Background and Objectives: The goal of this study was to evaluate the associations between peripapillary retinal nerve fibre layer (pRNFL) thickness, disability-related clinical measures, including the Expanded Disability Status Scale (EDSS), and report-based magnetic resonance imaging (MRI) findings in patients with multiple sclerosis (MS), and to explore potential longitudinal relationships between pRNFL changes and disability progression. Materials and Methods: A retrospective single-centre study was conducted in patients with MS diagnosed according to the 2010/2017 McDonald criteria at the Neurology Clinic of the Hospital of Lithuanian University of Health Sciences Kauno Klinikos. The study included 84 patients. pRNFL thickness was measured using optical coherence tomography (OCT) at baseline (defined as the time of diagnosis) and, for some patients, follow-up. Associations between pRNFL measures and clinical as well as MRI-derived variables were assessed using Spearman correlation and multivariable linear and ordinal regression analyses. Results: In cross-sectional analyses, lower baseline pRNFL thickness was associated with higher baseline disability (ρ = −0.257, p = 0.019) and greater worsening of EDSS over time (ρ = −0.268, p = 0.013). Significant associations were also observed between thinner pRNFL and pyramidal system impairment and bowel/bladder dysfunction. In adjusted linear regression models, each 20 µm reduction in pRNFL was associated with a 0.46-point increase in EDSS (B = −0.023, SE = 0.009) and a 0.32-point rise in cerebellar functional system score (B = −0.016, SE = 0.006). Among the 45 patients with repeat OCT, exploratory longitudinal pRNFL thinning showed directional trends toward increasing disability; however, these associations were not consistently significant after adjustment. Baseline pRNFL thickness showed a modest association with a composite MRI regional lesion score derived from report-based binary variables. Conclusions: In this real-world retrospective cohort, thinner pRNFL was associated with greater disability in cross-sectional analyses. Associations with individual MRI regions and radiological activity were limited and inconsistent. These findings should be interpreted as preliminary and hypothesis-generating. Further prospective studies are needed to clarify the potential role of OCT-derived pRNFL measurements.

Background and Objectives: Non-invasive biomarkers reflecting neurodegeneration are increasingly important in multiple sclerosis (MS). Optical coherence tomography (OCT) provides quantitative measures of retinal structure, most commonly peripapillary retinal nerve fiber layer (pRNFL) thickness. However, the potential clinical relevance of optic nerve head morphology, including cup-to-disc ratio (CDR), remains insufficiently explored. We investigated associations between OCT-derived parameters, subjective visual vertical (SVV), and disability in MS. Materials and Methods: In this retrospective study, 100 patients with MS were included. OCT parameters (pRNFL thickness and area-based CDR) were analyzed at baseline and follow-up. Clinical disability was assessed using the Expanded Disability Status Scale (EDSS). Detailed optic neuritis history was not consistently available in the retrospective clinical records and therefore could not be systematically accounted for in the analyses. SVV was evaluated in 37 patients using a virtual reality–based protocol. Associations were assessed using Spearman correlation and linear regression analyses. Multivariable regression models were adjusted for age, sex, and follow-up duration. Results: pRNFL thickness was not associated with baseline EDSS (rho = −0.06, p = 0.55) or annualized EDSS change. Baseline CDR correlated with both baseline EDSS (rho = 0.30, p = 0.0065) and follow-up EDSS (rho = 0.46, p < 0.0001). In univariable regression analysis, baseline CDR was associated with follow-up EDSS (B = 3.33, R² = 0.23, p < 0.0001), remaining significant after adjustment for age, sex, and follow-up duration (B = 2.59, 95% CI 1.26–3.92, p = 0.0002). No significant associations were observed between OCT parameters and SVV measures. Conclusions: Higher CDR values, but not pRNFL thickness, were associated with disability measures in this exploratory MS cohort. However, these findings should be interpreted cautiously because optic neuritis history could not be systematically accounted for and physiological optic disc variability may substantially influence CDR measurements.