I Take Comfort in Greater Certainty
By Glenn S. Corbin, OD
Dr. Glenn Corbin from Wyomissing Optometric Center and Dr. Greg Jackson from MacuLogix pose with the newly delivered AdaptDx Pro headset, the second-generation dark adaptometer developed by MacuLogix.
A 2004 study showed that up to 78% of AMD patients had substantial, irreversible vision loss at first treatment.ii That statistic could either terrify me as a doctor or give me an excuse to feel helpless. I chose neither. Instead, I resolved to make sure that my patients fall on the minority side of this statistic and I succeeded. I credit this to our practice’s adoption of dark adaptation.
In 2014, our practice installed the first commercial dark adaptometer ever sold. The AdaptDx® is a functional testing device that has been shown in clinical trials to identify patients with the earliest signs of AMD even when they have no other structural signs of AMD. It does this by revealing impaired dark adaptation function associated with AMD at least three years before it becomes clinically evident.ii
The past seven years of using dark adaptation testing in my practice has completely changed my outlook on this potentially visually devastating disease. By proactively monitoring for both structural and functional changes in my AMD patients, I am able to catch CNV much earlier. As a result, I’m able to refer my patients with advanced AMD to my local retina specialists for treatment while they still have good BCVA in BOTH eyes. We have several cases of patients starting anti-VEGF treatment while maintaining 20/20 and 20/25 vision.
What’s There and What Does It Mean?
You might ask, “why would we need an instrument to give us more information about what we routinely look for in a dilated exam?” The short answer is: we’re not perfect. A 2017 study published in JAMA Ophthalmology revealed that optometrists and ophthalmologists failed to diagnose AMD about 25% of the time.ii
Identification isn’t the only challenge. Until the commercialization of automated dark adaptation testing, our ability to characterize small drusen was limited. We might know they were there, but we didn’t know whether they were harbingers of AMD. Several peer-reviewed studies have shown that dark adaptation function is impaired from the earliest stages of AMD, with increasing impairment as the disease progresses.ii Much like glaucoma detection and management, having both structural and functional assessment of my AMD patients enabled me to vastly improve my ability to confidently diagnose disease and monitor progression.
Ignorance Is Not Bliss
Before bringing this technology into my practice, I would see patients with some small drusen but I would be unable to deliver a definitive diagnosis of AMD. But now, when my structural testing reveals something mildly suspicious but seemingly innocuous, I can turn to the AdaptDx Pro® to confirm the diagnosis. Conversely, if dark adaptation is normal, I have greater confidence and worry less about the patient’s prognosis over the next 12 months. We’ve accepted uncertainty for so long many of us have gotten comfortable with it, when in truth, it’s not acceptable. The answers are there and we now know how to obtain them. This is why I’ve long maintained that every optometrist should use dark adaptation testing in their practice.
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Practical Implementation of Dark Adaptation in Optometric Practice
This resource goes beyond explaining why dark adaptation is so important in optometric practice. Having already established the reasons why functional testing is essential, this year’s report outlines the practical strategies for how to make routine testing a reality in your own eye care practice.
About the Author
Dr. Corbin earned a B.A. in Biology from Hofstra University in New York, and a B.S. in Visual Science and O.D. degree from the Pennsylvania College of Optometry. Dr. Corbin owns and operates the Wyomissing Optometric Center in Pennsylvania. He serves as Chief of the Section of Optometry at Penn State Health St. Joseph Medical Center. He is also on the Allied Health Medical Staff at Penn State Health St. Joseph Medical Center (inpatient consults and Emergency Department eye care) and serves as a Consulting Staff member at Health South Reading Rehabilitation Hospital. Dr. Corbin serves as Principal Investigator for numerous pharmaceutical companies in conducting clinical trials to test new medications and devices. He is recognized for his lectures, both locally and nationally, and has authored numerous professional articles and contributed to several textbooks. In 2014, Dr. Corbin was selected as the “Pennsylvania College of Optometry Alumnus of the Year” for his contributions to Salus University/PCO and the profession of optometry.