Indocyanine green angiography of type 1 macular neovascularization in age-related macular degeneration and central serous chorioretinopathy reveals different disease mechanisms.

Abstract

To assess the rate of late phase hyperfluorescent plaque (LPHP) in type 1 macular neovascularization (MNV) in CSCR (central serous chorioretinopathy) and AMD (age-related macular degeneration) and to evaluate its prognostic value. Retrospective study including type 1 MNV in AMD and CSCR, from 2012 to 2020. Eyes with a late ICG-A image (>20mins) and clear visualization of MNV on OCTA were included. Quantitative and qualitative parameters on OCT and best corrected visual acuity were recorded at baseline, and after 3 monthly anti-VEGF injections. Eighty-three eyes were included, 35 with CSCR and 48 with AMD. Patients in the CSCR group were significantly younger than in the AMD group (61.3 ± 10.4 vs. 80.2 ± 6.8 years respectively, p<0.001), predominantly male (68.6% CSCR vs 35.4% AMD; p=0.003) and with a thicker choroid (379 ± 93.3 μm vs 204.2 ± 93.2 μm; p<0.001). Type 1 MNV in CSCR showed fewer LPHP compared to AMD (31.4% vs 77.1%; p<0.001). Baseline visual acuity was lower in patients with LPHP (0.37± 0.22 vs 0.27 ±0.28 LogMAR, p=0.03). On multivariate analysis, AMD was associated with the presence of LPHP (p<0.001). No significant difference in the response to anti-VEGF was observed. Leakage of macromolecules from MNV and accumulation in the RPE and/or in the stroma imaged by the LPHP is less common in eyes with type 1 MNV in CSCR than in AMD. Late phase ICG-A imaging offers an insight into the metabolism of the dye and the environment surrounding the neovascular membrane.