Characteristics of Incident Geographic Atrophy in the Complications of Age-Related Macular Degeneration Prevention Trial

Objective To characterize the size, location, conformation, and features of incident geographic atrophy(GA) as detected by annual stereoscopic color photographs and fluorescein angiograms(FAs). Design Retrospective cohort study within a larger clinical trial. Participants Patients with bilateral large drusenin whom GA developed during the course of the Complications of Age-related Macular DegenerationPrevention Trial (CAPT). Methods Annual stereoscopic color photographs and FAs were reviewed from 114 CAPT patients in whom GA developed in the untreated eye during 5 to 6 years of follow-up. Geographic atrophywas defined according to the Revised GA Criteria for identifying early GA. 23 Color-optimized fundus photographs were viewed concurrently with the FAs during grading. Main Outcome Measures Size and distance from the fovea of individual GA lesions, number of areas of atrophy, and change in visual acuity (VA) when GA first developed in an eye. Results At presentation, the median total GA area was 0.26 mm 2 (0.1 disc area). Geographic atrophypresented as a single lesion in 89 (78%) eyes. The median distance from the fovea was 395 μm. Twenty percent of incident GA lesions were subfoveal and an additional 18% were within 250 μm of the fovealcenter. Development of GA was associated with a mean decrease of 7 letters from the baseline VA level compared with 1 letter among matched early age-related macular degenerationeyes without GA. Geographic atrophythat formed in areas previously occupied by drusenoid pigment epithelial detachments on average were larger (0.53 vs. 0.20 mm 2 ; P = 0.0001), were more central (50 vs. 500 μm from the center of the fovea; P P = 0.0003) than GA with other drusentypes as precursors. Conclusions Incident GA most often appears on color fundus photographs and FAs as a small, singular, parafoveal lesion, although a large minority of lesions are subfoveal or multifocal at initial detection. The characteristics of incident GA vary with precursor drusentypes. These data can facilitate design of future clinical trials of therapies for GA. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.