Advanced OCT Imaging Prevents Blindness

[00:00:00]Your eyes reveal what you cannot see.

[00:00:02]Hidden inside them are clues [music] to diabetes, high blood pressure, heart disease. Detected before you [music] have any symptoms. Onethird of diabetics discover their condition through an eye exam. Today, meet the [music] expert who's using advanced technology to see what's invisible to the naked eye.

[00:00:19]Technology that's saving vision, saving lives. Stay until [music] the end.

[00:00:27]>> Welcome to Open Your Eyes with Dr. Carrie G, the podcast where we cut through the noise and give you real actionable insights to protect your vision and your health. Think about most medical tests, blood drawers with needles, contrast die injections, biopsies that require cutting tissue, or imaging that exposes patients to radiation or uncomfortable procedures.

[00:00:52]These tests give us critical information, but they do come with a cost, a risk, and some invasiveness.

[00:00:59]Now, imagine this. Getting microscopic layer by layer detail of living human tissue. What many call an optical biopsy using nothing more than a gentle beam of light. No needles, no injections, no radiation, no pain, just a quick, comfortable scan that takes seconds.

[00:01:19]That's the power of OCT or optical coherence tomography. One of the most advanced diagnostic tools in all of medicine, yet completely non-invasive and patientfriendly.

[00:01:32]But here's where it gets even more powerful. The same technology is allowing us to detect and monitor sightthreatening and even life-threatening conditions earlier than ever before. From diabetic retinopathy to age related macular degeneration to retinovascular changes, they may signal increased risk of stroke. The eye is no longer just about vision. It's a window into systemic disease. And the question is, are we just imaging the eye or we beginning to predict the future of patients health? Today we're we are diving into this revolutionary technology with one of the leading educators in retina, Dr. Caroline Major.

[00:02:17]Dr. Major is a prominent optometric physician and educator recognized as an expert in vitro retinal disease and retinal imaging. She is an associate professor and director of residency programs at Northeastern University State University Oklahoma College of Optometry. Dr. the major. Thank you so much for joining me today on the Open Your Eyes podcast with Dr. Carrie Gelp.

[00:02:42]>> Oh, it's my absolute pleasure, Carrie.

[00:02:44]Thank you for having me.

[00:02:46]>> Caroline, I I really appreciate you coming in and you're well known in the industry as a great teacher. I know you have uh some websites and Instagram.

[00:02:56]What's the name of your in Instagram and and uh your website uh Facebooks that if people want to look at and learn more about OCT, what what are they called?

[00:03:06]Uh yeah, so my Instagram is retina queen. Um and I do have a website where I have most of my lecture hands out posted which is octangio.org.

[00:03:16]So I like to always start off with a story. So tell us about a story where a patient that you've had where you've done an OCT or an OCT angography that either saved their vision or even saved their life.

[00:03:31]Yeah, I think OCT angography allows you to detect the earliest treatable proliferative diabetic retinopathy. So in cases of diabetic retinopathy, you can get these new blood vessels that grow up outside of the retina and we call that proliferation. And when that happens, it puts a patient at risk of tractional effects. So that may be a lot of hemorrhaging like a vitrius hemorrhage in the eye. That could be a retinal detachment potentially. So once we start to see these early neovascular vessels or proliferation, we want to do some sort of treatment right away. And as a primary eye care provider in optometry, it's important that we recognize the earliest proliferative diabetic retinopathy and make a prompt referral to retina for treatment. And so I can count at least like probably 10 to 20 patients where I would have missed the proliferative form of the disease had I not had OCT and especially OCT angography. Um but it's also helped me you know diagnose some subtle diseases that otherwise again I feel like I would have missed like really early macular tangictasia type two. There's these subtle tangentas in the deep capillary plexus on OCT and geography and making that diagnosis is you know so critical to have OCTA >> with more screen usage and indoor time.

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[00:05:14]>> Well, that's great. And we're going to talk a little bit more about that as we as we move along in the podcast. So, tell us the difference between OCT and OCTA. Let's start off with OCT. What is OC?

[00:05:26]>> Yeah. So, OCT, I like to explain it to patients and to students as like an ultrasound, but instead of using sound waves, we're using light waves. So it allows us to generate these really highresolution microscopic sort of detail of the retinal layers that otherwise we couldn't get in a non-invasive format which is amazing. And so OCT we're basically looking like they call the structure side of things. So what are the retinal layers? Um whereas when we look at OCT and geography, it truly is more of a functional test where we're looking at retinal blood flow and also coroidal blood flow in addition to the structure. So what I love about OCT and geography is it's not like either or.

[00:06:11]It's like OCT or OCTA. You with OCTA you get the structure but you also get the vascular information superimposed kind of on top of it which is really great.

[00:06:21]So it's like a plus plus. [laughter] Why is it so uh so special to be able to look into the eye and look at the blood vessels as opposed to what other doctors do? Uh is there any other doctors that could actually see blood vessels other than optometrists or opthalmologists?

[00:06:38]>> You hit on a point of why I love OCT and geography and retinal blood flow so much because as eye care providers, we're the only type of physicians that we can actually look inside the eye at the blood vessels out in the open. There's no skin covering them. So oftent times we're actually the first providers to diagnose some systemic or medical condition like hypertension potentially diabetes, anemia. There's so many, you know, systemic conditions that can affect the eyes and the blood vessels that we can visualize first.

[00:07:11]>> You know, when I started practicing optometry, we didn't have OCT. You know, the retinal images were very, you know, basic back at the in those times. And when I use an opthdoscope, if I saw a hemorrhage, mostly people knew that they were diabetic or they were diabetic. We weren't picking up diabetes before the people knew they were diabetic. So I was looking at the the blood vessels probably at about 150 microns at that time. Now with OCT, we could see the blood vessels at eight microns and there's technology that's going to be a we're going to be able to see at one micron. So talk about the importance of being able to see blood vessels so early where we could diagnose disease before the antartitis could see disease.

[00:07:56]>> Yeah. So if we pick up eye disease early, not only does that help us treat the eye component early on, which usually means a better visual prognosis, a better better vision outcome, but also we can then treat the medical side early on. So you know unfortunately there are patients with like type 2 diabetes who have little to no symptoms especially hypertension as well that is an asymptomatic disease in most patients right so if we're picking it up early on our eye examination making an appropriate referral to a primary care like uh internist for that diagnosis they can be treated early right whereas there are some patients with type 2 diabetes they'll have it for years and years and years with like blood glucose levels I've seen like five 600s you know causing a whole lot of damage not only to their eyes but to their kidneys, their, you know, blood vessels all throughout their body. And if we can pick that up early and treat it, that's going to ultimately save that patient from a lot of vascular damage throughout their entire body.

[00:08:56]>> And for the doctors, the the non-d doctors watching this, describe the image behind you.

[00:09:02]>> Oh, [laughter] OCT and geography, which yeah, is definitely one of the the loves of my passions of my career. So I don't have a good point. Yeah, this is actually like the optic nerve head right here. And then we can see all the blood vessels coming out of the optic nerve and basically supplying the the retina. This is a patient with diabetic retinopathy actually. So you can see there's some areas of like retinal non-perfusion and Irma as well. [laughter] >> I mean it's a great picture. You know OC ch OCT has changed a lot over the years.

[00:09:33]I mean we started with time domain OCT.

[00:09:36]talk about how we've gone how imaging has changed from 10 to 15 years ago to today.

[00:09:43]>> Oh gosh, in so many ways like just with the advent of OCT and then OC and geography came out gosh maybe 10 years ago now. Um, but as the speed like the acquisition speed of OCT keeps getting faster, it's going to allow us to get even higher resolution scans because the more scans we take and average together, we can get higher resolution because we can minimize like the noise and the speckle. So the faster the instrument can scan, the more scans we can take, the more averaging we can do and the higher resolution we can get. And it's also that speed that allows us to do OCT angography, which is why we didn't have it when OCT first came out. And so we're able to get not only faster scans, but wider field of view scans. And I think the future is really headed towards zoot and geography like wide field imaging out in the mid- periphery the periphery on like a single capture whereas now we have to do some like montage um kind of knitting the pictures together to get out into the arcades. And you know certainly as doctors we're learning a lot about patients medical uh conditions because in the old days where we just used to look at the center part of the retina now we could see all the way out to the edge where we'll see some peripheral hemorrhages and changes of the blood vessels and micro aneurysms and at that point we could refer to primary care primary care or internist for labs and a lot of times these people will be pre-diabetic or diabetic and we're picking up diab this much earlier.

[00:11:16]So if you could comment a little bit about the periphery.

[00:11:20]>> Oh yeah certainly. So the peripheral retina uh is very important to examine not only from like a blood vessel standpoint but from you a structural standpoint. You could have breaks in the retina. Um so if there's a full thickness defect in the retina that's going to allow fluid from the vitrius to get through that sort of hole or defect that potentially cause a retinal detachment. So viewing and imaging that peripheral retina is really important because if a patient has a high risk type of retinal break, we can do some laser around that break to prevent it from causing a retinal detachment in the future. But from a blood flow standpoint, there actually some diseases that uh sort of preferentially affect the peripheral retina like cickle cell retinopathy, you know. So it's very important that we have good imaging out there. You know, you can have tumors out in the periphery. So, if you're not looking out there, these things are going to be missed.

[00:12:13]>> You know, it's interesting. A buddy of mine, uh, probably 10, 15 years ago had a peripheral hemorrhage. And, you know, he was he's an optometrist. He was worried. He went to the opthalmologist.

[00:12:23]He said, "There's nothing to worry about. I'm very interested in functional medicine." I was saying, "Your insulin's probably high. You're probably pre-diabetic." He kept on his same eating schedule, didn't change his lifestyle, and he did become uh diabetic. So there are clues to systemic health as well which are very interesting whether you know microanorisms that we could see some of the earliest changes if you could just comment on that a little bit.

[00:12:49]>> Yeah absolutely. So I think not only retinal hemorrhaging micro aneurysms but even what we call cotton wool spots which is basically like uh an area where the blood flow has been oluded to the or blocked but to the very like uh anterior portion of the retina. You know all those things are saying that there's some sort of microvascular problem not only in the eyes but that's going on throughout the entire body whether it's you know diabetes whether it's anemia I mean sometimes severe bilateral or hemorrhaging in both eyes can cause like be caused by serious things like cancers like leukemia lymphas I mean so so many diseases >> yeah little microanules with cotton wool spots could be a sign of endothelial dysfunction >> which is the earliest sign of cardiovascular disease. And these are things that we could pick up by looking in the eye. And that's where things are going. We're going where we're going to be using the eye as a biioarker to help diagnose systemic disease, not only eye disease. Now, in the old days, we used to do a lot of florosine angography. You know there was a recent study done uh I think it was done in 2005 or 2006 that the amount of florosines done by retina specialists are down between 50 and 70% because of OCT angography. So if you could explain what florosine angography is the pros and the cons and OCT angography the pros and the cons verse florosine angography. Well, seed angography is an invasive test where we're actually doing a die injection into the venus system that then gets, you know, pumped to the heart and circulated into the eye. We use a special camera with optical filters that allow us to see and highlight that blood flow within the eye. It is a 2D sort of static image that we're taking as opposed to like a volutric cube of data that we get with OCT and geography. But the advantage I think of uh true florosing angography is that we can see where the dye is traveling over time. So when you get the injection done, they take like a series of pictures for a minute. They then wait a few minutes and take like a late phase photo. And so that allows us to pick up especially that late phase photo if there are any blood vessels that are damaged. And so that dye and fluid is leaking out of that blood vessel. It's like hyper permeable. we see these patterns of like leakage or staining or pulling in the late phases of true florosine angography that we can't capture with OCT angography because it's basically we're looking at the blood flow at that that time that the scan was taken.

[00:15:35]However, you know, with OCT angography, we said that's a non-invasive test.

[00:15:39]We're basically just taking OCT technology but doing that scan like four times in the same location. We're looking at the differences between those four scans and any differences is assumed to be due to the red blood cell flow. So the principle behind how we acquire OCT and geography images is what we call motion contrast because we're comparing those four scans and the difference is blood flow. Because of that we can combine it with OCT because it is OCT technology. So a huge advantage of OCT angography is we get the structure OCT and the angography like vascular data at the same time on top of each other which allows us to draw correlations between structural abnormalities like let's say there's a pigment epithelial detachment in a patient with macular degeneration and we want to know is there neovascularization under there is this patient neovascular exudative AMD we're able to then flip on the vascular information look at those patterns to see oh is it vast theorized is this a patient that maybe needs a referral to retina another huge advantage I think of OCT angography is that volutric cube of data that we can actually pull out individual layers of the retina something we can't do with florosine angography and we can also pull out abnormal blood vessels like that proliferation or neovascularization in uh diabetic retinopathy I was talking about earlier there's a segmentation analysis that allows us to look at just the abnormal blood vessels and it does that automatically for us so that it makes my job like so easy in terms of oh yes this patient is proliferative so my diagnosis is more efficient my diagnosis is more accurate >> is there any advantage to seeing the periphery with florosine angography that you see more peripheral further out on the retina than than OCT angography >> definitely I'm glad you brought that point I forgot to mention that in my answer there. So, florosine angography does allow us to do more wide field imaging and that is incredibly valuable because a lot of patients with microvascular disease such as diabetic retinopathy most of the non-perfusion is out beyond the arcades like in the mid-p periphery and the periphery and there were some research studies that suggested the degree of peripheral non-perfusion on florosine angography is a risk factor for progression of the retinopathy. So patients that have a lot of retinal non-prerofusion are at greater risk of becoming proliferative in the future and we can't see that far out with OCT and geography right now but in the future it's definitely coming down the line within the next few years I think >> now with with uh with florosine geography where we could see leakage with regular OCT can we point the OCT where we think the leakage is so we can see that there's edema so can Can we s can we use regular OCT instead or it's still not good enough compared to florosine angography?

[00:18:45]>> Um I think regular OCT you can get clues that maybe leakage is present. Um, for example, if you see like fluid pockets, intestinal fluid, subretinal fluid.

[00:18:56]However, you won't know for sure if that's coming from a neovascular complex or tangictas and like say MCtel type 2 unless you're doing some form of angography whether that's you know OCT angography or floroscene angography.

[00:19:12]Also, you know, I think an important thing that that most um like eye care providers can forget is that hemorrhage does not show up well on OCT. Like that is definitely a downside of OCT. Whereas just looking at the fundus in a patient say that has um age related macular degeneration is so critical cuz I've seen patients with hemorrhage on fundus exam that was pretty subtle and then on OC there's no fluid but then I do OCT angography and there's like a neovascular membrane right underneath where that hemorrhage was located. So I think it's so important to recognize that hemorrhage is better identified on clinical exam. Um, but only OCTA can we directly visualize the membrane itself, not just the secondary clues of it.

[00:19:57]>> Now, I'm making an an assumption here, but you you correct me. Uh, being at a university, I assume that there's probably you have a lot of different cameras, a lot of different brand cameras for looking at hemorrhages. Is there a certain camera that you favor to be able to pick up hemorrhages versus other cameras?

[00:20:16]>> I am incredibly spoiled at the university. I love working here. Yes.

[00:20:20]Um, we have the Zeiss ClariS which is widefield ultra wide field true color imaging. Um, I love it a lot. We can still magnify up and see things like on the optic nerve head and the macula even with just a single shot. Um, the single shot I think gives us about like uh 150 degrees give or take whereas if you do like a montage you can actually get out to like 200 degrees um in terms of the imaging. It's really nice. And with speaking of montage with OCT and geography, how far does that allow us to get out if we use a montage with OCT and geography?

[00:20:56]>> Yeah. So there is something on the the Zeiss Cirrus like angoplex is what I use. And so there's a 8 millimeter montage option. When you choose that, it automatically guides you through five 8 mm scans and then knits them together.

[00:21:12]And in the end, it will allow you to like retake any that it it wasn't able to combine or anything like that. When it knits those together, the combined image is 14 m by 14 mm. However, there is a single capture 12 mm option. Um, but the the montage gives you a little bit higher resolution. You get a little bit further out.

[00:21:34]>> And my understanding is that there are OCTs in Europe that actually go further out.

[00:21:39]I I'm not certain about that, but I would imagine so. I I think the the wider field of view is definitely coming in the US and like worldwide here in the near future because OCT keeps getting faster and faster and faster.

[00:21:52]>> So, let's look at some clinical applications. Now, some of this might be a little bit repetitive, but I think it's important that we make the distinction. So, let's talk about macular degeneration.

[00:22:03]uh uh compare the benefits of OCT angography versus florosine angography for macular degeneration for diagnosing uh neovascularization and because obviously we want to pick that up as soon as possible. Which way is better and where would florosine be better for macular degeneration?

[00:22:25]>> I think they both have a lot of value. I think where OCT angography shines is that because we can directly see the neovascular complexes before they leak with OCT and geography technology. It's the only thing that allows us to see what we call like a non-exudative coroidal neovascularization.

[00:22:46]So where we may have a neovascular net that hasn't yet started leaking out fluid. So there's no fluid pockets on OCT. There's no hemorrhage on clinical examination. There's no leakage on florosine angography. So we can't visualize it with florosine angography.

[00:23:02]We can only see it with OCT angography.

[00:23:06]And recognizing or or detecting those types of lesions, these non-exodative neovascular membranes is really important because it it's about a 15 times increased risk for a patient to become exudative and require anti-buff therapy if they have these occult non-exudative uh neovascular comp complexes. I think on the flip side is florosine angography allows us to truly visualize the activity of a neovascular membrane. So, is it leaking or is it not leaking? And so, it can sometimes detect membranes that may be missed on OC and geography if there's some sort of like artifact or media opacity or blood kind of covering. So, because OCT is using light waves, if there's some opacity on top of the nevascular complex like a hemorrhage, we can't get our light through it and so we can't see it.

[00:23:59]Whereas there are certain types of angography especially um like endocyining green where we can image deeper down into the coroid get past some of that pigment and better visualize these neovascular nets and know is it actively leaking or is it not and sometimes that helps guide whether a patient needs an antivf injection for macular degeneration or not. And for our non-d doctors watching this, we're worried about these neovascular membranes as doctors. Explain what that is and why it's so dangerous to the patient.

[00:24:31]>> Oh, and macular degeneration specifically.

[00:24:33]>> Macular degeneration. Yes.

[00:24:35]>> Yeah, certainly. So, you know, macular degeneration comes in different forms and kind of laymanly we say dry versus wet. And so, in the wet form of macular degeneration, uh what happens is you can develop these neovascular complexes. So new blood vessels growing uh underneath the retina and those new blood vessels are very problematic. Uh so because they're fragile, they're permeable, they can leak out fluid, they can leak out blood, they can cause a lot of scarring in the center part of the vision called the macula. And so it's this neovascular exudative AMD which is more the technical term for like wet AMD that causes about 80 90% of severe vision loss blindness from macular degeneration.

[00:25:22]>> Now were you were you trained were you working with the students and the retina specialists? At what point do they treat those hidden nets those hidden areas of these new blood vessels for the public the uh neovascular membranes? So, we see these hidden membranes, these occult membranes that are hidden. And what do we do about them? Do we they're not leaking? We know that that that like you said, there's a 15 times greater risk for them to bleed and they could be a become a problem, but are they are they early starting to treat them with with anti-ve treatment with laser if it's a part where they could use a laser or are they just following them? What what do we do?

[00:26:03]>> Yeah, that's a great question. But I think the practice patterns of retina specialists that I've encountered and asked to do vary. Um I would say there's some good research out there to suggest that they should not be treated with anti-vef until there are clear signs of activity which is like fluid on OCT or there's hemorrhage. However, if you're monitoring it with OCT angography, which is really the only way you can monitor it because that's the only way we can see it on OCT and angography. If the membrane is getting bigger, like every time you're so you should be doing it at least every 3 months, like imaging these membranes, if it's getting bigger over time, even if it's not leaking out fluid or it's doesn't have any hemorrhage, some retina specialists will treat that with antiv in that specific situation.

[00:26:47]But I'd say most retina specialists are waiting for the fluid, waiting for the blood. Uh because otherwise like what's your end point for treatment right that was a when I asked one retina specialist about the same question he was like well I don't know when to stop you know if I'm doing anti-vef therapy usually my clue that I've been successful in my treatment is a lack of fluid a decrease in edema on OCT and if there was no edema to begin with like how do I know what I'm doing is working and how do I know you know when my treatment is over or is it never over do we treat them every four months for life like I think there's still a lot of questions out there about these complexes, >> but the statistic you said about 15 times greater risk of it bleeding and going on to blindness or becoming wet. I mean, so you really have to balance those two and that's a I guess there's no clear answer. In New Jersey where I practice, it's the same thing. They're not treating them until there's a change or it's bleeding or or there's fluid.

[00:27:47]But, you know, sometimes the patient hasn't been examined in 10 years. So you you're getting them you're taking a picture as the bird is flying at one picture in time. So you know we don't know if it's been changing. Obviously there was a change or or wouldn't be there. But that's that's a very difficult question a very difficult quandry for us you know for the optometrist and the opthalmologist because obviously we don't want anyone to lose their vision. We don't want any be to become wet. So that's a very that's a those are very tough cases.

[00:28:16]>> You know I'd like to add on to that too.

[00:28:18]Um I want to make sure we've been clear in our definition of like non-exidative coronal vascularization. This is a patient who has never received prior anti-vegf therapy. Um and like you're saying we want to pick up the earliest conversion to exudation. So that is a patient that monitoring more frequently is absolutely critical. This isn't a patient where you're like oh I'm going to see you in a year. Like monitoring every three months is my protocol in a patient that has this non-exidative neovascularization where we're repeating the OCT. We're repeating the OCT angography. We're looking at the fundus to make sure there's not hemorrhage but also you know educating the patient to monitor their vision at home whether it's an amsler grid the nodal um vision for C home device I think is even better for detecting at home conversion to exudative AMD and a patient that has a membrane like that I think is a perfect candidate for that home monitoring system >> and I know is working on a home OCT you know >> it's FDA approved yeah >> you know So it it's a FDA approved now.

[00:29:19]And do you know how much it is for someone to get one of those home OCTs?

[00:29:24]>> I do not, but I don't think they purchase it. It's just sort of like an installation loan thing much like the um like perimery type of device that they have for metamorphsia monitoring. I think the homoct is more in the realm of retina specialists cuz they're trying to determine whether a patient needs an anti-ag injection with that homoct. It's not so much utilized to detect conversion to exudative AMD.

[00:29:50]>> And for those that don't know that are listening, what are what is antiaf that we're using to treat these lesions?

[00:29:58]>> Uh anti-vascular endothelial growth factor. So VEGF is a um substance that's being released from the retina or parts of the retina like the RP where there are areas of eskeeia basically. So there's not enough blood flow. It releases this VEF which you could think of it as like fertilizer almost. So it's this fertilizer that then allows new blood vessels to grow and proliferate within the retina. So it's like a compensatory mechanism. It's actually really cool when you think about it, right? Because the retina is saying, well, I'm not getting enough blood flow.

[00:30:36]Like how can I fix this? I can grow new blood vessels, right? But unfortunately, these new blood vessels are weak and fragile. They tend to easily break and bleed and cause scarring in the retina.

[00:30:48]>> So as we continue with clinical applications, we just went over macular degeneration. Let's talk about diabetic retinopathy and diabetic macular edema.

[00:30:58]The difference when we use OCT angography verse florosine angography.

[00:31:03]>> Sure. So OCT and angography is going to actually allow us to detect the earliest microvascular changes from diabetes inside the retina even before we can see it on clinical examination. Um but OCT is absolutely critical just structural OCT that is in looking for macular edema in patients with diabetic retinopathy and then classifying the location is it non-center involved is it center involved we know center involved diabetic macular edema is higher risk for vision loss and should most definitely be referred to a retina specialist for like consideration of of treatment >> and florosine used for uh diabetic. Oh, florosine angography. Very important.

[00:31:46]>> When would we use that for a diabetic?

[00:31:49]Florosine.

[00:31:51]>> You mean like as opposed to OCT angography >> or with or and like we're going to say we're not only going to use OCT angography in this patient, we're also going to use florosine. Where would that be more helpful? And we might have already covered this a little bit, but just to for completeness.

[00:32:06]>> Oh, sure. Certainly. Um so florosine angography because you get more wide field imaging it can sometimes be faster or more efficient in detecting peripheral neovascularization in patients with diabetic rhnopathy which most definitely does occur whereas OCT andography you can't like out there in terms of your field of view I think florosine angography also as well as OCTA can help you visualize areas of retinal non-perfusion or eskeeia where the retina is not getting enough blood flow and that um in a patient that's not yet proliferative is sort of predictive, right? We know that if you have these areas of poor blood flow in the retina, it's going to release more VF. And so that's a patient who's at risk of becoming proliferative in the near future. And I need to watch them more closely as a result.

[00:32:57]>> And we can see poor blood flow above your left shoulder. We see areas of capillary dropout and we see areas of the earliest signs of insulin resistance. We'll see we see some micro aneurysms those little dots above your above your left shoulder those little dots there and even areas of so which we'll we'll talk [clears throat] about later. So let's talk about again clinical applications. Tell us about vein occlusions uh or uvitis or tumors comparing florosine angography to OCT angography where where are they helpful for those?

[00:33:30]>> Yeah, retinal vein occlusion uh a huge utility of using um any form of angography and you know I think they're both very beneficial. So in retinal vein occlusions where a vein is blocked pretty much all the retina distal to that potentially has like leakage of fluid and edema or areas of retinal non-perfusion.

[00:33:53]And again using angography we can visualize this retinal non-perfusion that on clinical exam is almost like invisible. And because we can gauge like how much retinal non-perusion there is, we can then say is this eskeemic or a non-eskeemic vein occlusion and have the knowledge the predictive knowledge that eskeemic vein occlusions are likely to grow neovascularization.

[00:34:17]So if it's a branch retinal vein occlusion, it usually grows in the posterior segment like neo on the disc or elsewhere the retina. If it's a central retinal vein occlusion, usually neo in the anterior segment like on the iris and the angle potentially neovascular glaucoma etc. And both technologies I think do do a great job of showing you what's the degree of retinal non-perfusion although OCT angography can kind of highlight that in better detail than flores angography and also visualize that there's already posterior segment neo say from a branch retinal vein occlusion both technologies are able to pick that up I think very nicely and of equal uh efficacy where OCT angography shines in retinal vein occlusions are patients that have macular eskeeia Because OCT angography has higher microvascular resolution compared to florosin angography, we get these like exquisite details of the phobia vascular zone, the little capillaries that are around the phobia vascular zone. So we can actually measure quantitatively with some devices what's the size of the phobia vascular zone. Is it enlarged? Is there notching?

[00:35:25]Is an irregular shape that would be suggestive of macular eskeeia that we can't treat. So for example, if a patient has a retinal vein occlusion, they have concurrent macular edema and macular eskeeia, we know that treating with antiv, we're probably not going to have the best visual prognosis. Like we still should, but we're probably going to bottom out somewhere around 2060. You know, it's not going to be a recovery back to like 2020 vision because the macular eskeeia component we can't fix with antivf.

[00:35:57]And which one is better for monitoring uh uh anti-vegup treatment? Is it better OCT angography or florosine angography?

[00:36:06]>> I think when it comes to macular degeneration like florosine angography is superior because you can actually see the degree of like activity. Um OC angography we see some morphological changes in the membranes themselves.

[00:36:22]Like there's usually on a neovascular net some like little capillaries like lacy anastimos and capillaries on the margin sort of like leaves on the tree that you'll lose like pruning the tree or etc when you do anti-vef therapy and you can see this with OCT and geography.

[00:36:39]Um but that's not usually how we guide whether a patient needs antiv or not.

[00:36:43]The just the structural OCT is actually probably like the number one thing that's most important in guiding antiv therapy. Is there fluid or is there not?

[00:36:52]Is there thickening? Is that getting better? So just monitoring the response of the OCT retinal thickness and fluid is really critical in in antiv assessment.

[00:37:01]>> And the picture behind you, we see o OCT angography. How does it work? How does it make how do we get these kind of pictures?

[00:37:09]>> You know, so this is basically identical to regular OCT technology. However, we're taking like a macular cube four times in a row and we're comparing those four scans to each other and any differences between those scans is assumed to be due to the motion or flow of red blood cells within the vascule.

[00:37:31]Um, the reason you have to buy like an upgraded system to get angography on your OCT machine is because it has to be really fast in its scanning acquisition.

[00:37:42]Because imagine we're taking basically four scans in a row. We need to be able to do that like pretty quickly um to for efficiency purposes, but also you have to have some really souped up like motion tracking, right? So, if a patient's moving their eye around, even micro cicades will affect your angography cuz the the technology sees that as motion and it's like, oh, that's that's blood flow. And you'll get a really cruddy image if you don't have the motion tracking software engaged when you take the scan. And so these newer OCT models that have angography, all of them have some sort of like really great motion tracking software on them.

[00:38:20]>> So let's talk about different displays.

[00:38:22]Uh one of the favorites is on foss or face on top down view of the retina. Uh explain what that is and why is why is that one so good to use when we're using when the doctors are looking at it for diagnosing disease. Yeah, I think what's really challenging with OCT and OCT and geography is that we get a volutric 3D cube of data, but it's hard for us in like a fast clinical setting to sit there like scroll through the entire cube of data. So, a way that we can visualize a 3D cube in a 2D format is this infos generation of images. So an infos image refers to like a compression usually of several retinal layers down into a 2D plane and then turned like you said like top down sort of infos view.

[00:39:09]Um it's very popular with OCT and geography imaging but you can do it with structural OCT too if you just want to look at like the the stria of like an epireinal membrane or if you want to look at photo receptor loss and plaquinil toxicity. I mean there's actually a lot of great applications of just structural enfos but the angography on foss is the way that we primarily visualize OCT angography data and every device is a little bit different but there are often presets in the machine that'll be like superficial capillary plexus deep capillary plexus corocapillaris etc. You know I think what's interesting I remember when I was teaching uh the students would get confused about inner retina and outer retina. If you could explain inner retina outer retina and what diseases are we looking at in both.

[00:39:59]>> Oh certainly. Um so the inner portion of the retina is supplied by like the central retinal artery circulation. And so the infos images that would correspond to that would be like the superficial capillary plexus the deep capillary plexus. And that's where you want to be focusing your attention in say diabetic retinopathy, retinal vein occlusions cuz those primarily cause damage of the inner retina. whereas the outer retina we're referring to like the photo receptors RP um that's supplied by the choreocapillaris and so the diseases the primary one is is macular degeneration that could affect that but there are a lot of others like ocular hystopplasmosis myopia etc >> it's interesting how the retina has a dual circulation >> because it's so has such a high metabolic demand so part of the retina is is supplied by the coro capillaris, the other by central retinal artery coming off the optic nerve and then branching into all these different capillaries. So that makes that you know that shows how complex the retina really is.

[00:41:07]>> Definitely.

[00:41:08]>> So let's talk about some clinical stuff.

[00:41:11]If we're seeing uh we're looking at the eye inside the eye there's the vitrius.

[00:41:15]It's jelly in the eye that helps keep the eye solid. If we're looking in the eye and we're seeing blood in the vitrius and the person is diabetic, what are we thinking?

[00:41:24]>> Um, certainly. So, blood in the vitrius cavity in patients with diabetes is highly suggestive of like a vitrius hemorrhage and proliferative diabetic retinopathy. So you've grown these new blood vessels kind of on top of the retina that are attached to the vitrius and when the vitrius kind of tugs on it with maybe even just mechanically you know moving the patient's head or they secade when they're doing reading and the eye moves the vitrius tugs on those blood vessels causes a little rip in the vessel and it causes a lot of bleeding into the vitrius. Uh definitely a sign of proliferative diabetic retinopathy.

[00:41:58]And we're talking about scans before.

[00:42:00]The best scan for looking for that those dangerous new blood vessels for macular degeneration, the ORIX scan, the outer retinal corapillary scan. Can you talk a little bit about that scan and how it how it helps us?

[00:42:14]>> Certainly. Um the OCCC or the ORC outer retinal coro capillaris um is specific to the Zeiss Cirrus brand like of angoplex and you have to have like one of the newest upgrades to have that. I absolutely love that preset because it combines the photo receptors, the RP and down to the coro capillaris. So in a normal patient, all you visualize is like the coro capillaris sort of speckle on OCT angography. But if there's neo um or new blood vessels that are under the retina, under the RP in the koid, because we kind of encompass that whole space in that ORC scan, anywhere there's blood vessels, we're going to capture it on that scan. I mean it's it's it's a fabulous scan. It really helps us for diagnosing subretinal neovascular membranes. Oh yeah. To be able to see who's at risk for this massive bleeding or becoming a wet macular degeneration.

[00:43:10]And something also very interesting is the vascular information that's the red over the Bcan. If you could talk about that to tell us about the blood vessels and how that helps us.

[00:43:21]>> Yeah. So, a Bcan overlay refers to like our sort of regular cross-sectional structural OCT where we can see the individual retinal layers, but then an overlay, we overlay the vascular information like right on top of it. So usually in red, sometimes in green or different colors, you can overlay the blood flow information on top of the structural OCT scan. So again allows you to make like really important correlations between the structure and the vasculature to know is like a a peed potentially vascularized or often I'll use it say I have a patient with um like some degree of diabetic retinopathy on my structural OCT I can see there's a little like tuft of something hanging up in the prepapillary space on top of the optic nerve head and I want to know is that neovascularization of the disc or is this just a congenital like Bergmeisterers pill right If I do an angio scan on that and I scroll through my Bcan overlay, if it's perfused, it's going to show up as like red or pink and then I'll know is that neo the disc that's potentially a referral or is that just congenital gal tissue that I can, you know, ignore and kind of monitor and house >> and OCT and is really good for early detection of diabetic retinopathy, proliferative diabetic retinopathy. We mentioned MCTEL which we're going to talk about in a minute.

[00:44:41]uh let's talk about diabetic retinopathy clinical applications. So what are we looking for in a regular OCT and an OCT angography for diabetes and the earliest signs of insulin resistance such as micro aneurysms maybe Irma you behind you we could see some examples of that capillary dropout which is obviously would be later in the disease just talk a little bit about how we could use it for diabetics and help protect them and save their vision. Yeah. So I think I mentioned earlier like OCT and geography can detect the earliest changes in patients with diabetes and earliest vascular damage. Um I think OCT is critical for looking at macular edema and classifying macular edema but often on OCT you can see other things as well.

[00:45:30]So areas of retinal non-perfusion although you not you won't be able to directly visualize that with structural OCT you may have some atrophy or like thinning of the inner retinal layers due to past retinal eskeeia that occurred that then basically caused the inner retina to just like die off because it no longer had like blood flow. So some of those more subtle things you can actually visualize with OCT. We can also with OCT kind of gauge what is the prognosis of treatment of macular edema with anti-vef therapy based on how um like uniform or normal the retinal structure looks in the macula. So something called like drill like there could be disorganization of the inner retinal layers that then would be a poor prognosis with antiv therapy because you know sometimes patients have macular edema that's been there a long time it's going to cause some permanent damage and disruption of those retinal layers. Um I think OCT angography is critical for looking at macular eskeeia which commonly occurs in patients with diabetes. We can see really subtle features of non uh proliferative diabetic retinopathy like you point out before. So microanurisms, non-perfusion, areas of Irma, it really highlights Irma. Like you know the 421 rule, it was like the one they call prominent Irma, right? And if you look at the standard photograph of prominent Irma, it's really hard to see. Like Irma is really hard to see. Like one of the top questions I get from students is like I'll be like, "Oh, there's Irma." And they'll be like, "Where? Wait, can you point it out to me? I need to learn how to see it. OCT geography really highlights those sort of subtle vascular abnormalities for you so that you can accurately stage the disease. And then in proliferation, I mean OCography is paramount and I always do montage OCT angography in patients where clinically maybe I'm diagnosing them as severe non-prololiferative.

[00:47:29]But again, there's been like 10 or 20 patients where I thought it was severe non-prololiferative. Then I do montage OCT angography and it turns out they have like a small little area of neovascularization of the retina that I missed on my clinical examination. So I think OCT angography is so important in diagnosing early proliferative diabetic retinopathy that should be referred to retina. Absolutely.

[00:47:50]>> I know it's behind you on your left shoulder, but if you could point to the Irma.

[00:47:55]>> Yeah, you got it. Perfect. And you talk about how there's a a third of the patients without uh traditional diabetic retinopathy actually have abn abnormalities on OCT. If you could talk about that a little bit.

[00:48:10]>> Yeah, certainly. So there have been numerous research studies now that you know support this that OC tangography is the most sensitive test for detecting retinal vascular changes in patients with diabetes and in about onethird of patients with diabetes that don't yet have clinically evident retinopathy. We can see vascular changes on OCT angography and that's going to be a 3mm scan right in the center of the phobia where we get really high resolution detail of the phobia vascular zone may be enlarged in patients with uh early diabetes changes or there may be areas of non-perfusion some early micro aneurysms that we can't see on clinical exam.

[00:48:50]>> Now our classifications of diabetic retinopathy h hasn't kept up with our technology. So our technologies outpace classifications. Do you think the classifications that are going to be used to to grade patients are going to change soon?

[00:49:07]>> Yeah, definitely. And I think there's they're working on that actively right now. And I think it's going to include not only structural um sort of fundus findings, but also functional findings like ERG findings. [music] >> [music] >> With more screen usage and indoor time, myopia, also known as nearsightedness, is increasing and getting worse in children. Now certified eye doctors can prescribe my [music] site one day, the first and only FDA approved soft contact lens to slow myopia progression [music] in age appropriate children. Visit coopervision.com to find a Brilliant Futures certified eye doctor near