Structural and Functional Retinal Changes in Multiple Sclerosis Patients in South West Nigeria: A Neuro-Ophthalmology Study

Multiple sclerosis (MS) is considered rare in sub-Saharan Africa but is increasingly diagnosed as neurological investigation capacity improves. Retinal OCT has emerged as a sensitive, non-invasive biomarker of axonal loss in MS, yet this application is entirely unexplored in Nigerian or broader West African MS patients. This study investigates structural and functional retinal changes in confirmed MS patients in South West Nigeria using spectral-domain OCT and electrophysiological assessment. A longitudinal case-control study with prospective enrolment over three years will be conducted at neurology clinics at Lagos University Teaching Hospital and Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife. Forty MS patients meeting the revised McDonald criteria and 80 age and sex-matched healthy controls will be enrolled. Spectral-domain OCT will measure peripapillary retinal nerve fibre layer thickness and ganglion cell inner plexiform layer thickness at baseline and 12-month follow-up. Visual evoked potentials will assess functional optic pathway integrity. Visual acuity, colour vision, and Humphrey visual field testing will document clinical visual function. Rates of RNFL thinning will be compared between groups and correlated with EDSS disability scores, number of relapses, and disease duration. MS has been studied extensively using retinal OCT biomarkers in European and North American cohorts, demonstrating RNFL thinning correlating with disability progression. Whether these biomarker relationships hold in the Nigerian MS phenotype, which may differ in relapse patterns and progression rates, is unknown. This study contributes foundational neuro-ophthalmology data to the West African MS literature. Recommendations will advocate for OCT integration into Nigerian MS management protocols. Keywords: multiple sclerosis, retinal OCT, neuro-ophthalmology, RNFL thinning, South West Nigeria