 I'm going to finish up about electro-retinograms today, excuse me, about 30 years ago they were done like I talked about the other day, but about 30 years ago is when they added the colored flashes that I told you not many labs use. Less than 20 years ago, a guy named Eric Sutter invented the multifocal electro-retinogram, which I consider the magic of visual electrophysiology. It's a really complicated program that in my computer is six million lines of code. And this program extracts from a single signal off the eye the electro-retinogram from less than each square millimeter of the retina. It's limited to the area you're stimulating. The common area stimulated is the same as a Humphrey 24-2. So approximately 35 plus degrees horizontal, approximately 30 to 35 degrees vertical. Most systems are similar to this. There's about six companies in the world that make multifocal systems now. Most of them are like this. A pattern is displayed and there's a chin rest such as this that sets the distance, the patient is away. Everybody uses the same stimulus pattern, which I'll demonstrate to you. If it runs. But Sutter alone, his company is what we use. Those of you that have seen me do multifocals, it's a little box smaller than a cigar box. And that one is a version of a miniature display. There's different systems. I have this system too, but it's not being used right now. It's in storage over on the second floor. The patient looks through that outer box. This has got an advanced thing programmed into it. And then there's a focus knob. In fact, on the left and right sides that has built into it plus or minus 10 diopters that the patient can focus for themselves. And then I have lenses to go up to 30 plus or minus 30 diopters for the individual patient. This is the pattern that everybody uses. This is off the video chip in my system. In my program that I use, which is set by the company, I use that the patient looks at this for 30 seconds at a time. And anytime at the end of a 30 seconds, they can take a break if they need to, if they need to move or talk or cough or sneeze or anything. I use the Burian Speculum contact lenses. You can see the patient's eye on my monitor like this. So you can coach the patient about maintaining fixation. I don't know why I have bird shot right there. But it's as good an example as any. The magic about the multifocal electro-retinogram is that you can map with an accuracy of each of these little hexagons. You get an electrical signal from each of these hexagon areas. This is the big blind spot or the blind spot. And it maps any areas of the retina that are deficient in function regardless of what the cause is. From as unusual as a one millimeter bleed in a patient, a pregnant woman with hypertension, to detached retinas, to mystery scatomas in the retina. Just some examples here. You can also get similar patterns for time, and that's what these are. Different disorders vary whether amplitude or time, implicit time, are delayed the most. That's interesting. Weird. How do I get rid of that? Is that F5? Or do I have to do it here on the screen? What made it happen? Weird. It gets Monday morning to the computer also. You guys will learn more about bird shot when you rotate through Vitaly and Shakora's clinics. The multifocal is really good to follow individuals such as with macular degeneration. It is not used to make the diagnosis. It's not necessary. And so except in studies, usually multifocal electro-retinograms aren't ordered. These are the electrical signals. Multifocal electro-retinograms from a person with macular degeneration. You can see that interpreting these is not rocket science. It swears Waldo. Do they look like these outer, which are normal? Or do they look smaller than they should be in the area that's affected? This is a color transformation, which is simply changing the B wave, quote unquote B wave amplitude of the multifocal electro-retinogram to a voltage in a color scale. Normals on the lower right. Really good use. And the most common use, at least here, for multifocal electro-retinograms is Plaquanil. Ten years ago I might not, might see a Plaquanil patient every couple of weeks. I see Plaquanil patients sometimes two or three a day. Not every day, but that's how common the use is for Plaquanil now. The great thing about the multifocals, it'll pick up abnormalities in the retinal physiology up to a year before a patient would notice, clinically notice the problem. Much, much, because visual fields depend on attention. And most, if you've surely learned by now, patients hate visual fields. I have had patients come to my door when they're going to do a full field electro-retinogram and see my Gonsfeld and freeze and say, oh no, I've had that. I don't have to have that. No, not again. Plaquanil produces and chloroquine produce the classic ring, scatoma, can vary a lot in its expression in the individual. This is a person with Plaquanil toxicity showing these islands of areas affected. Only one in, say, making this up, one in five of individuals Plaquanil toxicity showed the classic ring scatoma. Probably because you're getting them at different stages in the toxicity. Oh, I thought I had some better ones. Some do, though. I'm going to add to this. This is a seizure medication. You can also do ring analysis of the multifocal electro-retinograms where each of these traces, one, two, three, four, five, six, represents the average of each of these rings starting with one being in the middle. So normal is the dark one and then the red one is the patient. What's good about this, particularly for detecting toxicity with Plaquanil, is you might have one as normal and then two or three would be abnormal and then four, five, and six go back to normal again showing the ring effect. And sometimes you can see it in the traces and sometimes you can't. So I always look at these because sometimes this picks it up that it wasn't apparent to just visual observation of the traces. It'll pick up anything that's a visual field defect that originates in the retina regardless of the etiology involved. Here's the 32 of a patient. Here's their multifocals. Let me go back again. Here's the Humphrey on the patient. Here's their multifocals. This is the color transformation in the same patient. Normal's the lower right. You can map detachments, conspicuous upper right there, trauma, small detachments. What you got over there, Mao Leng? Go out for a minute. This is golf in Chinese. The guy here in Salt Lake City was hitting a bucket of balls and about 10 feet out in front of where he was, where he was hitting the balls was a little tiny concrete edge lip down at the ground. He hit a golf ball and it came back and hit him in the eye. There's his left blown pupil which stayed blown. He was a salesman so he got an artificial contact with an artificial pupil so he wouldn't look so weird. There's his Humphrey 32. These are his ERGs again back to the Humphrey. There's the ERGs and here's the color transformation. He was really lucky. He completely spared the fovea so he remained 20-20 in his vision. He just had this little field defect that went from about 3 to 5 degrees outside the fovea up towards 9 or 10 o'clock. That was his field. It's good for Azor. The particular person I'm going to show you was at the time he was 17 and it appeared a week or so after episode of Flu. Here's his visual field with his multifocal superimposed. We didn't get him until he was about a month out. He was from Northern Montana and he ended up here in about a month and at least since then, which was now about 4 or 5 years ago, he's never changed. He comes back once a year. It's completely static. Over here is the blind spot. So you have a really good patient like this. You get very good agreement between the fields and the multifocals. Small central scatomas. I'm just going to race through here, a detachment, small bleed during the episode of high blood pressure. I think it's, I can't even tell from here, I think it's up here. Does that look right? Let's see. There's the color transformation of it. Multiple central scatomas, detachment. Again, there's this, there's even a video of how to do these on web vision that's embedded in it as a link where the multifocal section starts.