Effects of Panretinal Laser Photocoagulation on the Macular Vascular Structure in Proliferative Diabetic Retinopathy Without Macular Edema: A Prospective Optical Coherence Tomography Angiography Study

Abstract Purpose: This research seeks to assess the changes in macular vascular metrics after panretinal photocoagulation (PRP) in eyes with proliferative diabetic retinopathy (PDR) absent of diabetic macular edema utilizing optical coherence tomography angiography (OCTA). Methods: In total, 25 eyes were evaluated prospectively. All patients underwent ophthalmic evaluations prior to PRP and at the 3- and 6-month follow-ups. Central macular thickness (CMT) was assessed with spectral-domain optical coherence tomography. OCTA was utilized to evaluate vascular density (VD) in the superficial and deep foveal avascular zone (FAZ), superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina (OR), and choriocapillaris (CC). VD was examined in foveal and parafoveal regions throughout the superior, inferior, nasal, and temporal quadrants. Results: The study sample included 36.8% males and 63.2% females, with an average age of 53.26 ± 13.64 years. The baseline best-corrected visual acuity (BCVA) was 0.1 ± 0.09 logMAR, while the mean baseline CMT was 264.6 ± 27.28 µm. While BCVA remained stable (p > 0.05), CMT significantly increased at 3 and 6 months post-PRP to 284.24 ± 32.07 µm and 290.16 ± 32.93 µm, respectively (p < 0.001). No significant VD changes were observed in SCP, DCP, CC, or FAZ, while OR VD significantly decreased in the nasal and temporal parafoveal regions at 6 months (p = 0.024 and p = 0.014). CMT showed a moderate negative correlation with the superficial FAZ area. Conclusion: OCTA evaluation revealed no clinically significant macular vascular changes following PRP in treatment-naive PDR eyes without macular edema.