One’s ability to adapt to different lighting situations is affected in those who have macular degeneration (AMD) making it more difficult to adjust to new lighting environments.  Diminished light adaptation in changing light levels when transitioning for example from outside to inside is slower and a common symptom in those with this retinal condition. But it’s the ability to adapt to darkness and the time it takes for one’s vision to recover when going from light to darkness that is most affected.

Contributing Factors

The photoreceptor cells that handle our night vision die and degenerate sooner than the photoreceptor cells that manage our daytime vision.  When layers of the retina, like the Retinal Pigment Epithelium (RPE) and Bruch’s Membrane, start to breakdown, oxygen and nutrients are prevented from reaching the rods and cones. The demand for nutrients and oxygen is especially high during dark adaptation as is the ability to transport out the by-products from this process.  For someone with macular degeneration it will take their eyes longer to adjust when walking into a dark movie theater or dark restaurant.

Dark Adaptation Can Be Tested

The time it takes to adjust to darkness or for vision to recover when walking into a dark environment can be measured and tested.  The test is non-invasive and can be done at an eye doctor’s office and incorporated into a general eye exam.  In fact, testing for dark adaptation was shown to be more sensitive to AMD that other visual function tests such as photostress, contrast sensitivity and visual acuity.  The device and name of the test is called AdaptDX.

In the study, “Comparison of Visual Function Biomarkers in Individuals with Early or Intermediate AMD” at Penn State College of Medicine they found “potential of the AdaptDX as a rapid diagnostic for AMD. It showed the ability to discriminate AMD patients from normal adults in the study population using a test lasting  ≤ 20 minutes with a sensitivity of 91% and a specificity of 100%. ”   Changes in the ability to adapt to darkness can be observed and measured before structural changes to the retina can be seen. The testing can also be used to monitor the effectiveness of therapies to treat macular degeneration.

Justin Bazan, OD explains the benefit of this type of testing, “AdaptDx will allow us to present to our patients evidence of functional loss, which will help them realize the importance of acting upon our prescribed therapies and lifestyle changes. Most importantly, it will help us to accomplish this earlier on in the disease process.”

Find out how to get this test and who should be tested by watching this short video:

AdaptDX – Testing for Adaptation to Darkness

Leslie Degner, RN, BSN

www.WebRN-MacularDegeneration.com