Optical coherence tomography and visual evoked potential and its relationship with neurological disability in patients with relapsing-remitting multiple sclerosis

Introduction: To evaluate the relationship between retinal nerve fiber layer involvement and visual evoked potential with the neurological disability scale in relapsing remitting multiple sclerosis. Methods: Fifty-two patients diagnosed with relapsing-remitting multiple sclerosis were evaluated for the study. Optical coherence tomography (retinal nerve fiber layer or RNFL and macular volume or MV), pattern visual evoked potential or VEP (latency and P100 wave amplitude), and neurological disability scale (EDSS) were performed. A baseline evaluation was carried out and it was repeated after one year and two years. Results: The baseline values in the retinal nerve fiber layer were 82.5 (75-93.5), the latency and amplitude of the VEP of 116 (108-125.5) and 9 (7-11), respectively, while the EDSS was 2 (1.5-3). A correlation was found between higher EDSS with prolonged latency and decreased amplitude of the P100 wave. There was an association between a higher EDSS with the prolongation of the latency of the P100 wave and a longer time of evolution of MS. No relationship was found between EDSS and macular volume. A higher EDSS was associated with a significant decrease in RNFL. When the discriminative performance of disability was evaluated, the latency of the VEP presented an area under the curve of 0.79 (CI95% 0.67- 0.92), the amplitude of the VEP an area under the curve of 0.71 (CI95% 0.56 - 0.87) and RNFL a area under the curve of 0.76 (95% CI 0.62 - 0.90. When comparing RNFL, MV and PEV in eyes without and with previous optic neuritis with RNFL values of 88 (81-97) and 76 (71-81) (p 0.0007), MV of 246 (232-261) and 241 (229-251) (p 0.2541), PEV latency of 109 (105-117) and 125 (118-129) (p 0.0001), VEP amplitude of 9 (7-10) and 9 (7-11) (p 0.9391), respectively, which shows a statistically significant correlation between decrease in RNFL and prolongation of VEP latency in eyes with previous optic neuritis. In the 2-year follow-up there were no significant differences between the values of RNFL, VEP and EDSS. Discussion: In our study, a relationship was evidenced between retinal nerve fiber thickness, PEV and the degree of disability measured by EDSS in patients with relapsing MS - remissions in their baseline values. A lower RNFL thickness was correlated with prolonged latency and decreased amplitude in the PEV and was associated with a higher EDSS. This relationship was more significant in eyes with previous optic neuritis in terms of decreased RNFL thickness and prolongation of PEV latency. No significant differences were found in the 2-year follow-up in the measurements made.