Introduction: Multiple sclerosis is a common disabling progressive neurological disorder. Axonal loss is thought to be a likely cause of persistent disability after a multiple sclerosis relapse. Retinal nerve fiber layer (RNFL) imaging by optical coherence tomography (OCT) seems to be a non-invasive way of detecting optical axonal loss following optic neuritis.
Objective: To determine whether multiple sclerosis affects retinal nerve fiber layer measurements obtained with optical coherence tomography (OCT3-Carl Zeiss Meditec, Dublin, California, USA).
Material and methods: Diagnosis of MS was based on the MacDonald criteria. The cohort was divided into two groups based on their clinical course (multiple sclerosis with [n=8; 16 eyes] or without [n=7; 14 eyes] optic neuritis antecedents). The disease-free controls were matched for age and gender (n=15; 30 eyes). Retinal nerve fiber layer thickness was measured using optical coherence tomography (OCT; fastRNFL and RNFL thickness software protocol). Visual acuity, visual field, color vision were also noted.
Results: There were highly significant reductions (p<0.001) of retinal nerve fiber layer thickness in affected patients (with or without optic neuritis antecedents) compared with control eyes (fastRNFL and RNFL procedures). Visual acuity, visual field and color vision were globally less altered than OCT. There were no significant relationships among RNFL thickness and visual acuity, visual field, or color vision.
Conclusion: This study has demonstrated the anatomic changes of the retinal nerve fiber layer of patients with multiple sclerosis with optic neuritis antecedents. Thus axonal loss following optic neuritis can be detected with OCT. But the retinal nerve fiber layer of patients without optic neuritis is also thinner than disease-free controls so that chronic optic axonal loss can be frequent in multiple sclerosis. Additionally, OCT was more sensitive than the common ophthalmological explorations to detect optical nerve impairment during multiple sclerosis. Finally, we demonstrated that two procedures fastRNFL and RNFL could be used to detect optic nerve impairment.