Radial Peripapillary Capillary Vessel Density as a New Biomarker in Pseudophakic Cystoid Macular Edema

<b>Background/Objectives:</b> Our aim was to investigate the vessel density (VD) of the radial peripapillary capillary (RPC) plexus in eyes with early pseudophakic cystoid macular edema (PCME) and controls using OCT angiography (OCTA). <b>Methods</b>: Patients with PCME and controls underwent structural OCT to assess the retinal nerve fiber layer (RNFL) and central macular thickness (CMT) and 6 × 6 mm² macular OCTA to record the superficial (SVP), deep (DVP) vascular plexus, and choriocapillaris. A scan area of 4.5 × 4.5 mm² was centered on the optic disk to analyze the RPC plexus VD. Fluorescein angiography was performed in PCME patients. <b>Results</b>: Data from 30 PCME and 30 control eyes, matched for age, were analyzed. The mean CMT was larger in PCME eyes than in control eyes (450 ± 6.5; 243 ± 3.5 micron, <i>p</i> < 0.001). The mean RNFL thickness was significantly greater in terms of global thickness in the PCME group compared to the control group (103 ± 5.2; 91 ± 2.5 micron, <i>p</i> < 0.001). The PCME group had a statistically significant increase in the VD of the RPC in the whole image, peripapillary region, and inside disk compared to the control group (<i>p</i> < 0.001). There was no difference in SVP (<i>p</i> = 0.660) or DVP (<i>p</i> = 0.480) VD between the two groups. A significant correlation was found between the average RNFL thickness and the VD of the RPC (<i>p</i> < 0.05). <b>Conclusions</b>: Eyes with PCME showed increased VD of the RPC and a correlation between this parameter and RNFL thickness; the VD of the RPC shows potential as a reliable non-invasive biomarker for the early diagnosis of PCME.