Relationship between choriocapillaris flow and scotopic microperimetry in early and intermediate age related macular degeneration

Purpose: To evaluate the correlation between choriocapillaris (CC) flow alterations and scotopic macular sensitivity (sMS) in patients with early and intermediate age-related macular degeneration (AMD). Design: prospective cross-sectional study METHODS: We acquired two 3x3mm and two 6x6mm swept-source optical coherence tomography angiography (OCTA) images of one eye of consecutive early or intermediate AMD patients at the Doheny UCLA Eye Centers. After 30 minutes of dark adaptation, the same eye underwent scotopic microperimetry with an 18°-wide grid (52 stimuli) centered on the fovea. The two en-face CC angiograms obtained from each scan pattern were compensated for signal loss and averaged. Main outcome measures: correlation between percentages of flow deficits (FD3mm and FD6mm) and sMS in the central 10° (MS10) and the overall pattern (MS18). Results: Thirty eyes of 30 patients were enrolled, with 14 (46.7%) having subretinal drusenoid deposits (SDD). In the averaged OCTA scans, the FD3mm was 12.56±2.41 % while the FD6mm was 9.33±1.84 %. The mean MS10 and MS18 were 13.84±5.89 dB and 14.64±5.21 dB, respectively. For the MS10, the multivariate regression analysis showed a significant association only with FD3mm (β:-0.628, p<0.001) while the MS18 was significantly correlated with both SDD (β:-0.32, p=0.047) and FD6mm (β:-0.473, p=0.005). Conclusions: Our study reports a significant correlation between the CC flow impairment and the sMS in eyes with early or intermediate AMD. If replicated in future longitudinal studies, the choriocapillaris FD may prove to be a useful parameter for evaluating the functional status and prognosis of these eyes.