Characteristics of Neovascularization in Early Stages of Proliferative Diabetic Retinopathy by Optical Coherence Tomography Angiography.

Purpose: To classify retinal neovascularization in untreated early stages of proliferative diabetic retinopathy (PDR) based on optical coherence tomography angiography (OCTA).

Design: A cross-sectional study.

Methods: Thirty-five eyes were included. They underwent color fundus photography, fluorescein angiography (FA), and OCTA examinations. Neovascularizations elsewhere (NVEs), neovascularizations at the disc (NVDs), and intraretinal microvascular abnormalities (IRMAs) were scanned by OCTA. The origin and morphology of NVE/NVD/IRMA on OCTA were evaluated. Retinal nonperfusion areas (NPAs) were measured using ImageJ software.

Results: In 35 eyes successfully imaged, 75 NVEs, 35 NVDs, and 12 IRMAs were captured. Three proposed subtypes of NVE were identified based on the origins and morphologic features. Type 1 (32 of 75, 42.67%) originated from the venous side, in a tree-like shape. Type 2 (30 of 75, 40.00%) originated from capillary networks, with an octopus-like appearance. Type 3 (13 of 75, 17.33%) originated from the IRMAs, having a sea fan shape. NVD originated from the retinal artery, from the retinal vein, or from the choroid, and arose from the bending vessels near the rim of the optic disc. IRMA originated from and drained into retinal venules, extending into the retina. The initial layer and affiliated NPA were significantly different in the 3 subtypes of NVEs (all P < .01).

Conclusions: OCTA allowed identification of the origins and morphologic patterns of neovascularization in PDR. The new classification of retinal neovascularization may be useful to better understand pathophysiological mechanisms and to guide efficient therapeutic strategies.