MS is a neurodegenerative disorder in the brain and spinal cord that affecting CNS through autoimmune mechanisms.Optic neuritis is one of the most common manifestations of MS resulting from the development of inflammatory demyelinating lesions of optic nerve.Retinal nerve fiber layer (RNFL) thinning indicating the axonal damages could be used as a biomarker to measure the severity of MS and ON disease.The present study aimed to determine the ability of OCT to detect changes in RNFLT and MV at presence of ON in MS patients.

In this analytical cross-sectional study, 120 patients (240 eyes) were included.The patients were examined by a neurologist and their data was recorded on a checklist and their MS type was determined by the physician.In this study, RNFLT and TMV were evaluated by age, gender, presence or absence of ON in the eyes, MS type, and primary manifestation of MS.

Out of the 120 MS patients studied, 24 patients (20%) were male and 96 patients (80%) were female. In general, out of the 240 eyes examined, 116 eyes had ON and 124 eyes did not have ON.There was no significant difference in RNFLT and TMV of male and female patients.The mean RNFLT was 76.25 μm in eyes with ON and 89.91 μm in eyes without ON.The mean TMV was 6.50 mm3 in the eyes with ON and 6.95 mm3 in the eyes without ON . RNFLT and TMV values were compared in different types of MS, none of which were significantly different.The findings showed an inverse relationship between EDSS disability score,duration of MS and visual acuity with RNFLT, which was statistically significant.

OCT provides us unique insight in structural changes in the anterior visual pathway, therefore it may complement our existing diagnostic tests and, as a potential outcome measure, help develop more effective therapeutic strategies for ON and MS patients.