Optical Coherence Tomography Angiography Changes in Macular Area in Patients with Proliferative Diabetic Retinopathy Treated with Panretinal Photocoagulation.

Background: The purpose of this study was to investigate the changes in macular microvasculature using optical coherence tomography angiography (OCTA) in association with functional changes in patients with proliferative diabetic retinopathy (PDR) treated with panretinal photocoagulation (PRP) with a follow up of 12 months.

Methods: The participants in this study were 28 patients with PDR and no macular oedema, who were eligible for PRP. All participants underwent best-corrected visual acuity (BCVA) measurement, optical coherence tomography (OCT), and OCT angiography (OCTA) at baseline (before treatment) and at months 1, 6, and 12 after the completion of PRP treatment. The comparison of OCTA parameters and BCVA between baseline and months 1, 6, and 12 after PRP was performed.

Results: There was a statistically significant decrease in foveal avascular zone (FAZ) area at months 6 and 12 of the follow-up period compared to baseline ( = 0.014 and = 0.011 for month 6 and 12, respectively). Of note is that FAZ became significantly more circular 6 months after PRP ( = 0.009), and remained so at month 12 ( = 0.015). There was a significant increase in the mean foveal and parafoveal vessel density (VD) at all quadrants at the superficial capillary plexus (SCP) at month 6 and month 12 after PRP compared to baseline. No difference was noticed in VD at the deep capillary plexus (DCP) at any time-point of the follow up. BCVA remained the same throughout the follow-up period.

Conclusions: At months 6 and 12 after PRP, foveal and parafoveal VD at SCP significantly increased compared to baseline, while the FAZ area significantly decreased and FAZ became more circular.