AIM: To investigate the changes of retinal vascular parameters and retinal layer thickness in patients with multiple sclerosis(MS).METHODS: This single-centered case-control study was performed on a MS group of 42 patients diagnosed with MS and a control group of 43 healthy hospital staff matched in terms of age and sex at Iran University, department of neurology and ophthalmology from March 2020 to March 2021. The ophthalmic parameters of each patient were recorded, and optical coherence tomography was used to evaluate the retinal thickness in the layers.RESULTS: This study enrolled a total of 85 participants, with a mean age of 40.44±11.52 years, including 61 females(72%). The control group consisted of 43 individuals with a mean age of 39.49±11.07 years, while the MS group comprised 42 participants with a mean age of 41.40±12.01 years. The mean disease duration in the MS group was 8.45±6.04 a. The thickness of the ganglion cell layer in the right eye was significantly lower in the MS group compared to the control group(P=0.034). In addition, except for the left nasal sector(P=0.106), the mean peripapillary neurofibrillation in all examined sectors were significantly lower in the MS group than in the control group(P<0.05). The average vessel density in both the deep and superficial capillary plexuses across all regions of both eyes was lower in the MS group than in the control group, with all comparisons for the superficial capillary plexus showing statistical significance(P<0.05 for all except the left nasal sector).CONCLUSION: The thickness of the retina of patients with MS is significantly reduced. Therefore, optical coherence tomography results can be used as a reliable tool to evaluate disease progression and prognosis in MS patients.