Geographic Atrophy and OCT Angiography: Descriptive Study and Correlation With Autofluorescence.

Abstract

Geographic atrophy (GA) involves the progressive loss of retinal pigment epithelium (RPE), photoreceptors, and choriocapillaris (CC). CC flow within a GA area is severely impaired in patients with atrophic age-related macular degeneration. The aim of this study was to compare GA area measured on optical coherence tomography angiography (OCTA) (CC nonperfusion area) and on fundus autofluorescence (FAF). In this prospective, observational, cross-sectional study, OCTA and FAF were performed in patients with GA. On OCTA (CC segmentation), the CC nonperfusion area was measured manually using calipers. On FAF, GA was manually delimited, and the total surface was obtained using Region Finder software. The primary endpoint was to compare the CC nonperfusion area measured on OCTA and on the gold standard method (FAF). Forty eyes of 34 patients with a mean age of 82.63 years ± 9.21 years (range: 66 years to 100 years) were included. The mean GA area measured on FAF and OCTA was, respectively, 2.184 ± 3.045 mm2 and 2.349 ± 3.237 mm2 (P = .035). The mean difference was 0.165 ± 0.290 mm2. A strong correlation was found between both measurements (r = 0.97; P < .0001; confidence interval: 0.98-0.99), although the CC nonperfusion area was larger than the GA area on FAF (P = .035). In this study, the authors showed that in GA, the CC nonperfusion area correlates linearly with the GA area assessed by FAF. Also, the CC nonperfusion area is larger than the GA area measured by FAF, suggesting that CC degeneration could occur before RPE degeneration in GA. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e222-e228.].