Advancements in the Management of Macular Edema following Retinal Vein Occlusion - Episode 2
Comprehensive insight on optimal work-up and diagnostic testing for patients with retinal vein occlusion.
Rishi P. Singh, MD: Before we get into further treatment discussions about the visual examination and what you might do, is there any role do you find for OCTA [optical coherence tomography angiography] with these patients? Or what things on the clinical examination may you tell your trainees or even your colleagues to look out for that might be helpful to them?
Jayanth Sridhar, MD: That’s a great question. I go back to basics, visual acuity at baseline, that’s the most defining prognostic factor, and that may give you a clue, as you referenced, getting angiograms on those patients with worse vision loss. They may give you a clue that this patient has more of an ischemic occlusion than a nonischemic occlusion. That ties into checking for an afferent pupillary defect. Again, this is going back to basics, but if you work in an office or you work with a team where you aren’t checking the pupils, it’s helpful to have an accurate pupil exam, because that also gives you some idea of risk and prognosis. On the actual exam, it’s helpful to look on your fundus photos or your fundus exam for a concomitant arterial occlusion. It’s uncommon, but sometimes you’ll see a joint arterial and venous occlusion. We think that the reason atherosclerotic disease is tied, going back to the mechanism, is that there is that arteriovenous crossing issue, and that may contribute to the vein occlusion.
Then in terms of OCTA, I’m curious what you do, Rishi. I find that OCTA can be helpful because, unlike fluorescein, it can show you layer by layer what’s going on with the vasculature. Fluorescein has its great strengths, but one of its weaknesses is if you have anything on a superficial layer, it can affect your ability to assess steeper layers, and the hemorrhage issue is what we talked about earlier. That being said, I don’t know if OCTA generally changes my management at baseline, it may change my prognosis. Sometimes if you get an OCTA at baseline and the foveal avascular zone [FAZ] is significantly enlarged, then that changes the conversation with the patient about what to expect. But I don’t find myself doing it routinely. I’m curious about your experience though.
Rishi P. Singh, MD: OCTA is for those subtle cases, let’s say Jay, you get presented with a case that has an essentially normal looking fundus picture. Very few hemorrhages, if at all, say your patient is diabetic as an example, with a mild to moderate amount of macular edema, or no macular edema at all, but vision loss. And you’re trying to tease away whether it’s diabetic macular ischemia, is it vein occlusion and ischemia as a capillary dropout? One of the ways that OCTA has helped me differentiate those is that I can see collateral vessels. Collateral vessels are very important to see in some patients, and that can be this hallmark or the sine qua non of having a vein occlusion present without the most subtle of signs. Many of us see patients in practice, and they may have had cataract surgery recently, there’s a whole confounding list of things that can cause macular edema. We’re trying to pinpoint them for mainly academic senses, but also maybe for treatment, depending on the situation. Obviously, if a patient had cataract surgery in the recent past, and you’re worried about that being the cause of the macular edema, you may treat it differently than if you had vein occlusion-related macular edema, for example.
OCTA has been helpful to kind of localize and evaluate collateral vessels, and then that way, it’s been helpful to then determine whether I’m going to go with an anti-VEGF or steroid option, or potentially on the topical side for a cataract-related macular edema option. That’s been the way I’ve been using that in practice. I don’t typically get fundus photography, but I understand where you’re coming from, from that standpoint. It’s a good option to show patients what they’re like, how they’re doing, and how they get better over time. Let’s talk about the longitudinal patient. Is it always OCT [optical coherence tomography], or do you throw in fluorescein when you need it? Or when do you figure out if fluorescein is needed as you go longitudinally with the patient’s course?
Jayanth Sridhar, MD: That’s a great point. For me, I use OCT essentially at every visit, for us and retina [specialists], that’s our bread and butter. That’s almost mandatory as part of our exam, and especially if you’re tracking these patients either for treated macular edema, or just to assess for development of macular edema, because it can happen later, especially if you see them acutely in the process. I use OCT on every visit. Fluorescein, there are 2 scenarios where I’ll consider fluorescein. Let’s say I did not get one at baseline, I may get one down the line. Let’s say the vision has continued to improve, but then it stalls at some point at a vision that we’re not super happy about. We talked about the utility of OCTA to assess the FAZ. Fluorescein can do the same, and then can give you more information about what’s going on with the retinal periphery, because besides treating the vision loss from the vein occlusion, we also want to be cognizant, we want to prevent future complications of the vein occlusion, such as neovascularization that we could treat.
The other scenario where I’ll go to fluorescein is if there’s a drastic change in vision. I see a small subpopulation of these vein occlusions, where it’s almost like they get a second occlusion later. They’re doing well and then all of a sudden, they’ll come back with more hemorrhages, their vision drops. And I think that’s a scenario where I will repeat a lot of the imaging, including the fluorescein, to get a sense, “OK, what is going on? Has something progressed? Has something come back?” That’s not most of our patients, but I do find, again, a small percentage of our patients where they may experience what you’d consider perhaps a second event.
Rishi P. Singh, MD: That’s great. Fellow eye disease, we talked about this just a moment ago. Obviously, there’s clearly a risk for the fellow eye involvement. What is the counseling that you give the patient about fellow eye involvement in these circumstances?
Jayanth Sridhar, MD: We know that the fellow eye has risks, that’s a common question patients will ask. Oftentimes the fellow eye is the better-seeing eye and will remain the better-seeing eye. I tell patients that it’s not the most common scenario. I don’t think most of our patients with vein occlusion get a significant vein occlusion in the other eye, but this is where I go back to talking about systemic risk factors and risk factor modification. If they don’t have a primary care physician, which sometimes is true, plugging them in to see a primary care physician. If they aren’t on medication, getting them on medication for their high blood pressure, getting worked up for hyperlipidemia, getting worked up for diabetes. Sleep apnea is another thing that I will talk to patients about. We don’t think or talk about it enough, but obstructive sleep apnea can definitely contribute to vascular disease in the retina. Those are the big things.
Now, there’s a bimodal distribution to retinal vein occlusion. There’s a smaller group of patients who are younger. We say that a lot of times younger patients present with retinal vein occlusion, and that’s where we start thinking about some sort of laboratory work-up, to again assess for risk factor modification. I’m curious Rishi, there’s a lot of debate about what laboratory tests to get in the patient who doesn’t have let’s say, age or vascular risk factors. How do you assess what blood work to get? Because I feel like you can order 100 tests, or you can order 10 tests, and I’ve seen people be anywhere within that range when I talk to experts.
Rishi P. Singh, MD: First and foremost, I think the data for those aged 55 and less show that we have to evaluate them for these systemic coagulopathies as you’re mentioning. The problem is that the vast majority of studies have shown that they’re very futile in determining anything that’s of a meaningful nature. I remember one paper that was published from the Retina Group of Washington that looked at this with regard to what the value was of those aged less than 55 and ordering systemic testing. The answer was it gave a result in about 20% or 30% of patients, but realistically, there were very few action items that were taken other than systemic aspirin therapy, or potentially other anticoagulation therapy in rare cases. I do order the testing myself. I don’t send them to hematology. I’m comfortable with the laboratory we have here to order things like factor V Leiden deficiency, protein C and S, a CBC [complete blood count] to check on hypercoagulable states, hyperhomocysteinemia, anticardiolipin antibodies, things like that, that might be a concern.
Those are the standard laboratory things that are done. But again, some of these come back and then they require some more detailed analysis, because when you order these tests, hematologists can thenunderstand the titers better than you, or the results better than you and I. I tend to curbside them after ordering these tests, and say to them, “Hey, I’ve got this patient. I have this situation. What are your thoughts on this?” But I can totally see why people might refer these patients out to their hematologist or primary care doctor with a litany of tests to order, and then to interpret and get.
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Transcript edited for clarity.