OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF THE FOVEAL MICROVASCULATURE IN GEOGRAPHIC ATROPHY.

Abstract

To examine the retinal and choroidal foveal and parafoveal vasculature in patients with bilateral geographic atrophy (GA) secondary to age-related macular degeneration using optical coherence tomography angiography (OCTA). Fourteen eyes from 7 patients with and without fovea-sparing bilateral GA at St. Erik Eye Hospital. All patients were examined by optical coherence tomography angiography, en face OCT and fundus autofluorescence (FAF). Segmented optical coherence tomography angiography flow scans were obtained from the superficial retinal vascular layer (SL) and the choriocapillaris (CC) and correlated with areas of retinal pigment epithelial (RPE) loss on fundus autofluorescence. The foveal avascular zone (FAZ) was measured on superficial retinal vascular layer scans and compared to the GA area of each patient. No significant correlation (r = -0.17, P = 0.58) was found between superficial retinal vascular layer foveal avascular zone (0.49 mm ± 0.23 mm) and GA area (7.36 mm ± 4.36 mm). Absent or severely impaired CC flow was observed inside all GA lesions and to varied extent outside the GA margins including areas of fovea sparing. A high level of symmetry was observed in CC flow between fellow eyes. In this cross-sectional study, no relation was found between superficial retinal vascular layer foveal avascular zone and GA area. CC flow inside the GA was severely impaired, whereas CC flow outside the GA correlated poorly with both RPE integrity and visual acuity. Fellow eye symmetry suggests that CC monitoring may be a relevant clinical end point in interventional GA studies.