Comparison of Choriocapillary Flow Density Between Fellow eyes of Polypoidal Choroidal Vasculopathy and Neovascular Age-Related Macular Degeneration
Abstract Purpose: To compare the choriocapillary flow density (CFD) among the fellow eyes of polypoidal choroidal vasculopathy (PCV), neovascular age-related macular degeneration (nAMD) and healthy controls with spectral-domain optical coherence angiography tomography (SD-OCTA). Methods: This is a cross-sectional study, including the fellow eyes of 38 patients with unilateral PCV, 36 patients with unilateral nAMD, and 36 eyes from 36 healthy volunteers. PCV group was further classified into polypoidal CNV (P-CNV) and typical PCV (T-PCV) for subgroup analysis. Age, subfoveal choroidal thickness (SFCT), Age-Related Eye Disease Study (AREDS) classification and fellow eye diagnosis were acquired. All subjects underwent 6.0 mm scan pattern of SD-OCTA. Circles with radius of 1.00, 1.50 and 3.00 mm were manually selected in choriocapillaris (CC) slab, and CFD was calculated as the percentage of flow area to the whole selected area as CFD-1.00, 1.50, 3.00 respectively. Univariate and multivariate analysis were performed to study correlation between aforementioned factors with CFD, Results: Mean CFD-1.00, 1.50, 3.00 of nAMD group were 61.51, 63.18 and 66.20, significantly lower than PCV group (65.90, 66.89, 67.94, P<0.001 , <0.001, and 0.010, respectively) and control (66.28, 66.96, 68.42, P<0.001 , <0.001, and 0.001, respectively), while no difference were detected between PCV group and control or between PCV subtypes. AREDS classification and fellow eye diagnosis were correlated with CFD in univariate analysis, but only fellow eye diagnosis remained significantly correlated after multiple linear regression. Conclusions: CFD of nAMD fellow eyes were significantly lower than that of PCV and control eyes, while no difference was detected between PCV and control group, indicating different role of CC loss in early pathogenesis of nAMD and PCV.