Purpose
Early detection and treatment of age-related macular degeneration (AMD) improves patient outcomes. Dark adaptation (DA) impairment is a prominent visual function deficit in AMD, even among those with normal visual acuity. Traditional methods of measuring DA have been unsuitable for use in the clinic because of high patient burden and long test duration. To overcome these limitations, we developed the AdaptDx™ dark adaptometer as a screening tool for AMD. The AdaptDx™ provides an objective estimate and interpretation of DA. The test is 5 minutes, with low patient burden. This study evaluated the diagnostic sensitivity, specificity and reliability of the AdaptDx™.
Methods
A multicenter clinical study was conducted at Mass. Eye & Ear Infirmary, Johns Hopkins and Penn State. Two groups of subjects were enrolled: AMD and normal. Group assignment was based on fundus photograph grades. DA was measured using the AdaptDx™, which classified subjects as having normal DA or impaired DA based on a predetermined cut point. A subset of subjects had a second visit to evaluate reliability. Additional information collected included: BCVA, demographics and medical history. The study adhered to the principles of the Declaration of Helsinki and was HIPPA compliant.
Results
The sample consisted of 127 confirmed cases of early to advanced AMD, and 21 confirmed normals. The diagnostic test sensitivity was 90.6% (p <0.001). Thus the screening test correctly identified 115 of 127 AMD subjects. The diagnostic test specificity was 90.5% (p = 0.0271). Thus the screening test correctly identified 19 of 21 normals. Agreement between the first visit and second visit diagnosis was high at 94.7%.
Conclusions
The AdaptDx™ has a high diagnostic sensitivity, specificity and reliability for detection of AMD. Given its speed, ease of use, and accuracy, the AdaptDx™ has the potential to be the first practical tool for early detection of AMD in a clinical setting, similar to the use of visual field testing for screening of glaucoma.
Keywords: 412 age-related macular degeneration •
465 clinical (human) or epidemiologic studies: systems/equipment/techniques