Quantitative Evaluation of Type 1 and Type 2 Choroidal Neovascularization Components Under Treatment With Projection-Resolved OCT Angiography

Purpose: To evaluate the response of type 1 and type 2 macular neovascularization (MNV) components under anti-vascular endothelial growth factor (VEGF) treatment in age-related macular degeneration (AMD) using projection-resolved optical coherence tomography angiography (PR-OCTA). Methods: This retrospective study included eyes with treatment-naïve exudative AMD treated with anti-VEGF injections under a pro re nata (PRN) protocol over 1 year. Two-dimensional MNV areas and three-dimensional MNV volumes were derived from macular PR-OCTA scans using an automated convolutional neural network. MNV was detected as flow signal within the outer retinal slab. Type 1 components and type 2 components were analyzed separately. Results: Of 17 enrolled eyes, 12 eyes were pure type 1 MNV and five eyes were type 2 MNV. In eyes with pure type 1, the total (sum of type 1 and type 2 components) MNV area and volume did not change from baseline to 6 months or 12 months (P > 0.05). In eyes with type 2 MNV, the total MNV area significantly decreased from the baseline to 6 months (P = 0.0074) and 12 months (P = 0.014). The total type 2 MNV volume also decreased from baseline visit to visits at 6 months and at 12 months, nearing statistical signifiicance (P = 0.061 and P = 0.074). In eyes with type 2 MNV, the type 1 component increased from 0.093 mm2 to 0.30 mm2 (P = 0.058), and the type 2 component decreased from 0.37 mm2 at 6 months to 0 at 12 months (P = 0.0087). Conclusions: Type 1 and type 2 MNV may have different response under PRN anti-VEGF treatment over 1 year.