Characteristics of Retinal Neovascularization in Proliferative Diabetic Retinopathy Imaged by Optical Coherence Tomography Angiography. 
To characterize the morphology of neovascularization at the disc (NVD) and neovascularization elsewhere (NVE) in treatment-naïve or previously treated proliferative diabetic retinopathy (PDR) patients using optical coherence tomography (OCT) angiography.  En face OCT angiograms of NVD/NVE in 40 eyes of 33 patients with PDR were acquired using RTVue XR Avanti OCT.  The morphology of NVD/NVE on OCT angiograms was evaluated, and the activity was determined by biomicroscopy and fluorescein angiography (FA).  In 12 eyes that were treated or treatment-naïve, changes in the morphology and vessel area of NVD/NVE before and after panretinal photocoagulation (PRP) were investigated.  Twenty eyes had treatment-naïve PDR, whereas 20 eyes were previously treated with PRP.  All treatment-naïve NVD/NVE had remarkable (i.e., active) leakage in early-phase FA.  Ninety-five percent of treatment-naïve NVD/NVE observed by OCT angiography had exuberant vascular proliferation (EVP), identified as irregular proliferation of fine (smaller-caliber) new vessels; whereas, the presence of EVP in previously treated eyes (13/20) was significantly less than in treatment-naïve eyes (65% vs. 95%, P = 0.043).  The remaining seven treated eyes had pruned NVD/NVE without EVP, observed as fibrotic changes or faint (inactive) leakage in FA.  The vessel areas of NVD/NVE significantly decreased following PRP (n = 12, P = 0.019), and NVD/NVE morphology showed pruning and decreased EVP.  Exuberant vascular proliferation on OCT angiograms should be considered as an active sign of neovascularization; therefore, morphologic evaluation of neovascularization using OCT angiography may be useful to estimate the activity of each neovascularization in eyes with PDR.