Lecture: Topographic Widefield Analysis in Glaucoma

There is a growing clinical evidence that early glaucomatous damage involves the macula. The anatomical basis of this damage can be studied by measuring the local thickness of RNFL and GCL+ layer. Macular damage is typically arcuate in nature and often associated with local RNFL thinning in a narrow region of the disc, “the macular vulnerability zone”. According to Donald Hood PhD’s studies, most of the inferior region of the macula projects to the MVZ, which is located largely in the inferior quadrant of the disc, a region that is particularly susceptible to glaucomatous damage. We are going to explore and understand the relationship between anatomical and functional changes in glaucoma and the way the topographic approach with widefield OCT scans gives more insights about the pathology than the usual color-metric based diagnostic.

Lecturer: Dr. Jose Mendoza, Ophthalmologist, Lima, Peru


Dr. Jose Mendoza: So thank you for being here today. We’re gonna talk a little bit about topographic widefield analysis. And also about telehealth approach in glaucoma. So let’s start with the definition of glaucoma. Glaucoma in the 21st Century has the same definition that we have had in prior years. It’s a progressive optic neuropathy characterized by a specific pattern of anatomical and behavioral changes. So what we should be looking at is for evidence of arcuate-like defects. This is the RNFL distribution in the posterior pole. We already knew this for a long time. So the only type of defects that we should have been looking for in glaucoma are defects that affect this type of RNFL distribution. We have a particular zone that is very vulnerable to changes in the inferior quadrant of the disc and also in the superior quadrant. So these arcuate-like defects are what we are looking for on the superior part of the posterior pole or in the inferior part. There is no single exam to diagnose glaucoma. We need several studies. And that is time-consuming, and it’s also resource-consuming. So the clinical paradigm for diagnosis of glaucoma includes visual field testing and OCT scans of the optic disc. But this is facing three challenges. The macular region is affected early in the glaucomatous process, so this paradigm can miss or underestimate this damage. The use of typical visual field and OCT metrics underestimates the degree of agreement between structural and functional damage, and also, since the resolution of the OCTs has improved, and local glaucomatous damage can be visualized like never before, usually the clinicians don’t have time to look at the OCT scans, all of them, and we only see the reports. So we need to integrate all this information on a single report or so, to have… To avoid the misdiagnosis of glaucoma. So talking a little bit about the macula and the optic discs, there’s a study — this is taken from the study from Hood and Dr. de Moraes, in Columbia University. So the first picture shows the thickness map of a single healthy individual. This is a single eye. This is the cross sectional slice. This is the macula, the ganglion cell layer, for the RNFL, and the RNFL and disc. And this column is 128 control eyes. What this shows is that there is a pattern. That we have normal eyes. The pattern of the ganglion cell layer on the macula. The pattern of the RNFL thickness layer on the disc, and also on the macula, are the same on all the control eyes. So anything that will alter this pattern will be abnormal. That being said, there’s growing clinical evidence that early glaucomatous damage involves the macula. The anatomical basis of this damage can be studied by measuring the local thickness of the RNFL and the local thickness of the GCL layers on the macula. This macular damage is typically arcuate also, not only the RNFL, but also the one located on the macula. And here we’re talking about the macular vulnerability zone. This is a small region where a lot of RNFL fibers will go into the disc. So according to Donald Hood’s studies, most of the inferior region of the macula projects to this macular vulnerability zone, which is most affected during the glaucomatous damage. So we’re seeing this on this graph. Here is the more vulnerable zone on the macula. This is inside the macula. All these axons from all these ganglion cells will come into this small region of the inferior part of the disc. Also, outside the macula, the ganglion cells that are over here will take in their axons and go into this small region of the disc. The superior part of the macula is less vulnerable, because it will go into the disc on all these temporal quadrants, having a lot of space to have all the fibers going in. But outside the macula is different. It’s also outside the macula in the superior part, more vulnerable zone. So when we see slides from images like this, we can see the projections of these artifacts, or the defects of the RNFL on the ganglion cell layer. That goes in accordance to this study. So this is gonna be a little bit interactive. So I’m gonna ask a couple of poll questions for you. To keep this pretty interesting. This is poll question number one. What kind of defects shall we be looking at on the OCT to aid in the diagnosis of glaucoma? A, defects on the RNFL thickness and distribution. B, defects on the GCL thickness and distribution. C, arcuate-like defects starting on the macula and progressing into the optic disc. A and B are true, or A, B, and C, all of the above, are true. We’ll have a couple of seconds for you to answer this poll question. Oops. I’m so sorry. Okay. We have the answers here. All of the above. That is the correct answer. With this, we know that we do have to scan the optic disc, RNFL thickness, and scan the macula. The classic approach for this is doing a 9×9 or 6×6 scan on the macula, and another scan, 6×6, on the optic disc. You’ll have two separate scans. There is software right now from different brands of machines that could stitch this together. And then you’ll have a bigger scan. Others are working them separately. But there’s still wide scans and widefield analysis. Widefield is 9 millimeters here and 12 here, and you’ll get a big area of the posterior pole, where you could measure not only the segmentation for the RNFL thickness, and the GCL thickness that we were talking right now for glaucoma, but also for information about the macula. I mean other types of pathologies of the macula. This is a normal view of how a 12×9 wide topographic view looks. You’ll have here the en face edge that is set at 52 microns, where the thickness is shown. This is the thickness of the RNFL. This is the topographic view of the 12×9. You’ll have here a big B scan of the circumpapillary RNFL circle scan. So you can look if there is any issue on the segmentation of this image that is showing an artifact, and it’s not according to what we are thinking. The other interesting part of this is that here we have the macula. Since we’re having a lot of interest looking at the macula, we have the GCL profile of the macula. This is typical. Remember the first slides? When we talked about the typical assessment of the normal healthy macula? Normal healthy RNFL on this? This is how it looks like. Over here, we have probability plots. This is a simulation of how this will be on visual field testing. So if you have any type of abnormalities on the OCT, this will show on this simulation of this 24-2. Down here, 10-2, on the visual field testing. So this is normal. So let’s take a look at how it looks abnormally. Here you will see that on the en face image, the arcuate-like defects that we were talking about — if you see the topographic view, you will see the vulnerability zone affected in the superior quadrant. It’s outside the macula. And the inferior quadrant, it’s inside the macula. This is typically shown in glaucoma. Remember, these are the areas that are most affected. Superior outside the macula, inferior inside the macula. Then we have the classic defect of the ganglion cell layers. And it will show that typically, seen in the ganglion cell layer — remember this one? This is normal. Someone has taken a bite from the doughnut. You see that there’s something missing here. And this is the region of interest, where the ganglion cell layers are affected. So in the visual field, this will show an arcuate defect, superior and also inferior, on the 24-2, and also on the 10-2, because the defect is central to the macula. Remember on the visual field view, you will have the image of the macula upside down. There are some anatomical variations that could mimic some types of glaucoma-like topographic view. For example, this patient has the vessels shift — the blood vessels shift a little bit peripheral. So when we measured this, you will see this defect shown here, on the simulation of the probability map. But when we see the en face image, there is no arcuate-like defect. Nor on the RNFL topographic thickness. This looks like… The normal characteristics, and here the GCL classic doughnut also looks perfect. If we see the metrics, we will suspect that this yellow point and in yellow point — these are the positions of the blood vessels that are a little bit shifted. So how do we know this? In this report, these red lines will show the position of the normal blood vessels. You will see here the shadow on the RNFL takes into account blood vessels. It’s a little bit shifted, it’s a little bit moved. So when we compare this to the normative database, that’s why they plot out these types of defects. But this is not a real defect. You will have to see the topographic view that’s normal, en face image, normal RNFL thickness, normal GCL distribution also normal. So this is not a real defect. This is what we call Red Disease, because of the RNFL anatomy, and blood vessel shift. A little bit peripherally. There are variations also on the foveal anatomy. There is an interesting paper, written by Dr. Gus de Moraes, showing the individual variations in the foveal anatomy that shows some artifacts. This is what we have normal macula. Without any type of artifacts. And this is what we call a defect of the macula. It could be macular atrophy, it could be due to GCL diminishment in glaucoma patients, but also could be an artifact. And these artifacts aren’t shown. Gus De Moraes described almost 12 different artifacts, depending on the position that you take it. If the horizontal B scan is a little bit tilted or shifted, if the position of the head of the patient is a little bit changed, you will start seeing this type of artifacts on the macula. And these are due only to the position of the patient. So not always the defects that are shown on the OCT of the RNFL thickness are real. And not always what you see — the defects on the macula are real. What we have seen is an accordance between all these types of exams, to have a good interpretation of the results. So we are now coming to our poll question number two. Does variations on the RNFL and foveal anatomy reflect a problem on the correct assessment of these structures? A, yes, they always affect the metrics and results. So called Red Disease or Green Disease. B, sometimes they affect the metrics and the results, but this could be corrected. C, no, they never affect the metrics and the results. D, only RNFL variations affect the metrics, foveal variations are not important. Or E, RNFL and foveal anatomic variations always affect the metrics, but it is the clinician interpretation of the topographic defects which should be mandatory for the interpretation of the results. Let’s have a couple of seconds for you to vote. So we have the correct answer. 74%. The clinician should take the last opinion, interpreting the results. Let’s see some examples about this topographic analysis. This is the glaucoma patient with a classic 3D optic disc and 3D macula or GCL assessment. You will see the defects on the superior part of the disc. Here is this classical defect. We should know — remember, for the position, that this defect could be outside the macula. Because of the more vulnerability zone. Apparently the left eye doesn’t show any type of defect. The metrics are all in green. I don’t like that much the colors. Because we could mislead sometimes the diagnosis. But let’s say they’re all within normal limits. And when we see the ganglion cell layer, since this is a bigger scan, this is a 9×9, the first one that we saw on the optic disc was a smaller one, 6×6, the 9×9 will show the defect we were pinpointing on the other slide, going outside the macula. But also, having a small part of it inside the macular region. So that’s why on the ganglion cell starts, we’ll see this outside normal limits on the superior part. When we see the defect clearly, it shows what it is on the arcuate type of the defect. The other eye, it’s normal. You will see a thickening with the blood vessel. This is the RNFL thickness. And also in the macular region, it seems that there is not much going on there. The issue that we have to change between the one image optic disc and the macula to have the whole information — when we do have a widefield 12×9 bigger scan of this, we could see the entire defect. Coming into the optic disc. And also, this is the regular 9×9. This is the 6×6. When we stitch it together like I told you some machines do, we have this type of information. But even there, the scan size is not enough. With what is going on outside these limits won’t be taken into account. When we do a 12×9, we have a bigger scan. All this is taken into account, so we have a bigger area of information. This is the report that shows us the defect again, the en face images. And also on the topographic view, when we see the defect of the ganglion cell layer. It’s pretty noticeable. And when we do see the simulation or RNFL probability on the visual field test, it shows a classic glaucoma defect. Also when we go to the RNFL thickness plot, we could see that here is the part that is really — a lot of thinning in this part — in this area. This is the inferior part, and this is where the damage is. Let’s see another example of another glaucoma patient. Again. You will see the GCL starts with a lot of defects. If you see the quadrants here on the thickness map, the numbers, all the metrics — because they are so big, they could be within normal limits. Here is a defect that we were looking for, and it’s shown here. And if we see the macula is a lot affected, and this is the more vulnerability zone that we were talking about again, on the topographic widefield view, you will pinpoint clearly the defect. If we do the simulation… Again, en face image. Pretty clear. Here again, topographic view, pretty clear. Here is the defect on the ganglion cell layers, at the macular level. And this is the simulation where you could see the defects on the 10-2 and also on the 24-2. I’ve seen some questions popping up on the chat. I’ll address the questions at the end of the lecture. Don’t think that I’m not looking at them. We will go there. But not everything is glaucoma! So sometimes we have OCT scans that look like this. If we start looking at the numbers, at the metrics, and at the colors, we’ll see everything is red here. And there is a defect here from the optic disc that could be glaucoma. If we look at the macula, the macula looks so strange, so odd, this is not the classic view of the macula that we’re used to. We see a lot of defects here. When we saw the en face view, something is popping up there. So let’s take a closer look, what’s going on there. What’s going on there is that we have an epiretinal membrane. You could see all the lines. The epiretinal membrane is producing traction on this zone. On the B scan, it looks like this. You can see this epiretinal membrane. And this is — the report is an alteration of topographic views due to another type of pathology. This patient could have a glaucoma, could be misdiagnosed. OCT won’t give us a lot of information in this case. We do have visual field testing. Remember, this is a simulation. This is not a visual field testing. We should do visual field testing to compare and agree, and have all the different tests, intraocular pressure and the clinical and the history of the patients are always mandatory. So remember that not everything is glaucoma. We have to look at the macula. Not only for glaucoma, but for other important pathologies. And also, somebody has to be at the lower limits of the healthy controls. If we look at this patient and if we look at the metrics, all are in red. Somehow, the topographic view of the GCL — the doughnut shapes are normal. If we see here what’s going on, we have reds, reds, and reds. But we do have the regular hinged sign, thicker on the superior and inferior quadrant, and we do see here… It looks like there is some RNFL missing. But if it’s due to glaucoma, there should be something missing here. And there is not anything missing there. The probability maps show this. So what do we do in these cases? Is this normal? Is this a healthy control? Is this abnormal? Actually, this is a healthy patient that is in the lower limit of normality. So here the topographic view of the macula is normal, without anything wrong. A little bit less of RNFL thickness, but when we do on this patient visual field test, it looks normal. Also, an important data is in this arrow point — where are the blood vessel located — you have normal tissue. The blood vessels won’t pop up. When you have less tissue there, due to glaucoma, the blood vessels will pop up a little bit more. That’s an interesting biomarker to look at in the RNFL, when you have these. And as I told you, visual field tests. We did think when we started doing OCTs that we wouldn’t be doing visual field testing anymore, but that’s not true. We’re still doing visual field testing. It’s a functional test, remember. We will be doing this for a long time. So we do visual field tests of this patient. And it’s within normal limits. It’s the lower limit of the healthy controls. Remember to look… Everything should agree to diagnose the patient for glaucoma. The last example: It’s a defect of head and eye torsion on the exam. Here we’ll see normal, normal, normal, and there’s something here. And something here that we don’t know if it’s normal or not. If we reposition the patient and scan again, look. It disappears. And if you see down here… The image just shifts a little bit to the correct position. So the tilt of the head of the patient, the eye torsion, or anything like that, could affect this. And we will have these types of artifacts in the exam. We do need to correct this. Since we are not prone to do the examinations. And we just receive the reports, it’s hard to know when we receive the reports if the patient is on the correct position. So we could rely on the software to do this for us. Or we could correct this with post-processing afterwards, based on the anatomical positioning of the vessel, that is the nearest sign of this type of distortion. Let’s talk a little bit about glaucoma screening in post-COVID-19. This is the data from yesterday from the dashboard by the Center of Systems Science and Engineering at Johns Hopkins University. We have over 2.5 million deaths and… That’s a lot of people. 114,000,000 people dead from COVID. So glaucoma screening post-COVID-19… It’s really interesting. It was a survey sent to the Glaucoma Research Foundation ambassadors, that showed that only 3/4 respondents had a plan in place for reopening their offices after stay at home orders were lifted. This was held on May 8, 2020. They have three questions in this survey. Question one is: Are you still seeing patients in your office? Yes was the majority. But yes, only for emergencies is the second one. And this is interesting. Q2: Are you able to offer telemedicine options for your patients? Yes, video and phone. Telehealth options was 60%. Yes, phone only is only a little bit. So only a few people were prepared for this. How does this affect us as clinicians? How do we diagnose and follow up patients, chronic patients, with this? Home monitoring of IOP using self-tonometers is suboptimal, and it doesn’t have the accuracy we would like it to have. Visual field testing and OCT requires a proper setting and cutting edge technology to assure good reproducibility, and limit interexam variations. Plus home monitoring with this is not possible. Also, we have right now some OCTs that are portable, and they’re showing some promising results. Certain patient queries can be handled by phone. For example, a red eye or some sort of conjunctivitis or a surgically treated patient, if they have something worrisome, but it has limitations for following patients with glaucoma. Sometimes clinicians have been reluctant to embrace telehealth for many reasons. Patient safety, limits of the technology, training of the staff, conflicts of interest, there is a lot of different reasons. Innovative technologies can lead to improvements in care and decrease these disparities. Social distancing in the post-COVID era proves imaging machines are really valuable for managing patients. Robotic OCTs or portable OCTs with multimodal imaging, including color fundus capabilities make this task really possible. The functional visual assessment needs to be tested too. There are some studies being made in that field. There are some augmented reality software that you can use on your iPhone or on your phone, to have your eyes tested. But we need a lot more study in that part. It’s coming really hot on this glaucoma screening — not only glaucoma screening, but a lot of retinal pathologies — is artificial intelligence. So several AI techniques have been proposed to help detect glaucoma by analysis of functional and structural evaluations of the eye. The use of artificial intelligence has also been explored to improve the reliability of ascribing disease prognosis. So right now, we’re having a lot of different studies on artificial intelligence. We have to know that there are different types of artificial intelligence. An iPhone with Siri could be artificial intelligence. A Tesla self-driving car could be artificial intelligence. But we do have some more specific tasks. We’re talking about machine learning and Deep Learning technologies. Deep Learning has a lot of importance in medicine right now. And a specialty that has more Deep Learning studies… The more Deep Learning FDA approved machines is in ophthalmology. So these algorithms are managing a lot of data, and helping us to often outperform standards of global indices for expert observers. There remains no clearly defined gold standard for determining the presence and severity of glaucoma, which undermines the training of these algorithms. But we are going to be there. It’s time for poll question number three. Do you think artificial intelligence will play a role for managing the amount of images needed to review on the diagnosis of glaucoma? Yes, definitely. B, maybe at some point in the future. It needs more research and validation. C, I think I need more information about this. Artificial intelligence specific webinar would be nice. No, I think clinicians will still manage this information. E, I think it could help, but I’m concerned of the implications regarding patient data management outside a medical facility. Let’s have a minute to see the results. Okay. We have several types of results. One third think yes. One third think maybe. And one third think it could help, but I’m concerned about the implications. I agree with you guys. It’s a little bit overwhelming, what’s going on with this. But I think it’s a way we’re going through. So as we were looking… Managing glaucoma involves many reports with dozens of parameters, plots, images, a challenge a lot of doctors are facing. And we have visual field tests, OCTs, we have color fundus photos, we have these new topographic reports, we have the older topographic reports, we have several OCT brands, and there is a lot of information and we are concerned. So if only there was an easy way to manage all this information. This is really a problem right now. The amount of information produced by OCT and visual field devices can be overwhelming when evaluating patients in a really busy practice, in glaucoma and glaucoma suspects. Remember, we have to follow up all these patients also. So the needs: Efficient and effective software solutions to aid doctors in making quick diagnoses and stage of glaucoma would be really helpful. Identify progression in those patients where therapy has been insufficient. And guide the decision making processes. So right now what we are working on… We are having a lot of interest in developing this — it’s almost done, actually, in some countries, it’s available right now — is this glaucoma module. So in this glaucoma module, we’re working with this topographic widefield analysis, and what we have is the major concerns we have with the prior reports. The first one: How do we aid and avoid the head rotation or any sort of artifacts? The software is taking into account this, and we can assess the correct position of the blood vessels and have the correct positions of the scan, to avoid all these types of position misalignments and taking into account too some types of errors during the diagnosis. We do have the same topographic view for the ganglion cell layer. It’s really important at the macula. We have the simulation, visual field testing points. But also right now we do have integration with a lot of different visual field test machines. Where we could import directly from the visual field test machine, and have the real examination here. So not only is the simulation based on the OCT, but also visual field tests, where you could see the agreement with the simulation visual field testing points. This takes into account not only for one single view, but also for follow-up. We could follow up the patients and compare between topographic view, between ganglion cell layer view, between the color fundus and the visual field testing right now. This is interactive. We could select different exams, we could compare two exams. We could enlarge image, we have multimodal capacity, and this is driven by artificial intelligence that could help us find the correct positions. So there’s a lot of information on this report. And we do have a lot of the different tests that we have on just a single view, that makes our life really easy. This is how we could start repositioning the macula or the scan, the B scan, so we could flick from this switch and place it in the correcting position, where we’re talking about, to avoid the different types of images that are not correct. This is a trend analysis view. We could do trend analysis. RNFL, GCL, the topographic views, IOP, trained on the visual field with the pattern deviation, and the topographical also. We can see a trend graph with every information that we have, or every test, regarding the brand of equipment that you’re working with. So it’s really, really very helpful. This is how the report looks like. You will have the correct image right now. And also the topographic views that we were talking about. So it’s time for the last poll question. Do you think this OCT topographic approach to the diagnosis of glaucoma is better than the classical metric derived diagnosis? Yes, I would like to start evaluating my patients with this method from now on. B, it’s an interesting approach, but I would also use the metrics. C, I would consider evaluating my patients based on this method. D, no, I prefer using the metrics and the classic 3D scan reports, because I’m more used to them. Or E, I would consider also the metrics from the optic disc head parameters, like rim, cup to disc ratio, and other parameters. A couple seconds for finishing the voting. Okay. So yes, 20%. It’s interesting, but have the metrics. 24%, interesting. 16, I would consider. A lot of people are used to the classic reports — only 1%. And 40% need information from the optic disc head parameters. So it’s good to have all the information we need in one place. I would like to have IOP testing. I would like to have topographic views. I would like to have corneal assessment, to be sure that the thinning of the cornea, other pathologies, won’t affect these measurements. The last thing that I will be looking through are the metrics. Because metrics… It’s proven it will give us sometimes wrong diagnosis — I will look at the metrics to take an agreement of everything that I have been looking through. But it’s not my primary concern. So in conclusion, the integration of different diagnostic tools under a single user friendly platform seems to be the logic approach to managing lots of data in pathologies such as glaucoma. Science and technology are already present in daily life and clinical practices. These innovations offer significant improvements in patient flow, outcomes, and reduce health care disparities. When you’re working with a single report and have all the information together, the workflow in your clinic — it really helps a lot. And right now, since we’re not… We’re having all these types of restrictions due to COVID… Having this is really interesting. Artificial intelligence has the potential to revolutionize the screening, diagnosing classification of glaucoma, both through the automated processing of large datasets, as we’ve been seeing, and by early detection of new disease patterns. So in addition, artificial intelligence holds promise for fundamentally changing research aimed at understanding the development, progression, and treatment of glaucoma, by identifying novel risk factors, and by evaluating the importance of existing ones. We thought a couple of years ago that this would be the future. Due to restrictions — due to COVID, it’s now the present time. This is my last slide. This is my email. If you want to reach me with any questions… And we do have some questions from chat. I’ll try to address as many as possible right now. So the first one: Is thin cornea a risk factor for glaucoma? Yes. It is a risk factor. Not for glaucoma, but you could have errors in the intraocular pressure taken. IOP. Could be a little bit wrong, when you have thinner or thicker corneas. And also, it could affect the OCT scans. More the curvature than the thinning, but it’s something you should take into account. Glaucoma affects peripheral region or central regions? If you’re talking about the visual field testing, glaucoma effects start in the periphery and finish on the center. If you’re talking about the OCT, the macular vulnerability zone, the region where it all starts on the inferior part of the macula that takes into account the smaller region, where all the fibers go into the optic disc. So… It depends. If it’s on the visual field peripheral, if it’s on the OCT, it starts centrally. What is this blue color? I’m so sorry. I don’t know what that blue color is. I couldn’t answer that. How optic disc is affected in early stages of glaucoma? Well, optic disc is affected in early stages of glaucoma… The first thing that you should look in early stages of glaucoma if you have an OCT is the macula. If you don’t have an OCT, and you’re just looking at the disc through a loupe, or you’re doing an indirect ophthalmoscope, you have several biomarkers that you could look at the disc, like cup to disc ratio, like the vessels, how they’re going, if you have some vascularization on the disc. Clinical is always mandatory for this. What machine did you use for these Hood analysis reports? Hood analysis reports are available in two machines. The top cone one, both of them, spectral domain, that’s called Maestra II, and also the OCT that’s called the Trident. And it’s also available on the Heidelberg spectralysis machine. The new version of it. Which one is more important and meaningful in assessing cup-to-disc? Vertical or horizontal? Cup-to-disc vertical is more important. What you see is that the more… The macular vulnerability zone — they go in through the disc on the vertical axis. You will see diminishing of the cup to disc ratio inferior in early glaucoma. Then superior. And definitely vertically is the axis that you should be looking at. What is the relation between IOP and optic disc in regard to glaucoma severity? Well, IOP, it’s always one of the paradigms of glaucoma. IOP that leads into the optic disc damage. Right? So it’s a relation. Remember, there is also normotension glaucoma. So it depends actually on several anatomic features of the disc. What is the use of number on matrix? You’re talking about FDT technology? FDT technology is a good way to test the visual field. It will be — you could have visual field defects earlier than on a regular white to white 24-2. We use that in the clinic I’m working in right now. We still use that. So I think double frequency technology also has importance right now. In case three, is the scan not decentered with blood vessels slightly away from the reference? I think case 3 was exactly the example of that. With topographer is best for glaucoma field and wide field examination? We’re talking about tomographers here. This is OCTs. We do have topographers for the disc. Disc topographers are not being used that much right now. We do prefer using OCT, because OCT will give us direct measurement of the areas of interest. While the topographers will show the difference between the reference plane and the elevation with that plane. We used it. Some people use it a lot. But I sincerely prefer working with OCTs. I want to know when a young patient has 0.5 and 0.4… I think I will respond to this… I’ll type my answer. Because it’s a clinical case for Samina. Have you tested Cybersight artificial intelligence service for glaucoma? No, I haven’t. Sorry for that. I will do that right now. Is there a diagnosis of glaucoma suspect? Or is it a term not used in glaucoma investigations and management? Glaucoma suspect… Yeah. It depends, actually, on how many tools do you have available. If you had a lot of tools, you should always go and look for the correct terminology. And try to find the answer. Glaucoma suspect… If you have a patient that had intraocular pressure elevation and it has a family history of glaucoma, he or she is a glaucoma suspect, but there you have to do the test, and when you do all the tests that you have available, you should arrive to diagnose. And even though you have some sort of doubts, then you could always ask the patient to come for a second visit, and see if there is any change between the baseline and the second exam. If 24-2 is full but OCT shows some loss of RNFL how often would you ideally repeat tests to show preperimetric progression to diagnose glaucoma? Every 2 or 4 or 6 months? Okay. If 24-2 is okay, but OCT shows some loss and you’re certain that the OCT image is well taken, then I will agree with the OCT. How often do I repeat? Every six months or every year. If the patient is well controlled. Every year is enough. If it’s the first time you’re looking for, or you have any type of doubt, as we were speaking, every six months would be nice. Are there studies that have shown the specificity of widefield analysis in very early glaucoma? Yes, there are. Dr. Donald Hood and Dr. Gustavo de Moraes, they have done a lot of work in this field. There are about 10 to 15 papers that were presented in ARVO last year. 2019. 2020 was suspended due to COVID. And there are a lot more studies that will be shown on ARVO this year. So if you are interested in this, there will be a lot of new studies coming out. How do you find MRF field test, which is an online test compared to Humphrey Perimeter? I’ve never used the MRF field test. So I couldn’t answer that. Please explain the two visual field reports on the Hood report? There are visual field simulations. What you’re looking are the same points that are tested on the 24-2. That’s the big superior one. And on the 10-2, that’s the inferior one. So what we are looking are: How the structural changes on the macula or on the disc affect the localization of these points. So due to this thinning of these areas, if you have inferior thinning on some part, you will have the same correlation on the visual field test. Are there any reasons why inferior arcuate of macula is more prone to be damaged in glaucoma compared to superior arcuate? Yes, there is. Let me show you. I think if we go back here, it will be easier to understand that. I’ll try to find the correct slide. This is the one. So anatomically, all the ganglion cell layers that are here… Will go into the disc, the inferior part of the disc, but not the whole quadrant. You see? It’s less than a third of the quadrant that takes into account for all these areas. All these ganglion cells will be like… Trying to go into Tokyo Metro in rush hour, or New York City Metro in rush hour. You see a lot of people going through small entrance. That’s what you see here. A lot of fiber is going through a really small entrance. If you see the superior part of the macula, it’s less vulnerable, because all this area will go into the temporal quadrant. That’s the papillomacular bundle. A lot of this here… On the superior arcuate part that comes here. That being said, there’s a more vulnerable zone outside the macula on the superior quadrant, due to the same effect. A lot of fibers coming through a very thin space. That’s why… Here for the inside macula… Inferior here for the outside macula. And superior here for the outside macula are the more vulnerability zones. We’ll go on with the questions. We do have some time. We have five more minutes. Visual EP helpful for early diagnosis? I don’t know that answer. What is VEP? I’m so sorry about that. Can VEGF be related to glaucoma? Haven’t read anything about that, but it’s a really interesting question. I’ll try to look at that. And be back with an answer for you. I really don’t know right now. What’s meaning -2? In 30-2… Oh, okay, okay, okay. What’s the meaning of “-2”, in 30-2, 24-2, 10-2 — the number of times they spot the locations of points they have. 30 degrees, 24 degrees, 10 degrees, and 2 stands for the number of points that are being tested. Please guide about the disc… I’m sorry. The disc v scan on Topcon? Please guide about the disc v scan on Topcon? I’m so sorry. I don’t know what you mean. I could type the answer if you explain a little bit more to me. Thank you. Miguel. Recommend the same doctor realizing the artifacts… Yeah. The same doctor, the same technician, if that’s not possible, be sure to train them as best as possible. And make sure that they are aware of these types of defects. And sometimes if you are an experimental reader, you can look at the reports on the exams. It’s always good to have a review station where you could go through all the B scans. If that’s not possible, you could spot some of the defects on the scans. But it’s more advisable to have the doctors or the people taking the exams to be… Really, really good on this and spot these types of abnormalities. Does a normal IOP mean there is no glaucoma? No. There is normal tension glaucoma. Considering glaucoma diagnosis, which of the reports should we give more attention to? Between Hood report and visual field? Especially when there are differences between them? You have to look at both of them. You have to look at the visual field. You have to look at the Hood report. You have to look at all the history and all the data. You have to look at all the information that you have. And the more information that you have, the more assured you’ll be with your diagnosis. The Hood reports help us a lot. You have a lot of different information in just one single report. When you are really used to looking at it, it will help a lot. But I do always look at the metrics. The other reports, the optic disc, and the visual field tests. Which test is more reliable to confirm glaucoma? Visual field test or OCT findings? Okay. So there is preperimetric glaucoma, where you won’t see any defect on the visual field. There you could see defects on the OCT. If it’s more advanced glaucoma, we do prefer to follow up patients with visual field testing. Instead of OCT. Due to the floor effect, when the RNFL reaches a level that is so low, then we couldn’t use that to follow up patients. We could use the macula. So take-home idea — look at the macula on early glaucoma. And look at the macula on advanced glaucoma. That will help a lot. But always look at visual field defects too. Thank you very much. Thank you for attending. The maximum attend of webinar is Asian. Oh, thank you very much. Kindly give us a few points for ganglion charts of OCT. How should we consider while managing patients. Okay. That will take a little bit more. I think we have three more minutes. I can type the answer to you, Samina. Thank you very much for your question. Are we going to get visual field indices on Hood report? Yes, we’re going to get that soon. We’re working on that. Hopefully really soon. Which test is more reliable to identify glaucoma? That’s a hard one. I mean… I think… Again… The more tests that you have, the more information that you get, the better you get the diagnosis. But that’s not always necessary. There are always clinical findings — always are mandatory. Always start diagnostic aids. But you should start with a clear suspect of this. So which is more reliable? Hard to say. We rely — all of them, if you do it yourself, or you rely on the presence of them. For glaucoma diagnosis optic nerve along with macula monomap is required? You can do it on a 12×9, wide scan, or a single. Either way would work. If you do it two separate ways, you will have more work to do. If you have the single view, it will make your life a little bit easier. When you have a lot of patients that… Always it’s helpful. Relationship of corneal thickness is important? Yes. We already addressed that. Can Amsler be done instead of 10-2? You are looking for different pathologies. Amsler will help you with macular pathology, but will not help you with glaucoma. What about there is an issue of narrow angle in this case? We’re unable to view the macula in undilated pupil. That’s right. If you have narrow angle… Well, if you have narrow angle, you can do several other examinations. You can do gonioscopy to assess that. Anterior segment OCT if you don’t have that. You could use a 90 diopter lens for the disc, or if you have cameras, you can use an artificial intelligence aid right now, so you could take a picture and send the picture to the software and the software will do the reading for you. There’s a lot of ways to do that. Thank you! I think we’re finished with the questions right now. Thank you very much. For being here. It was my pleasure, again, to be with you. Thank you for your attendance.

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March 4, 2021

Last Updated: September 12, 2022

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