Effect of pan retinal photocoagulation on Macular and optic nerve capillary density and foveal avascular zone area in patients with diabetic retinopathy An OCT angiography study

Abstract

Purpose: This study evaluated changes of macular and optic nerve capillary density, foveal avascular zone (FAZ) area and macular thickness following Panretinal photocoagulation (PRP) in eyes with severe non-proliferative diabetic retinopathy (NPDR) and early proliferative diabetic retinopathy (PDR) using optical coherence tomography angiography (OCTA).Patients and methods: The study enrolled 40 eyes of 28 subjects with severe NPDR and early PDR who were candidates for panretinal photocoagulation. The outcome measures were the difference in macular superficial and deep capillary plexus vessel densities, peripapillary capillary plexus (RPCP) vessel density, FAZ area, central macular thickness and best-corrected visual acuity at the baseline vs. at 1 and 3 months post-PRP.Results: The mean of macular VD at SCP and DCP showed a significant increase after PRP at 1- and 3-months. (All p < 0.05). The mean VD at RPCP decreased after PRP, this decrease wasn’t statically significant neither at 1 month nor at 3 months after PRP. (All p > 0.05). The superficial and deep FAZ area constricted 3 months post-PRP. (p < 0.05). Central macular thickness (CMT) showed statistically significant increase after laser treatment versus the baseline thickness, but no significant alterations in BCVA were reported post-PRP at 1- and 3-months. Conclusion: PRP supports the integrity of the macular and peripapillary microvasculature, the FAZ area constricted post-PRP, possibly because of the reflow of capillary plexus occlusion. After PRP, the CMT increased.