AdaptDx: Helping Fight AMD
Damon Dierker, OD, FAAO
Dr. Dierker explains how Eye Surgeons of Indiana uses the AdaptDx® to screen patients at risk for age-related macular degeneration (AMD) as well as verify the diagnosis of AMD in more advanced cases.
I practice in a referral center setting, optometrists and ophthalmologists working side-by-side. I see approximately 150 patients per week. There are more than ten million Americans with macular degeneration. Most of these patients are seeing optometrist for their primary care eye needs.
AMD Is Discovered Too Late
What we still fail to do as a profession is identify people with earlier stages of disease and become proactive in preventing vision loss, rather than just reacting to patients once they’ve actually lost vision. And it’s amazing that 70% of patients in clinical studies have been shown to not have a diagnosis of AMD until they’ve actually lost vision in one eye.
That is not acceptable in terms of what we can do to help these patients going forward. Fortunately we have tools, such as the AdaptDx, to help us understand which patients have risk for vision loss in the future and identify patients even before we can see clinical changes with our fundus cameras or with our condensing lenses.
A Stress Test for the Macula
When I explain dark adaptation tests to the patient using the AdaptDx, I use an analogy that this is a stress test for your macula. They understand that. I tell them:
“I’m going to flash a light and we’re going to see how long it takes for your macula to respond to that light. And if it takes long to recover, we know that there’s a problem. You may have normal vision, you may have a nearly normal fundus, you may have no symptoms at all. But we know there’s a problem.“
AdaptDx Is 90% Sensitive and 90% Specific
One of the great things about the AdaptDx is that it’s a very straightforward test to understand as a practitioner. It’s basically a yes-or-no test. If somebody has impaired dark adaptation, which means their ability to recover from a bright light takes longer than 6.5 minutes, we know with 90% sensitivity and specificity that that patient has macular degeneration or perhaps macular dystrophy. If their dark adaptation is normal, we have confirmed normal retinal function and, in essence, ruled out macular degeneration in that patient.
I like that AdaptDx is very versatile and what it can do for your practice. I use it in two ways:
- I use it to help diagnose and verify that somebody has age-related macular degeneration or macular dystrophy if the clinical findings are unclear.
- Additionally, I use it as a screening tool with a patient self-pay model to identify patients that have risk for AMD but do not yet have clinical signs.
Early Detection of AMD Saves Vision
We know as many as 20% of people over the age of 60 will have impairment in dark adaptation prior to having any definitive signs of clinical macular degeneration. With the AdaptDx I’m able to identify these patients and take action before they lose vision. It’s our goal as optometrists to take care of our patients and prevent vision loss. The AdaptDx is helping us do that for our macular degeneration patients.