Observation of Retinal Neovascularization using Optical Coherence Tomography Angiography after Panretinal Photocoagulation for Proliferative Diabetic Retinopathy
Abstract Background: To describe the longitudinal changes of retinal neovascularization elsewhere (NVE) on optical coherence tomography angiography (OCTA) in proliferative diabetic retinopathy (PDR) treated by panretinal photocoagulation (PRP). Methods: Each patient included in this prospective clinical study was newly diagnosed PDR and NVE on both fundus fluorescein angiography (FFA) and OCTA. They received PRP of 4 sessions using multi-wavelength laser. Best-corrected visual acuity (BCVA) and OCTA images encompassing NVE were obtained before each PRP session and at 1 month, 3 months, and 6 months. Paired sample t-test was used to investigate differences between BCVA and NVE area before and after PRP. Results: Thirty-two eyes of 32 patients with a mean age of 50.56 ± 7.05 years were included. We found statistically significant reduction in the NVE size at all timepoints compared with the baseline except at 6 months (all P < 0.05). Further analysis demonstrated no statistically significant change of NVE size between two adjacent timepoints except from baseline to post-1st PRP and from 3 months to 6 months (both P < 0.05). BCVA at 3 months showed a statistically significant improvement compared with baseline (P < 0.05), but no significant changes of BCVA were observed during other visits.Conclusions: Using OCTA we found an overall regression in the NVE size following PRP starting as early as 1 week after 1st session and lasting until 3 months. OCTA provides quantitative information of vascular changes and could be a practical method for the longitudinal evaluation of neovascularization.