Evaluation of the effect of different disease-modifying drugs on the retina and optic nerve in patients with multiple sclerosis

Objective To compare the effects of first-line disease-modifying drugs on protecting the retina and optic nerve in relapsing remitting multiple sclerosis patients using optical coherence tomography, optical coherence tomography angiography, and contrast sensitivity (CS). Design Cross-sectional study. Participants A total of 60 eyes of relapsing remitting multiple sclerosis patients attending Ain Shams University Hospital from September 2022 to June 2024. Patients and methods Patients were divided into three groups: receiving dimethyl fumarate (DMF), interferon β 1A or interferon β 1B. Optic nerve and macula were assessed at baseline, 3, and 6 months by measuring the peripapillary retinal nerve fiber layer (pRNFL) thickness, ganglion cell complex (GCC) thickness, macular thickness, peripapillary vessel density (VD), superficial and deep capillary plexuses VD and foveal avascular zone area. CS testing was also done. Results CS demonstrated an increase in all groups but was greater in the DMF group. Macular thickness was increased in all groups. The pRNFL remained stable in all groups. However, GCC showed the most significant mean reduction in the interferon β 1A group. The mean macular and optic disc VD parameters were not significantly changed among groups. There was a more significant correlation between the superficial capillary plexus VD and GCC thickness with CS than with the other parameters. Conclusion Disease-modifying drugs showed significant preservation of the visual function and neuronal structure as noted by improved CS (highest in the DMF group) and macular thickness, and stable GCC and pRNFL thickness. The superficial capillary plexus VD and GCC thickness seem to be better disease biomarkers for monitoring visual function.