Volume-Rendered Projection-Resolved OCT Angiography: 3D Lesion Complexity Is Associated With Therapy Response in Wet Age-Related Macular Degeneration

Purpose: To explore whether quantitative three-dimensional (3D) analysis of choroidal neovascularization (CNV) using projection-resolved optical coherence tomography angiography (PR-OCTA) is associated with treatment response in neovascular age-related macular degeneration (nAMD). Methods: Retrospective, cross-sectional study of 51 eyes of 49 patients undergoing individualized anti-VEGF therapy for nAMD. Patients were classified as "good" or "poor" responders, requiring injections at less or more frequently than 6-week intervals, respectively. Cross-sectional PR-OCTA images were used to measure the distance between Bruch's membrane and highest CNV flow signal. The number of flow layers within the CNV and the distance between these flow layers (CNV flow thickness) were also analyzed. Two masked, independent graders measured the PR-OCTA parameters. We used 3D volume-rendered PR-OCTA to confirm the number of CNV flow layers and further evaluate CNV complexity. Results: Poor responders had significantly greater distance between Bruch's membrane and highest CNV flow signal (P < 0.01), greater number of CNV flow layers (P = 0.022), and greater CNV flow thickness (P < 0.01). Volume-rendered PR-OCTA images confirmed the number of CNV flow layers. Conclusions: Cross-sectional and 3D volume-rendered PR-OCTA provides a novel approach for quantifying CNV complexity. Our results suggest that CNV acquiring more complex 3D vascular structure are associated with more frequent long-term anti-VEGF therapy, reflecting a particular pattern of normalization or complex CNV remodeling process that characterizes these less responsive eyes.