Optical Coherence Tomography Angiography-Derived Peripapillary Vessel Density Findings in Multiple Sclerosis.

Background/Objectives: Multiple sclerosis (MS)-related optic neuritis (ON) results in thinning of the peripapillary nerve fiber layer (pRNFL) which tends to be temporal quadrant-predominant. Optical coherence tomography angiography (OCTA) enables visualization of the retinal vasculature. Prior studies have shown reduced peripapillary vessel density (VD) in MS but data on the quadrantic pattern of peripapillary VD loss are limited. Our objective was to investigate the pattern of OCTA-derived peripapillary VD reduction in MS. Methods: People with MS (PwMS) and healthy controls (HC) underwent optic disc OCTA scans (Solix, Optovue) and VD was derived for the peripapillary region and quadrants. Eyes with ON within six months were excluded. Analyses were performed with generalized estimating equations models and standardized coefficients are presented. Results: We included 50 eyes from 29 PwMS (12 ON, 38 non-ON) and 12 eyes from 6 HC. VD in the peripapillary region was lower in MS ON eyes compared to HC with the largest effect size observed in the temporal quadrant (average: -1.47, p < 0.001; superior: -1.08, p = 0.006; inferior: -0.94; p = 0.017; temporal: -1.55; p < 0.001; nasal: -1.06, p = 0.007). In MS non-ON eyes, only temporal VD was significantly lower compared to HC eyes (temporal: -0.77, p = 0.004). Moderate to strong correlations were observed between OCT and corresponding OCTA metrics from the same regions. Conclusions: Our findings suggest that vascular alterations in the peripapillary region may exhibit a temporal quadrant predominant pattern. Larger studies are needed to further characterize the patterns and temporal evolution of retinal peripapillary vascular injury in MS.