Longitudinal assessment of type 3 macular neovascularization using 3D volume-rendering OCTA

Objective: To investigate the evolution of treatment- naive type 3 macular neovascularization (MNV) undergoing anti-vascular endothelial growth factor (VEGF) treatment through volume rendered three-dimensional (3D) optical coherence tomography angiography (OCTA). Design: Retrospective observational study. Participants: Patients with type 3 MNV and age-related macular degeneration (AMD). Methods: Included subjects had three loading injections of an anti-VEGF agent. The OCTA volume data at baseline and follow-up were processed with a previously published algorithm in order to obtain a volume-rendered representation of type 3 MNV. Progressive changes in type 3 lesions were analyzed via 3D OCTA volume rendering. Results: A total of 14 treatment-naive eyes with type 3 MNV from 11 AMD patients (7 females) were included. At both baseline and follow-up visits, a type 3 MNV complex was identifiable. Each complex was composed of a mean number of 2.5 +/- 0.7 vascular branches at baseline and 1.4 +/- 0.6 at the follow-up visit (p < 0.0001). The mean changes in central macular thickness and visual acuity were significantly correlated with modifications in the number of type 3 MNV branches (rho = -0.533, p = 0.049, and rho = -0.581, and p = 0.040, respectively). Conclusions: This study demonstrated that type 3 lesions do not disappear completely after loading treatment, as indicated previously by histopathologic studies. Importantly, quantitative volume changes in type 3 lesions are directly associated with treatment response.