Panretinal photocoagulation does not change macular perfusion in eyes with proliferative diabetic retinopathy

BACKGROUND AND OBJECTIVE: To quantify and compare the vessel density (VD) in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP), as well as the size of the foveal avascular zone (FAZ) in patients with proliferative diabetic retinopathy (PDR) before and after panretinal photocoagulation (PRP). PATIENTS AND METHODS: This prospective clinical study was conducted in the Department of Ophthalmology, Miulli Hospital Acquaviva delle Fonti, Italy. Each patient underwent measurement of best-corrected visual acuity (BCVA), fluorescein angiography, spectral-domain optical coherence tomography (OCT), and OCT angiography (OCTA) at baseline. Patients received PRP within 7 days from baseline, using frequency-doubled Nd:YAG pattern scan laser. BCVA and OCTA were repeated at 1 month and at 6 months. Repeated measure one-way analysis of variance was used to investigate differences between OCTA parameters before and after PRP. RESULTS: Eighteen eyes of 14 patients with diabetes (11 males, 78.6%) were enrolled. Patients underwent a mean of four laser treatments. BCVA was slightly worse at baseline (0.30 ± 0.20) compared to the visual function after 6 months (0.25 ± 0.24; P = .3). FAZ (0.33 ± 0.19 mm2 vs. 0.33 ± 0.16 mm2; P = .6), foveal SCP (16.4 ± 8.0 vs. 16.5 ± 6.5; P = .4), foveal DCP (28.5 ± 8.6 vs. 28.2 ± 8.1; P = .8), parafoveal SCP (38.4 ± 5.7 vs. 38.6 ± 4.5; P = .9), and parafoveal DCP (46.1 ± 5.2 vs. 43.8 ± 5.1; P = .3) did not change 6 months after PRP. CONCLUSIONS: OCTA parameters were not significantly affected by peripheral laser treatment at both short- (1-month) and medium- / long-term (6-month) follow-up. Further analysis with larger samples and longer duration is warranted to confirm these results.