The Relationship Between OCT and VEP Parameters with Disability and Disease Duration in Relapsing–Remitting Multiple Sclerosis

<b>Background:</b> Optic neuritis (ON) is a common manifestation of multiple sclerosis (MS), serving as a clinical window into central nervous system demyelination. Optical coherence tomography (OCT) and visual evoked potentials (VEPs) are complementary non-invasive tools for assessing structural and functional damage to the visual pathway. The objective of this paper is to evaluate correlations between OCT and VEP parameters in MS patients with and without a history of ON and assess their relationship with disease duration and disability (EDSS). <b>Methods:</b> This cross-sectional study included 54 eyes from 27 relapsing-remitting MS patients. OCT was used to measure circumpapillary and the temporal peripapillary retinal nerve fiber layer (pRNFL) and the foveal/parafoveal ganglion cell-inner plexiform layer (GCIPL) thickness. VEPs assessed P100 latency and amplitude. Patients were grouped by ON history. <b>Results:</b> Eyes without ON showed a significantly greater circumpapillary pRNFL thickness (mean difference: 18.27 ± 5.33 µm, <i>p</i> = 0.001), temporal pRNFL thickness (15.71 ± 5.49 µm, <i>p</i> = 0.006), and parafoveal GCIPL thickness (12.85 ± 5.3 µm, <i>p</i> = 0.019) compared to ON eyes. p100 latency was shorter and the amplitude was higher in NON eyes, but without statistical significance. Strong negative correlations were found between OCT thickness and EDSS and disease duration. p100 latency correlated negatively with OCT parameters, while amplitude showed a positive correlation with pRNFL thickness in ON eyes. <b>Conclusions:</b> OCT parameters, particularly pRNFL and GCIPL thickness, correlate with functional and clinical markers of MS. Combined OCT-VEP evaluation enhances the assessment of neurodegeneration and disease progression.