And that's what happens in other areas of medicine. Why not in vision rehabilitation? So look story here anecdotally of Larry here who lives in Lawrence, Kansas. He was a KU fan and he was a bowler and had macular generation and had around 2200 acuity, something like that. So you'll see in his hand there a little magnifier and his little bowling jersey kind of thing. He's at the scoring machine. He was really excited to get that magnifier because it enabled him to push the buttons and this was for automated bowling alleys and so he was the scorekeeper. He'd put in the numbers and pins and so on like that and he was delighted that his magnifier allowed him to do that. His occupational therapist said, well, aren't you bowling? He says, no, I can't bowl. I'm legally blind. I'm 2200 acuity. No, you can bowl and she had to go to the bowling alley with him and bowl a few times to prove to him. But to make a long story short, yes, keeping score was great but he actually got quite good at bowling. He was quite a funny guy and he wanted to get a white cane from our orientation mobility specialist and we said, well, you don't have a lot of mobility problems, you know, why do you want a white cane? He says, just for the psychological advantage you'll have over my opponents when I'm bowling is if I tap my way in with a white cane and then put it down and throw a strike, it's just going to demoralize them, you know, they won't have a chance. So he won the league that first year actually. He really is a good bowler. So again, there's more to vision rehabilitation than just a little magnifier that he had in his hands. So it's a team approach and these are just some of the team members that I've worked with doing some of the various things that I think are important to comprehensive low vision rehabilitation. So a little study that we did, this was actually one of the University of Missouri Kansas City. I'm at KU, another crosstown rival. But we looked at about 220 patients and their goal accomplishment. And remember in the Humphrey and Thompson study, I said that 77% of magnifiers weren't used. Well, when we went a year back, a year later after discharge of our patients, 75% were actively using their magnifier daily kind of thing. And only three had given up and said it was unsuccessful. But 20% were using it, you know, intermittently spot reading, perhaps. But that's the exact, you know, flip side of what the more fields I experienced was. And this is giving patients an average of about five hours of training. So, you know, in your low vision technique where you just sell the magnifier and send them on their way, they're not getting that experience with how to maneuver around their central scatomas and so on. Other goals, meal preparation, self care, handwriting, shopping, so on and so on. Overall about 80% accomplishment of the goals that the people set. So I think that's pretty significant. And making a real world change in the lives of these people. So that was kind of macro level. Let's go down to micro level now. What happens when the phobia doesn't work? You know, it's interesting that I went through medical school, ophthalmology residency, and a retinal fellowship. And nobody ever mentioned or thought about that I ever hear any concern about what happens when, you know, you get a macular scar that encompasses the phobia. What does the I do? I don't remember any dialogue at any point ever about that. And that is really important. If you don't have a functioning phobia, how do you function? You know, your textbooks will often have a little black hole floating around in the middle of the picture. Nobody will describe that that just does not happen. The world does not look like that to the patients. Our eyes are very good, our brains are very good at perceptual completion. So this is this triangle, you remember, where the inside becomes the outside. And you have real difficulty making a perceptual completion of that because it doesn't make sense when one side's the inside one side's the outside. But what are the amazing things with this little optical illusion? I've put little gaps in there, and you don't have any problem completing the edges of the triangle across those gaps, because you're able to draw in the missing pieces. And thus, people with macular scatomas are able to do that too. And they fill in the missing pieces with what they think should be there. So patients don't see their field defects. Remember, the brain is all the same, not just the eyeball. Okay, this is an optical illusion that I really quite like. I want you to really stare with as much concentration as you can at the lacrosse, okay? On this picture, there are only 12 pink dots, and one dot in sequence goes out. But if you stare at that X, that cross in the middle, you'll see green suddenly appearing. The missing dot becomes green. And if you hold your eye real steady, the pink totally disappears. And you've got only a green dot going around in a circle. So that's a visual perception as in a way you can fool it. The after image opposite of pink is green. And if you don't move your eye, you do have extinction of phenomena. So one of the adaptations to this to see what's really there is to keep your eye moving. When you don't move, you don't see accurately. When you don't move your eye with a macular scatoma, you don't see accurately either. And the main function that I have to do as a vision rehabilitation professional is teach people how to move their eyes. Because that scatoma becomes negligible when you are, you know, constantly moving it around your brain does a completion of the overall picture. To accomplish that visual system use uses something called a preferred retinal locus. Plural would be loci, preferred retinal loci. So in an eye with a central scatoma effecting all of the fovea, the development of one or more eccentric PRLs or preferred retinal loci naturally and reliably occurs. Just by a quick show, I've had how many of you are familiar with the term PRL, preferred retinal locus? It's not one that we talk about a lot. It's really important. You know, when you lose the fovea, where is the center of the person's visual space? It's at the PRL and they will develop an oculocentric reference point. An up, down, right and left is not based on the fovea. So when you have them look at an Amzler grid, they do not ever look at the Amzler grid with the dead fovea and stick it in the middle of the Amzler grid. They use the PRL, the preferred retinal locus. So if you're trying to interpret an Amzler grid, you know, you can't assume that the fovea is aiming at the center of the Amzler grid. It's not. And the visual system's ability to fill in Amzler grids is remarkable. So Amzler grid, in my mind, isn't worth papers printed on. But anyway, that's just my little aside on that. So this is an example of a PRL. You've got a macular scar right in the center. And let's say the PRL, in this case, is anatomically inferior to that macular scar. The person would rotate their eye down, which then pushes that PRL up into alignment with the tree if they're trying to see the tree. That's actually the least common way that it goes. The most common is actually up. So the most common spot for PRL when you have a relatively round macular scar is up. Most people move their scatoma up. It's of best functional significance that way, because we don't do that much up there, but we do lots down here. You walk down here, use your hands down here, you read down here. So there's a strong drive to push the scatoma up instead of down. No, that example it was. But that's actually the opposite of what is the most common scenario. About 40% of people put the PRL anatomically superior and about 10% put it anatomically inferior, and then the rest is split between right and left. So about 25, right, 25 left, 40 superior and 10 inferior. And there's a lot of different factors that go into that. What's binocular correspondence, and what's the least amount of linear distance between the fovea, the dead fovea, and PRL. So if you have an oblong one where you have a lot more of the scatoma anatomically superior, then you might put it inferior. Is it obvious enough that the examiner will see the person? It has to be almost 15 degrees of eccentricity before the examiner will notice it. I'm good, so I can do it at maybe eight, nine degrees, but not with less than five degrees. You really can't appreciate it. So the patient comes in and they're looking at my forehead. They've got a fairly big eccentric viewing angle. If they're looking at your forehead, they've probably got a 15-degree eccentricity. In monkeys that have their foveas, that wasn't her. Okay, question is how long does it take to develop a PRL? I think one of the best studies was in ablating monkey foveas, and it took a matter of weeks to really develop a good PRL. When I watch a fairly rapid onset of an exuded maculopy that makes fovea function lose, it's just weeks. You'll do this not months, but weeks. You'll develop a pretty good stable PRL, so it doesn't take long. It's rudimentary, quick, and then it stabilizes and becomes more functionally effective in a matter of weeks. Is there another question here yet? There's a similar kind of mechanism. Sorry, the question is, is this analogous to anomalous retinal correspondence? Yeah. The brain has the ability to put attention on different areas. There's a number of stridobismic and different situations that can give you something similar. In ROP with drag disks and so on, you may have the fovea there, but you'll have an angle cap or whatever because of the physical of it, but there's a lot of situations where you can develop anomalous correspondence. It happens in a lot of macular scars where they're uneven size. It's amazing how the visual system can kind of calibrate so that you don't see double. I've had out of that 35,000 patients I've seen that are low vision, probably 70% of them don't have a functioning fovea, and I've only had maybe six or seven cases of diplopia where people have PRLs that don't match up with each other. The visual system does a pretty good job of working along LAD and making your retinal areas coincide. An anomalous retinal correspondence would be similar. There's a follow up question. Do people develop a PRL in unilateral vision loss? Yes, if they, wait a second. The better eye, yes, the lesser eye not necessarily. If you have a big macular scar in one eye and a functioning fovea in the other eye, you probably won't develop a very good PRL in the lesser eye with the big scatoma, but when you do an SLO study and you put up a stimulus, you'll see a pattern of where they go to look at it. Even though it may not be a very stable one, there'll be some rudimentary evidence that there is the start of a PRL at a given eccentric angle, but it won't be very good if the better eye has a functioning fovea. I'm going to come to that in a few slides. Scanning the azarothalamoscope, where you do visual field tests on the retina instead of in a perimeter bowl or whatever. So this guy has an anatomically superior PRL, and he's looking at your forehead, and that's, you know, about 15 degrees of eccentricity. And you can see he's looking at the photographer's forehead. This is a scanning laserethalamoscope. They were invented at Scape and Syros Institute in Boston probably early 80s, 1980s. And what it simply does is gives you an image of the retina and lets you project stimuli onto it, and you can have the person responding in real time to what's happening on the retina. The California Center of Visual Field Test is my cheap way of doing a visual field test with a laser pointer, and that's where I get the commission. And so on everybody, if I have an SLO available, I use the SLO. If I don't, I do the CCVFT with the laser pointer test. But here's an SLO image, the person with a macular scar, and we've asked them to look at the cross, and the fovea is somewhere within that macular scar. And this person is using anatomically temporal retina, and they're moving that scatoma to the right, so it's a right eccentric viewing position, and that is the adaptation for the development of the PRL is move the eye right. The downside of that is, of course, the next word is, and when you're trying to read, it's always in that blind spot, so it's a real pain to have a right-sided scatomas. Now, here's the perimeter that we did, green dots are seen, red dots are not seen. So you can see that macular scar is pretty dead. It doesn't appreciate any very, very bright lights, you know, it's very dense scatoma. Now, interestingly, here's the fellow eye, and this one has a superior EVP, very eccentric viewing position, anatomically superior PRL. And this person actually did experience diplopia, one of those seven or eight people that experienced diplopia, because they were both about equal quality PRLs, and they weren't going in the same direction, and he had diplopia. There's the perimeter on his eye. Okay, so training with respect to those PRLs, the PRLs naturally and reliably occur, but the skill in using them is acquired. Patients are not aware often of the relationship of their PRLs to the macular scars and the scatomas, so they'll naturally develop an ability to use the PRL to look at whatever they want to look at your face, you know, navigating around the room, using a magnifier and reading. They'll pretty, on their own, naturally get good at aligning the PRL with the object of regard, but they'll be totally oblivious to where the scatomas are around them. And when we train them to become more effective readers, we're really looking at increasing their awareness of where the scatomas are, so they can make compensatory eye movements, and deliberate scanning strategy, and also hand-eye coordination, because that all gets messed up when you move your eye, like, to the right or up, your pen doesn't go down where your PRS point, and it tends to go down where your old fovea is pointing. I'll show you some examples of that. So this is a study that I did with Ron Schuchard, one of my major collaborators, looking at the error rate when reading pre- and post-training. And so pre-training with the best magnifiers for the person's problem, people were making about one error every 25 words, and post-training it was one error every 89 words. That's quite significant. That amount of accuracy is a big improvement. Now, here's an interesting case, when I was talking about hand-eye coordination, that will be an example of this. The PRL in this individual is also in temporal retina. It takes a right eccentric viewing position, a movement of the eye to the right, to align up the PRL with the object of regard. So if you're looking at your release, they'd actually be looking over here, and you'd think, is this person not, you know, looking at me? Why are they trying to avoid my gaze? So right eye movement. Now, the occupational therapist asked this person, just as a training exercise, to find all the letters of the alphabet, and use the red felt pen to cross out the letters. Just look for the A and the B and the C and everything. And you'll notice, is this working? All right. They missed the A and knocked out the next letter. They made a mistake to the right. The C, a little bit off-center. The D, yeah, D was again over to the right. E was to the right. F, they were way off to the right. And so on. Why are they making mistakes to the right? Because that's where the phobia is pointing. And there's a well-established neuromuscular memory of your little rectus muscles, aim the eye over here, and that's where your hand goes, you know? So the hand-eye coordination has to be rewritten. And this is part of the training. And it's the software. It can be written. There's nothing hardwired there. But it's a really common mistake. So here's another example. The PRL on this individual is nasal to a scar. And this requires a left eccentric viewing position to get the PRL in alignment with the object of regard. Which one? This one? Yeah, I find it very interesting that the PRL has sort of nestled itself inside of that. Yeah. There's probably, this most doesn't work here, does it? Oh, there it does. Okay, I got it working. Okay, so if the phobia is, you know, two and a half disc diameters over, the phobia should be around here. And this is definitely dense scatoma here. But this is relative scatoma here. So the PRL was kind of in relative scatoma. The highest resolution, the smallest linear distance between the phobia and a functioning area is right here. So that's probably why they chose the PRL there. It's never good to sandwich the PRL between, you know, the scar and the disc. But generally the first driving factor to PRL location is where's the highest resolution. And then they go into other concerns. If it's round, then they go up. But if it's oblong like this, then they'll go to where the highest resolution is. And so I'm assuming the highest resolution, you know, was in this area here. But that put this bulk of the scatoma to the left-hand side. And there definitely was some eccentricity because it's always here. The PRL, you know, was at least five degrees off center. Okay, few bad. So in this exercise, the occupational therapist wanted the person to find all these words, head, boy, girl, clock, hat in book and so on. Take the red felt pen and draw a circle around H-E-A-D. If you look, there's a consistent pattern of overshooting to the left. So the F gets included with head for head. And it's girl includes the K on that left-hand side. So they're always going over there to the left and making an offshoot where the phobia is pointing. Now here's an interesting one. We do a lot of line tracing with this hand-eye coordination stuff. So the person is supposed to trace the triangles. And the top image is the person's first attempt at doing it, no training. This is the person with that left-extend interviewing position. So if you look at them starting on this corner here, they put the pen down here where the phobia is pointing over there to the left, and then went around and did their little drawing. Pretty consistently, a lot of overshoots to the left. After two weeks of practice, we give them homework and have them take it home. Look at right on. No improvement in acuity. That's just a neuromuscular, you know, anti-coordination skill that can be improved. And that has a lot of benefits for real world activities. Handwriting being one of them. So here's real world. There's the check pre and the check post. Now we also gave them the felt tip pen, which is a little bit bolder stroke and some bold lines, you know, checks and so on, which make it easier also. But that checks quite readable and they're staying on the line. And they were not staying on the line, you know, before they had that training. That's functionally significant. Okay. Lessons from the scanning laser ophthalmoscope, as I alluded to earlier, don't trust the amethyl grid. When I've had an absolute grid projected onto my optic nerve, I didn't see anything missing. All the lines were there and I had to have the picture taken and geez, that was on my optic nerve. My brain's very capable of guessing where those lines are going and filling in across it. And with Ron Schuchard, we found that if the scatoma is less than five degrees in diameter, the amethyl grid doesn't pick up 80% of them. So anything less than five degrees, the amethyl grid is useless, basically. If it's big, that's fine. But you're not going to know where the phobia is, where the PRL is from an amethyl grid either. And amethyl grid is used because it makes retina doctors feel good about being able to do something with their patients when they can't do anything else. I really find that an annoying test. Okay, so here's a scanning laser ophthalmoscope study. Sorry, question yet. Does the AMSR have any utility? Very little, in my opinion. And we put far too much confidence in it. The metamorphopsies that people experience, looking at door jams or curtain edges or something like that, I think are every good was good, probably better than the AMSR grid. If you have a sudden exudation and a change in the scatoma pattern, then you'll pick it up on the AMSR. But if it's small and subtle, it won't be appreciated. It has to be something pretty major in my experience for the AMSR to pick it up. The key is doing it monocularly, because when you're doing something binocularly, you're not going to pick up on a change in one eye. So do one eye, do the other eye, look at a door jam or look at the AMSR, whatever. That's fine to do it. Make sure you haven't done it monocularly though. Not just looking at it binocularly. And I think the door jam or the lines on the curtains back there or whatever are as good as the AMSR grid. But just have them do it monocularly. If you have the AMSR stuck on a magnet refrigerator, I guess that's not a bad idea. So think of it every time they go to the refrigerator to get their goodies. They can look at the AMSR and that's maybe not a bad idea. But it's, we have far too much confidence in it. Okay, we have a Scandinavian thermoscope image here of a person. The PRL is noted there in the center. That's the fixation point at the fovea. And they have a DS, dense scatoma, pretty much surrounding fixation. So a ring scatoma. And in patients that come to a low vision clinic, somewhere between 16 to 20% have this pattern of macular generation patients coming for vision rehab. Depends how big the central island is. So in this patient, they have a pretty big central island. That's probably, you know, three degrees across. So they can, they can deal with a fair amount of magnification. I've got an image here of words on a ring scatoma. And that'll give you some appreciation of how big a magnified word is. So let me bring that up. Okay. So I did a study in 1997 looking at 1300 eyes doing macular primary studies on them. And 16% of that study had ring scatomas. So the kind of, you know, configuration you can see down there at the bottom where the island is quite small and a massive big scar. This person may have, you know, 2040 acuity. And I've had many patients come in saying, you know, Dr. X or Y told me that I can drive because I have 2040 acuity and that I shouldn't have any problems because I have good acuity. And they can't do squat because that is such a small island that they've got the 2040 acuity. A single letter acuity does not translate to function in real world activities. There's a heck of a lot of things that are impossible to do with, you know, a one degree island. No, they've been shown to not help. York Prisms, most of the studies, most of the research that has been done in York Prisms have shown them to be of no particular value. So most of us in the research community are really down on York Prisms. There's still clinicians that use them, but the data doesn't look good for York Prisms. More sensitive than the Amster. No, no, face completion is pretty good too. You can have big chunks of the face missing and you can guess what's there. So looking at faces isn't particularly good either. Anything with a long straight edge on it, picture on the wall or the doorframe or whatever are, are, are, you know, pretty good. I don't know it well, but I think it would potentially have some value. I don't, I'm not really, really haven't used it, but I've heard about that and it, it, it may have some better value than, than an answer would. Yeah. That's a good point. I'll have to investigate that further. Yeah. Great. Good questions. Thank you. So this is my California central visual field test with a little tiny island in a big ring scatoma. So this, I flashed a little laser pointer onto a piece of paper and I, I like to binoculate because the SLO is, is a monocular test. So I do this one binocularly and I just have the patient tap the table when they can see my little light come on, on that piece of paper. And I can find most of the ring scatomas that way and some of them are very, very large. So this person had a, you know, a big scatoma because each of those rings is five degrees. So that's, that's a, the outer ring there is 15 degrees. So this person had like a 20 degree diameter scatoma with a one degree island in the center of it. And that corresponds to that eye back there. Okay. Now, here's an eight M unit size letter projected onto the retina. So if you have a ring scatoma like that and you magnify newsprint eight times, you're going to get two letters in there. So not very many. So when a ring scatoma, you have to be careful when you magnify more than the real estate available in the central area. But what happens if you do magnify that much is the person develops a secondary PRL is eccentric to the scar. And basically with ring scatomas, I find you give them just a little bit of magnification so it can still fit in that island if it's big enough. And if it isn't big enough, then you go to something like a video magnifier, CCTV, and you start dealing with 20 times magnification. And when you make it 20 times magnification, they don't have any choice but to have to go to an eccentric PRL. And they get pretty good at doing that. And that eccentric PRL has the advantage of being able to go horizontally back and forth. If it's a superior one, for example, and you don't run into the scatoma. So with ring scatomas, you start with low magnification and lots and lots of light, lots of light. So it will expand that central island. If that doesn't work, then you go to high levels of magnification and then try to develop a secondary eccentric PRL. I certainly understand what a ring scatoma is, but sometimes when I'm talking to a patient about a situation like this, I'll say it's like having a donut, holding a donut in front of the vision. You can only see through the hole and the rest of it is blocked. Absolutely. Or having a lifesaver stuck to your glasses. So wherever you look at lifesavers surrounding your central spot, because out here is fine. That's what the laser pointer, I like to demonstrate to the patients where they could actually take a whole laser pointer and, geez, look at that. It disappears in their kind of thing. So I can't remember when I put the study in here. If I come to it later. These scatomas, central scatomas, even when they're binocular, about 55% of people are totally oblivious to them. About 45% of people will say, things disappear occasionally. They'll have some awareness of it. And only about 1% of people will actually be able to see them. And it's only momentarily, fleetingly, when they first look up the ceiling in the morning, they'll sometimes see the scatoma on the ceiling. But as soon as they start moving, perceptual completion takes over and they don't see them any longer. But they will be aware. I had one lady give me this great story about, I'm aware there's a little blind spot in my eye because a cockroach came out from underneath the refrigerator the other day. And I was trying to step on it. And that darn cockroach ran right into my scatoma. She called it blind spot. And then around the other side, I could start trying to step on it again. But I thought it was really cute that she had an appreciation of her central scatoma because the cockroach hid in it. So here's a Scandinavian thermoscope study. And if you look here, this green area is the central island. There's a large area of ring scatoma around it. And then it's green out here again. So it's a ring scatoma. Here is a reading speed versus size plot. This is really large print. This is smaller. So this is about newsprint. And this is eight times bigger than newsprint. When you look at reading speed versus text size, this is in low vision path mnemonic of a ring scatoma. You don't need an SLO when people demonstrate this. This big text here, eight images in size, does not fit in there. It's like that word wonderful. Trying to read wonderful here is going to be really slow if you have only one or two letters at a time. So when you plot that out, these big sizes don't fit in central island here very well. So they're slower. So when you have a reading speed versus size slow, fast, and slow again, that's a ring scatoma. So just doing this reading speed, the MN reader, the SK read that I do, will tell you that. So a reading test is really good for kind of elucidating what type of scatoma pattern they have. So this is what the MN read is. MN stands for Minnesota. University of Minnesota is where this was developed. Gordon Legg, colleague of mine, came up with this really wonderful, wonderful test. And I'm amazed that in retina practice, we don't use this test more because you learn so much more about the architecture of the macula than you do from single letter acuity, which is only looking at a little tiny spot where you can read one letter at a time. When you look at the pattern that people have when they're reading and the speed that they can read at, you learn a lot about the macula in a really world activity, reading. So one of the soapboxes I get on and preach all the time. If we're doing research into macular function with whatever drug, whatever laser treatment we're advocating, have them do something besides just single letter acuity. And your endpoint for success or failure with treatment X or Y should be something more practical like a reading test other than just single letter acuity. You can tell I have some excitement about that. Okay. If we look back at the MN read here, this block of text right here, they were not able to finish playing the game before dinner, is projected onto the macula here. It's upside down and backwards, but that's print that's five times bigger than newsprint. So that'll give you what might fit into those little central islands. With that central line we were talking about before, you wouldn't want anything more than five and probably four M would be the most you could do maybe even three M three times magnification. So M units compared to newsprint. So five M is five times bigger than newsprint newsprint is one M. I can't believe that after all these centuries, we still use yogurt notation. The other was a print in Vienna, gazillion years ago, and the yogurt numbers come from his print box. They're not arithmetic. A J2 is not twice as big as a J1 kind of thing. So it's a stupid nomenclature that we still hang on to with a lot of our reading cards, yogurt units. M units are far, far better. So M units also subtend one M, subtends five minutes of arc at one meter. So you can, a 6-6 is the European way of expressing cuties, six meters and a six M unit letter. But anyway, in reading, this is where that M and read test comes in so handy because I look for the last print size that they can read rapidly because there always is a slowdown at a certain point on here. And that's my starting point for magnification. So if, for example, here, the last block that could read rapidly was they were not able to finish playing the game for dinner, and they started slowing down below that. The last one they could read rapidly is my starting point for magnification. So if they're critical print size, the last good reading was 5M, then I give them a 5X magnifier as a starting point. That's just an easy way to figure out where you, you can use Keston-Bombs formula and on your OCAPs you're going to have questions about Keston-Bombs formula, which is dumb. It doesn't really work that well. Just using a reading test like that is a far more sensitive way of doing it. This is a test called the SK Read Test. Sorry, I'm going to break my, patting my back. This is a really good idea that I came up with from the MN Read. So if you look at the MN Read here, this is the 4M block right here. My father asked me to help the two men carry the box inside. I noticed very frequently people with left-sided skatomas, a PRL, which put the skatoma to the left of fixation, would mistake that block of text and read to me. My father asked me to help the women carry the box inside. I noticed time and again, the T would be dropped when there was left-sided skatoma. Then, hey, why don't I do that on purpose? Because often people won't verbalize the mistakes on the MN Read. You'll see them slowing down and they'll look at it, they'll scan back and forth until they get it right. Something makes sense. So I developed an MN Read Test with just jumbled letters and words where it's easy to make a mistake where your letters are easy to drop and you still have something that makes sense. You don't have any context to go on. Okay, a little bit of time left. So here's some text from my SK Read Test. It has the same size of print as the MN Read. But here's a person with a left-sided skatoma and the typical kind of patterns they make. They thought box was ox and there's no sentence to make them correct it. Two men becoming women still flowed and made sense. But here, there's nothing that makes you want to correct it. So you just go ahead and read the mistakes and don't know if you've done anything wrong. After reading that first line, they started on grow and omitted the letter B on that left-hand side. And then they thought harm was farmed. They substituted an F for an H there. Those are all going to tip you off that the main problem here seems to be on the left-hand side. So when you're looking at the training with occupational therapists, you're going to be doing the SLO is great. My CCVFT is great. But this is a really good, good way of looking at the functionally significance of a test. Right-sided skatoma here. Saved became save. Raises became raise. Mad space T became mad. H was dropped on the right-hand side. So again, you can see the pattern there. This person was making mistakes to the right. And sure enough, the SLO showed they did have a right side of the mistake. So we compared the MN read and the SK read on a hundredth consecutive patients. And on the SK read, this block of patients had a thousand errors. And on the MN read, they had 175. So you have 10 times as many errors, which gives you a much better handle on a pattern that you want to see evolving on where the errors are going to be. So the MN read is really good for predicting magnification level. And the SK read is really good for looking at patterns of errors. So anybody that does low vision, I strongly advocate you get an MN read and SK read. It's great to have an SLO if you've got $15,000. That's wonderful. If you don't get these two tests and you can get a lot of really practical information for a couple hundred bucks. So this is the poor man's SLO. And actually, this is nice, mainly for academic interest, looking at, you know, macular patterns of adaptation. But this is real world. This is reading. That's what our major goal is for people that have low vision. Okay. Again, I alluded to this earlier. Using the CCVFT, the laser pointer test, 80% of my patients in a low vision clinic demonstrated binocular scatoma. So that's a lot of people that are having to dodge scatomas in a low vision clinic. And 66% had a binocular dense scatoma. And only 56% had, sorry, 56% had a totally or oblivious to the fact they had a scatoma. Sometimes there was the largest 30 degree diameter scatoma. I mean, I think these words are a blind spot. I don't know about any blind spots. It's amazing how good the visual system is at adapting. But it's important that the patient know about it because they're going to have functional implications of that. Their reading is going to be really difficult if they don't know how to move that scatoma out of the way. If we look at the people that were aware versus those that were unaware, the people in my initial study that were aware of it had a much higher reading rate than those that were not aware of their scatomas before any rehabilitation foreign treatment. One last visual field test that I think is kind of fun. It's a dynamic visual field test. This is an idea that Ron Schuchert and I came up with that I think has a lot of, again, functional significance for living with scatomas. In this test, fixation is discouraged. Move your eyes around wherever you want. There's no central fixation point you got to stay steady on. Move. We want you to move. Any central stimulus on the test is just for reference, not for fixation. And when we put a stimulus up, we take away the central fixation point. The stimulus patient stays up until the patient identifies it. And your outcome measure is the reaction time, not whether or not they saw it because you leave it up until they see it. So here, for example, there's a central fixation point and then we present land wall C and we wait until they say, right. So they allow them with the time run and we look at how long it takes to define it and respond to it. Next stimulus, we got to wait until they see it and they say up. Next one, they say down and you go all around the visual field doing that. So you have a plot like that and then you can put on a grayscale. So on the SLO, I know that this person has a field defect to the right of fixation, a right extended viewing position. And it's interesting that's where the reaction time for the slowest. So the stimulus will sit in that scatoma and the patient doesn't see it. And then they think, hmm, it's been a while. I've heard the beep. Maybe I should look for it and then they look for it so that latency is what you're looking at here. And this really improves with training. So this is kind of an endpoint where our therapists are doing a good job and the patient is getting an appreciation. Yeah. Absolutely. Totally accurate. That's what they say. I have a focusing problem. I'm not, I can't focus my eye right. And it's aiming their eye, not focusing it. You just have to aim their eye and position it more accurately onto the PRL instead of some other area that's not as good. Yeah. So how do you handle that question in a clinical situation? That's a big part of education in your initial visit is showing them where the scatomas are. So when they indicate that, I said, yes, we'll come back to that. We'll come back to focusing later and we'll look at spectacles later. Right now I want to start out with looking at your visual field here because this is usually the cause of what you're describing, the problem you're describing is some blind spots in your central field as opposed to a focusing problem. So many of my patients complain about not being able to recognize faces. Do you have an easy answer for them? That's the first symptom of macular degeneration. I think that before anybody has any reading difficulty, they have difficulty recognizing faces. That's more a contrast issue. So as you lose contrast sensitivity, facial features become blurred. So you can tell there's people there, but you can't tell there's Thomas Dick over there waving at me kind of thing. So a really common problem, it's tied in with all aspects of vision loss, decreased resolution, scatomas. Main thing I think is contrast sensitivity, but that's a hard one to improve too. I tell them, you got to put your pride in your back pocket and tell all your friends you got a vision problem because other ways to think you're snobby. They didn't smile at me today when you walk by Don. How come? What's the matter? You got your nose in the air and sorry, I didn't see you because very subtle little clues like a brow ink. When you see somebody, you know, they raise your eyebrows and when your low vision, you don't see that little raising of your eyebrows and if you look at somebody and raise your eyebrows like that and they don't do it back to you, that's cold, it's icy. So it's very socially significant face recognition and so it's really important that low vision patients, I have more picture. All right, I have to go up here, screen one out, that they know that other people should know about their vision problem and say, hey, hey Bob, it's Don, you know, when you walk up to them because face recognition is almost universally a problem with everybody that comes to our clinic, right? Yeah. Okay, so there's the dynamic visual field test. Here's my central tangent visual field test and this one was quite similar. Okay, so awareness of central field disruption facilitates more deliberate scanning strategies, they navigate and compensate for visual field problems. Again, I want us, you can tell I'm excited about this passion. Acuity doesn't tell the whole story. So in any kind of research you're doing, use more than just acuity. My take home messages, the visual system has some remarkable mechanisms for adaptation to disease and damage. Rehabilitation can assist the visual system and the human being to adapt. There's more division than visual acuity. Ophthalmology doesn't stop to level the retina. Each eyeball belongs to a person. Don't forget to refer to low vision rehabilitation. So thanks for your attention and I got a little bit of time for questions if anybody's got any here. What would you say for the comprehensive ophthalmologist watching today on Zoom as the take home message for them as they see somebody with cancer? I think one of the things that all ophthalmologists should do and it doesn't take a lot of time while you're doing your history, ask a few functional questions because the people with ring scatomas are going to have good acuity and they're going to have a lot of functional problems. So I mean something as simple as do you have difficulty reading? A screening question is a great starting point through a low vision rehab because you can make assumptions and begin to really trouble assuming on the base of acuity that people do or don't have problems. So just ask, do you have trouble reading? With your glasses on, do you have trouble reading? And if they do then you need to think, well maybe with some pathology here that I'm not recognizing maybe a low vision referral is appropriate. General ophthalmologists I think are very fine to remember that ads don't stop at three. It's okay sometimes to give a four or five ad to some people. That's all right. What else would you say? You answer the question. What else would you say to general ophthalmologists? I think the point about a plus four and a plus five in an ad is correct. So the question from Dr. Kurt Kopp is, are there commercially available training programs to help patients use their PRL? Yes, there are some, they're available through the American Occupational Therapy Association and my OTs are the ones that developed it. There's a really good one actually that I think probably precision vision carries. So you can get it through precision vision which sells our ADTRS charts and that too. Learning to use your vision for reading. Lover, L-U-V-R, learn to use your vision for reading. And that's a really good training book for a teaching person to read. Mary Warren's got a few other ones that are sold through the American Occupational Therapy Association but Gail Watson did the Lover book and that's a really good one. L-U-V-R, learn to use your vision for reading and I believe that precision vision sells that. Good question. Yes, that was the last one. Learning to use vision for reading. Yeah. Sorry. Yeah, question. Well, the first key was getting reimbursement for it. So I'll repeat the question. How could we expand this and get more comprehensive programs doing more than just dispensing magnifiers? That's certainly something that Bob and I have been advocating and talking about for a long time. We both worked with the revision rehabilitation committee of the American Academy of Ophthalmology. So at the academy we have publications and we have courses and we try to do that to try to increase awareness. But the real key I think to it was getting Medicare reimbursement for occupational therapy, for example, to do the training for these patients. I'll break my arm patting my backing. Through the American Academy of Ophthalmology we did a lot of work on the Lover's rehab committee to get that coverage through and there's no reason to not do it now because you can make money doing it and there's occupational therapists that are trained in this. There's two postgraduate programs that give vision rehabilitation training, one in Philadelphia and one in Birmingham, Alabama and their first class and you get therapists that are coming out that are well trained. So I would say it's really appropriate for any retinal practice to adding an optometrist, heaven forbid, an optometrist, one of our rival professionals there and some occupational therapists to low vision service. That would because that's where the bulk of the patients are. They're going to be going through retinal offices and so that's a model that I've used. I'm a retinal trained doctor so it was easy for me to preach that but I've had a number of, I've introduced a number of low vision practices into retinal practice. So the model that I would see as being really effective is for retinal doctors to become more involved in it and employ an optometrist and some occupational therapist. You could get a lot of good with that. If you got more money than you know what to do with then do a clinic like I've got in Wichita. We've got I think 7,000 square feet in our low vision clinic that's five-story building and it's the Taj Mahal of low vision clinics. We have a lot of money and that's why I'm in Wichita. So the answer to that question is also a new one starting in the clinic. Casey has also used ESP reading and he's the occupational therapist that goes to someone home after they've had a vision rehabilitation here. Dr. Olson in the chat says, Don, fascinating and important lecture. Many thanks for taking us through a too often neglected area in our field. Teresa Long, what should we tell our patients in preparation to help them get the most out of their low vision? I often ask them to think about the tasks they have the most difficulty with and or the tasks that are important to them but they are not unable to do anything else. That's a really good question. I hope your voice came across on that. What should people tell their patients as they go to low vision clinic? I notice a huge difference in the mindset of people that get a positive note from positive message from their doctor. If you tell the person that they're legally blind and that there's nothing else I can do but you might as well see the low vision clinic guy, that's a real negative referral and they're not going to have very high expectations. If on the other hand you say, Hey, we've got this great occupational therapist in our clinic here and a good low vision program and they'll be able to do a lot of good and I think you've got really good potential to be able to use your vision better with some of the training and devices we've got. So I'd really like you to go and see this because this is the best thing I think we can do for you right now. We can't do any more injections or treatments or lasers or whatever. And so setting the stage for success is great. And telling somebody they're legally blind, that's like telling somebody that's in the hospital that they're legally dead. You're not blind. I hate that term with the passion. Talk about a negative label. So you find, Oh, you're legally blind, but go see the low vision clinic. I'm blind. Why should I should bother going? So setting the stage with a positive message of encouragement and hope is the most important thing the referring doctor can do. I am H.O. Don, thank you so much. It's been wonderful having you here. Thank you so much.