[Atrophy of the retinal nerve fibre layer in multiple sclerosis patients. Prospective study with two years follow-up].

OBJECTIVE To evaluate the changes over two years in the retinal nerve fibre layer (RNFL) of patients with multiple sclerosis (MS). To compare the ability of optical coherence tomography (OCT), scanning laser polarimetry (GDx), visual evoked potentials (VEP) and visual field examination to detect axonal loss in these patients. MATERIAL AND METHODS Fifty eyes of MS patients without episodes or optic neuritis during follow-up were enrolled in this study. All patients underwent a complete ophthalmic examination that included visual acuity (VA), colour vision, refractive evaluation, visual field examination, OCT, GDx and VEP. All the patients were re-evaluated over a period of 12 and 24 months. Correlations between parameters were analysed by Pearson's test. RESULTS There were changes in the RNFL thickness in MS patients with a 12 and 24-month follow-up. Differences between baseline and 2-year evaluation were statistically significant (p ≤ 0.05, t test) in the mean, superior and inferior RNFL thickness and macular volume provided by OCT, while no significant differences were found using functional parameters (VA, colour vision, visual field and VEP) and GDx. The greater differences were obtained in the inferior RNFL thickness (113.67 frente a 105.39 μm, p < 0.001). Correlations were observed between structural parameters using GDx and TCO. CONCLUSIONS Progressive axonal loss can be detected in the optic nerve of MS patients. Measurements provided by TCO are useful tools to evaluate structural abnormalities in the RNFL and changes in macular volume, however these changes were not detected using functional tests or GDx.