Microperimetry of Nascent Geographic Atrophy in Age-Related Macular Degeneration

PURPOSE. To determine the microperimetric retinal sensitivity in areas with nascent geographic atrophy (nGA) compared with other pathological features in eyes with intermediate AMD. METHODS. Participants with bilateral intermediate AMD underwent microperimetry examinations and high-resolution spectral-domain optical coherence tomography (SD-OCT) scans in a prospective study. Twenty-two participants (24 eyes) identified as having a microperimetric stimulus sampling an atrophic area (nGA or drusen-associated atrophy detected on SD-OCT) in an eye were analyzed, using three neighboring nonatrophic regions (with or without AMD-associated features) in the same eye as reference areas. RESULTS. On average, the mean microperimetric retinal sensitivity was worse in areas with nGA than nonatrophic reference areas (P <= 0.008), but better than areas with drusen-associated atrophy (P = 0.008). Considering all the microperimetry points in an eye, there were only 6 out of 16 eyes (37.5%) where the retinal sensitivity over nGA was the worst performing point in the eye, while all eight out of eight eyes (100.0%) with an area of drusen-associated atrophy detected on SD-OCT had the worst-performing point over that area. CONCLUSIONS. Areas of nGA were characterized by worse microperimetric retinal sensitivity compared with nonatrophic areas in eyes with intermediate AMD, but better retinal sensitivity compared with areas of drusen-associated atrophy detected on SD-OCT. Areas of nGA were also not always the worst performing point in an eye. These findings further our understanding of the functional changes occurring in novel SD-OCT identified pathological changes in intermediate AMD.