Patient Communication Regarding Visual Function in Geographic Atrophy

Eleonora M. Lad, MD, PhD: Jay, do you measure function in patients with geographic atrophy [GA] as the disease progresses?

Jayanth Sridhar, MD: This is the most important thing to our patients, right? They want to know how they’re progressing and if they are getting worse. This is one of our big unmet challenges with macular degeneration, especially dry macular degeneration and geographic atrophy. We have visual acuity usually measured on a Snellen chart for our clinic visits, or some sort of formalized, standardized chart for clinical trials. Visual acuity is probably our best measure of visual function, but it’s probably not the best way to capture all the things patients experience. We know they have reductions in contrast sensitivity, problems with reading in low light, and people talk about low luminance measures. Those aren’t measures we’re using in our clinical practice every day, so I’m curious what the rest of you all think. I think this is an area where we must improve in terms of finding better ways to measure visual function.

Nancy M. Holekamp, MD, FASRS: Jay, you mentioned that visual acuity is our best way, but it could also be our worst way, because patients with GA sometimes have foveal sparing, where they can pick out a letter on the eye chart. They may get all the way down to 20/25, but they’ll tell us that they can’t read comfortably, that they’ve given up reading for pleasure, or that they are no longer driving. There’s this disconnect between what they can pick out on an eye chart and what they’re experiencing in their everyday life. Many visual changes that are chief among the complaints of these patients aren’t being picked up in the office, and contrast sensitivity is a part of it, but we don’t routinely use it. Dark adaptation is hard to measure, we don’t routinely do that in clinical practice. The best thing to do is to listen to your patients and to hear what they’re struggling with. I’m frequently referring patients to low-vision specialists to get aids for both reading and daily life.

Jayanth Sridhar, MD: I love some of the points you made. One of the things I try to do, and I’m curious if you guys do this too, I try to note down not just the line they read down to, but how they see that line. And I train our staff to write if the patient was searching for those letters, or if they were moving their head around to find that fixation point to read those letters. I think that matters a lot, because that will tell you more about their functional status, versus just that they’re seeing 20/30 on an eye chart. There’s a very big difference between 20/30 looking at 1 fixation point versus multiple.

David R. Lally, MD: I would agree with all that’s been said and add that I’m more concerned in my day-to-day clinical practice with my patients with geographic atrophy, when they’re coming to our office, not what their visual acuity is on the eye chart, but the symptoms and what the patient is telling me. I’ve learned over the years that patients give you the best information, and when they say that things are getting worse, they typically are. A patient with bilateral nonfoveal GA may be coming in every 6 months for years with 20/25, 20/30 vision that’s not changing on the eye chart. But every 6 months they come in and you hear them complaining more, that it’s getting harder to drive and see the street signs, and they stopped driving at night, these sorts of things that we do not pick up on our functional testing in our routine clinics.

Eleonora M. Lad, MD, PhD: These are outstanding points. I’d like to add one more thing, there is a test that will likely be increasingly used in our clinics, which is microperimetry. There’s a CPT [current procedural terminology] code for it, similar to visual fields, and it might give us a sense of how advanced the disease burden is in terms of scotomas or blind spots.

Transcript edited for clarity