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Abnormal dark adaptation: An early biomarker for AMD
A recent Medscape report concluded that physicians are spending half of their office work day hours engaged in nonclinical care – time spent tinkering with EHRs, deciphering HIPAA requirements, battling over insurance claims and securing prescription preauthorization.
While the stark reality of practicing medicine today, it is a disturbing trend, disturbing in that these “extracurricular” activities sap precious time from patient care. This is time that could be otherwise spent in direct patient care, keeping abreast of current literature and, perhaps most importantly, advancing our understanding of certain clinical conditions, such as abnormal dark adaptation (DA).
Abnormal DA is both common and confusing, as evidenced by the frequency with which patients ask: “Doctor, why is my night vision so bad?” Some relate difficulties when going from the bright outdoors into a dark theater, while others describe the harrowing experience of being “blinded” by a car’s oncoming headlights. Often the questions come at the end of an examination – when we are immersed in EHR documentation and trying to move on to our next patient. In short, they come at a time in which the easiest reply is a brief, well-rehearsed answer, often the same explanation we have given patients for years.
You see, it is easy to provide a patient with a reasonably technical account for their dark adaptation symptoms. You might start by explaining that humans lack the “rod predominant” retina of certain nocturnal animals, putting us at an anatomical disadvantage in suboptimal lighting. In the case of a contact lens or LASIK patient, you might attribute some of their symptoms to physiologic dilation beyond the optical/treatment zone. In certain age-appropriate patients, you can blame a good deal on media light scatter – be it cornea, lenticular or vitreous in nature. While each explanation likely satisfies the needs of your patient, are any, in fact, accurate? Sometimes I have the sense we should be spending a little less time on administrative activities and more time on better understanding the intricacies of conditions such as abnormal DA.
Granted, our ability to adapt to lighting changes and our capacity to function in dark environments naturally dwindles with age. However, when are patient symptoms merely physiologic and when are they a harbinger of disease? And in the case of abnormal DA, these diseases can include, among other things, age-related macular degeneration.
While we traditionally think of DA issues as being rod related and indicative of generalized retinal dystrophy or degeneration, the reality is that there is a growing body of literature linking this condition with a predisposition to AMD. It appears abnormal DA may well be a reliable early biomarker for AMD, one that sheds light on patient symptoms even in the presence of normal ophthalmoscopy.
The ramifications are huge, as we are constantly in search of a means by which to detect AMD before vision loss. Regarding DA as a biomarker, many questions remain. For whom is DA testing indicated? Is it a good surrogate for measuring therapeutic endeavors? Perhaps most importantly, will it provide (us and) our patients with a better explanation for their symptoms?
In this month’s issue, our feature article entitled, “Dark adaptation may detect AMD earlier than traditional technology” offers an in-depth look at the role DA testing is playing in primary eye care. I am sure you will find it a very worthwhile read – providing a better understanding of abnormal DA as well as serving as a good resource when answering patient questions.
On behalf of the Primary Care Optometry News team, thank you for your ongoing readership and best wishes for a happy, healthy and prosperous 2017!
- Reference:
- Phillips, D. EHR burden weighs heavily on physicians, leads to burnout. Medscape. www.medscape.com/viewarticle/868421. Posted Sept. 6, 2016. Accessed Dec. 28, 2016.