PURPOSE: To evaluate structural and angiographic neovascularization in patients with proliferative diabetic retinopathy (PDR) using volumetric three-dimensional optical coherence tomography angiography (OCTA).
METHODS: This prospective, observational cross-sectional study included 29 eyes of 27 patients with PDR. The angiogenic structure, feeding vessel (epicenter), flow volume, and flow volume density (FVD) of the neovasculatures were evaluated using three-dimensional OCTA imaging. The flow area and the flow area density (FAD) were also measured using en face OCTA imaging.
RESULTS: Sites of neovascularization were imaged successfully in 17 of the 29 eyes (58.6%). Three proposed types of neovascularization were identified on the basis of structural features seen on the three-dimensional OCTA images. Neovascularization of the adhesion type (9 of 17, 52.9%) adhered to the retinal vasculature. Those of the traction type (5 of 17, 29.4%) were partially separated from the retinal vascular plexus. Those of the mushroom type (3 of 17, 17.6%) were connected to the retinal vasculature via several epicenters. There was a significant difference between highly leaky (active) and faintly leaky (inactive) neovascularization for FVD, but not for flow area, flow volume, or FAD (P=0.01, 0.9, 0.6, and 0.1, respectively).
CONCLUSIONS: Volumetric three-dimensional OCTA revealed three types of neovascularization in PDR, and may be useful for assessing neovascular activity and planning vitrectomies.