OCT Angiography of Type 1 Macular Neovascularization in AMD: A Morphometric Evaluation

Purpose: To determine biomarkers of macular neovascularization (MNV) in neovascular age-related macular degeneration through the application of an automatic algorithm based optical coherence tomography angiography (OCTA) analysis. Methods: In this retrospective, observational, single-center, cross-sectional study, patients with a diagnosis of age-related macular degeneration complicated by type 1 MNV were included. MNV was detected with OCTA and scans were analyzed with a qualitative and quantitative open-source image processing package. For each analyzed image, we automatically acquired the following data: Total MNV area, vessel area, vessel density (VD), total number of branches, total number of vascular junctions, mean vessel length, mean vessel diameter, fractal dimension (FD), junction density, and vessel tortuosity. Results: The following morphological parameters revealed a significant negative correlation with best-corrected visual acuity: MNV area - Spearman ρ = -0.309 (P = 0.002); vessel area - Spearman ρ = -0.315 (P = 0.002); total number of vascular junctions - Spearman ρ = -0.285 (P = 0.005), and VL - Spearman ρ = -0.304 (P = 0.003). Immature MNV lesions were significantly associated with better vessel area than mature and hypermature lesions. Conclusions: Several automated MNV-associated morphological parameters can correlate with the best-corrected visual acuity. Further studies are warranted to determine if these OCTA biomarkers can be applied to guide anti-vascular endothelial growth factor therapy and predict response to treatment.