Thickness of retinal nerve fiber layer correlates with disease duration in parallel with corticospinal tract dysfunction in untreated multiple sclerosis

Optical coherence tomography (OCT) is an emerging clinical and research measure of retinal nerve fiber layer (RNFL) loss in multiple sclerosis (MS) and may reflect neurodegeneration. Few studies capture the effect of disease duration on the RNFL in subjects without exposure to disease-modulating therapies. We assessed the relationship of RNFL loss with disease duration in subjects with untreated MS and determined if such loss paralleled corticospinal tract dysfunction in MS. Subjects underwent OCT (n = 52) and visual testing (n = 60). Either they were either examined or they participated in a validated telephone interview so we could determine their Expanded Disability Status Scale (EDSS) scores. Both RNFL thickness (Spearman r_s = -0.47, p < 0.001) and EDSS scores (r_s = 0.51, p < 0.001) correlated with disease duration. RNFL thickness correlated with EDSS scores (r_s = -0.43, p < 0.001). In conclusion, RNFL loss correlates with disease duration and EDSS scores in subjects with untreated MS, indicating that OCT may capture neurodegeneration.