Choriocapillaris flow impairment surrounding geographic atrophy correlates with disease progression

PURPOSE: To evaluate the correlation between the choriocapillaris (CC) flow alterations around geographic atrophy (GA) and the GA yearly growth rate (yGR) in patients with dry age-related macular degeneration (AMD). METHODS: We retrospectively reviewed and analyzed spectral domain optical coherence tomography (SD-OCT) and SD-OCT angiography images of consecutive patients with GA acquired using the Cirrus OCT at the Doheny Eye Centers between 2015 and 2017. All eligible patients had one 6 x 6 mm OCTA scan acquired during the first visit (considered as baseline) and two fovea-centered 512 x 128 macular cubes (6 x 6 mm) acquired at baseline and after a minimum of 12 months. MAIN OUTCOME MEASURES: The fundus images from the OCT volumes were used to manually delineate the GA area and calculate the yGR after square root transformation. The en-face angiogram at the level of the CC was analyzed for the percentage of flow voids (FV) outside the atrophic lesion (FV(OUT)) and in the para- and peri-atrophy regions (FV(500) and FV(1000) respectively; two concentric 500 μm wide rings around the atrophy edge). These values, together with the difference between FV(500) and FV(1000) (ΔFV), were then correlated with the corresponding yGR. RESULTS: Thirty-three eyes of 23 patients were eligible for the analysis. The mean yGR was 0.23 ± 0.17 mm/years. At baseline, the mean FV(OUT) was 41.86 ± 2.71%, while FV(500) and FV(1000) were 46.4 ± 4.17% and 42.51 ± 2.65% respectively. The mean ΔFV was 3.89 ± 2.6%. While in the univariable analysis, the yGR was significantly associated with FV(500) and with ΔFV (both p < 0.001), in multivariable model the association remained significant only with ΔFV (p < 0.001). CONCLUSIONS: Our study reports a correlation between the CC flow impairment around the atrophic lesions and their yGR in patients with GA. If replicated in future longitudinal studies, the choriocapillaris FV in the para-and peri-atrophy regions may prove to be useful parameters for evaluating the prognosis of these eyes.