Optical Coherence Tomography and Its Correlations With VEP in Multiple Sclerosis Patients

Vladimirova Z, Shmarov A and C

Abstract

Purpose: To demonstrate the results of morphological examination through optical coherence tomography (ОСТ) as a method for quantitative characterization of the impaired visual functions in patients with multiple sclerosis (MS) with acute optic neuritis (ON), ON in the past and without history for ON. Another purpose is to compare OCT findings to those from the visual evoked potentials (VEP) as a method for functional examination of visual functions to find the correlations between these methods. Materials: We have examined a total of 202 eyes - 31 eyes with acute ON, 50 eyes with ON more than 6 months ago and 121 eyes with no data for optic neuritis, of 101 patients with proved multiple sclerosis. 64.64% of the patients are female, and 37.36% are male. The mean age of the patients is 36.50 years (± 10.13). The results were compared to those of 94 eyes of 47 healthy volunteers. The mean age of the control subjects is 36.25 years (± 11.9), and the sex distribution is 57.45% females and 42.55% males. Methods: A comprehensive set of neuroophthalmological examinations was performed for all patients: determination of the best corrected visual acuity, assessment of the low contrast sensitivity (using the Pelli-Robson test), examination of the color vision with Ishihara tables, check of eye movements and fundus examination, visual evoked potentials (VEP) and visual field testing using automated perimetry. ОСТ examination was carried out in all patients (FD-OCT with a RTVue-100 unit; Optovue), using programs for thickness determination for the retinal nerve fiber layer (RNFL) and the macular ganglion cell complex (GCC). Results and conclusion: The performed ОСТ examinations demonstrated substantial thinning of RNFL (83.38 μm) and GCC (79.18 μm) in the eyes with ON in the past. The changes found in this group are more severe in comparison to the findings in patients with acute ON (mean thickness of 87.16 μm for RNFL and 86.08 μm for GCC). Most probably the reason for this fact is the time needed for the development of the reported atrophic changes. The patients who have never had ON were also found to have changes in the thickness of these layers, although less advanced (mean thickness of 99.13 μm for RNFL and 92.25 μm for GCC), which demonstrates the presence of asymptomatic loss of vision in MS patients. We also demonstrated statistically significant correlations between the morphological and functional methods (VEP) for examination of the visual functions.