Measurement Of Retinal Nerve Fibre Layer Thickness In Clinical Isolated Syndrome

Purpose:To evaluate the presence of abnormalities in the retinal nerve fibre layer (RNFL) thickness in patients with Clinical Isolated Syndrome (CIS) without optic neuritis and to correlate RNFL thickness with CIS stage according to Expanded Disability Status Scale (EDSS). Methods:Patients with CIS and disease-free controls were invited to enrol in the study. Patients with CIS were divided in two sub-groups according to EDSS: cognitively impaired (CI who scored below the fifth percentile of the controls performance on at least 2 cognitive tests) and cognitively preserved (CP who failed 0-1 test). RNFL thickness was evaluated in all groups by Stratus OCT (Carl Zeiss Meditec, Dublin, CA). Results:Fifty-two eyes with CIS and fifty-two disease-free eyes were included in the study. Cognitive impairment was found in 21 patients (39.5 %). The mean RNFL thickness measured by OCT in all groups was statistically different (ANOVA p<0.01). Compared with disease-free controls, CI sub-group showed a significant reduction in RNFL thickness (p<0.01, Tukey-Kramer test). Compared with disease-free controls, CP sub-group showed no significant difference in RNFL thickness (p= NS, Tukey-Kramer test). Compared with CP sub-group, CI sub-group showed a significant reduction in RNFL thickness (p<0.01, Tukey-Kramer test). Conclusions:Measuring RNFL with OCT could be useful to predict brain atrophy and cognitive impairment in CIS patients without optic neuritis.