Evaluation of axonal optic nerve damage using visual evoked potentials and optical coherence tomography in patients with multiple sclerosis

Background and Objective: Axonal tissue impairment plays a substantial role in the development of disability in multiple sclerosis. The aim of our study was to analyze the clinical utility of visual evoked potentials (VEP) and optical coherence tomography (OCT) in the diagnosis of optic nerve axonal damage and to determine the correlation between the retinal nerve fiber layer at the temporal quadrant (RNFLT) thickness and the VEP amplitude in multiple sclerosis patients with and without a history of acute optic neuritis (ON). Material and Methods: This cross-sectional study included 69 relapsing-remitting patients with multiple sclerosis from Pauls Stradins Clinical University Hospital, who were divided into 2 groups: with and without a history of ON. The RNFLT thickness and the VEP amplitude were measured. Results: A total of 25 clinically affected eyes were studied. VEP showed a higher sensitivity (64%) than OCT (50%) in supporting a clinical diagnosis of ON. A significant correlation was found between the RNFLT thickness in the temporal segment and the average VEP amplitude both in the eyes of MS patients with (r_s=0.42, P=0.01) and without a history of ON (r_s=0.44, P<0.001). Conclusions: The evidence from this study suggests that diagnostics of optic nerve axonal damage is feasible by means of using the average VEP amplitude instead of OCT alone. However, the combination of VEP and OCT increases the chance to confirm the existence of ON. A significant correlation was found between structural and functional vision parameters for both patients with and without a history of ON.