Presentation and Diagnosis of DME and AMD

Carl D. Regillo, MD, FACS: Blake, can you tell us about how patients with DME and neovascular AMD typically present?

Blake Anthony Cooper, MD: Sure, absolutely. Carl. So it's important to understand that typically these are different patient populations that we're seeing, and oftentimes for diabetic retinopathy and diabetic macular edema, patients may actually be asymptomatic and may not realize that they actually have diabetic retinopathy occurring. And so that's part of the reason that it's extremely important to make sure that we encourage patients to have annual eye exams. But oftentimes when they do start having symptoms it's typically general blurring of central vision. Oftentimes with age-related macular degeneration, it can also be asymptomatic in the early stages. So we tend to break macular degeneration down into a dry form in a wet form. Essentially, what we mean is an area of atrophy or loss of cells under the retina that can weaken the way the photoreceptors function and work. Occasionally, blood vessels can come up through those areas causing distortion and blurring with their central vision. So often patients will come in with loss of vision and one or both eyes. But again, it's important to understand that they actually may be asymptomatic.

Carl D. Regillo, MD, FACS: That's a very good point; or they don't think the symptoms because they can be somewhat subtle, especially early on when we want to detect them. They may not think of them as a significant retinal problem.

Blake Anthony Cooper, MD: Correct.

Carl D. Regillo, MD, FACE: Dave, how does DME and neovascular AMD progress over time?

David R. Lally, MD: In both of these conditions, if the fluid is left untreated, the retina's not happy, to put it simply. The natural state of the retina, and the macula fovea in particular, is to have no fluid within the intracellular or extracellular spaces in that region. And so, if fluid is left untreated in diabetic macular edema, what we typically see is, over time with the chronicity, that these cells will start to die. And that includes photoreceptors, Muller cells, and a lot of other cells in the retina. And so, we want to get after treating that edema early. If we look at neovascular AMD and that fluid and exudation left untreated, we really worry about the development of fibrosis over time, where we actually see fibroblast and we can also see the development of atrophy where the RPE and outer retinal tissue starts to die.

Carl D. Regillo, MD, FACS: There's no doubt about it that chronic progressive disease leads to irreversible neurosensory function. It is in essence central nervous tissue. So it has a limited ability to recover from these pathologic processes. Mike, what is the clinical benefit with early detection of either DME or neovascular AMD?

Michael A. Klufas, MD: Great question. We have a lot of studies that show if someone presents with better initial visual acuity and we treat exudative neovascular age-related macular degeneration earlier, there's a higher chance of staying within that visual subgroup. That doesn't mean to say that someone who presents with poor vision won't gain vision and many of our patients do, but all of us have seen patients who may have been depending on their other eye and they come in with a scar and we initiate treatment. But there isn't a great visual gain that we would like if we had started treatment sooner. I think looking at the diabetic macular edema studies comparing some of the older ones where there were sham treatments or even focal laser people lost vision, whereas when they were crossed over to the injection group, there was gain a vision. So for that type of condition where there could be continued gain over several years, five years or greater, it's always good to see the treatments start earlier to allow those visual gains happen sooner for those working-age patients as well.

Carl D. Regillo, MD, FACS: Like most things in medicine caught earlier: better results, and sometimes even easier to treat. And I find that with the DME group in particular, may be less treatment to get them good again, get them into better vision range and the data very clear caught early, better absolute vision outcomes and wet AMD in particular. If we catch wet AMD when the vision acuity is good, 20, 40, or better, we can keep it 20, 40 or better in over 90% of patients for even several years. Very powerful statistic.

Michael A. Klufas, MD: The analogy of the swimming lanes in AMD is a good one. If you can get you in the early lane, where the vision is good, there are people who switch lanes, but if we can keep you in that early lane, that can be very helpful. And even in DME, we've all seen cases where there are exudates that are encroaching on the foveal. And if we catch that earlier, usually patients don't have exudates. They don't have the vision loss and so it's nice to be able to offer the treatment earlier to our patients.

Carl D. Regillo, MD, FACS: One more thing. We know that chronic retinal swelling in the center of the macula is harmful because for chronic edema in particular, whether it be DME or neovascular AMD, the amount of vision gains or absolute vision outcomes are not as good.

Michael A. Klufas, MD: Good point.

Transcript Edited for Clarity