Observation of retinal neovascularization using optical coherence tomography angiography after panretinal photocoagulation for proliferative diabetic retinopathy

BACKGROUND: To describe the longitudinal changes in retinal neovascularization elsewhere (NVE) as observed 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 with PDR and NVE confirmed by both fundus fluorescein angiography (FFA) and OCTA. They received four sessions of PRP using a multiwavelength laser. Best-corrected visual acuity (BCVA) and OCTA images of the NVE were obtained before each PRP session and at 1 month, 3 months, and 6 months after the PRP treatment. Generalized estimating equations (GEE) was used to investigate the differences between the BCVA and NVE areas 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 a statistically significant reduction in the NVE area at all time points compared with the baseline except at 6 months (all P < 0.05). Further analysis demonstrated no statistically significant change in the NVE area between two adjacent timepoints except from baseline to post-1st PRP (P < 0.05). BCVA at 3 months showed a statistically significant improvement compared with baseline (P < 0.05), but no significant changes in BCVA were observed during the other visits. CONCLUSIONS: We found an overall regression in the NVE area following PRP starting as early as 1 week after the 1st session and lasting up to 3 months. OCTA provides quantitative information on vascular changes and could be a practical method for the longitudinal evaluation of neovascularization.