Color vision impairment in multiple sclerosis and neuromyelitis optica spectrum disorder

Abstract

Aim of the study: To evaluate the color vision impairment in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) and its relation to retinal neurovascular parameters measured by spectral-domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA). Material and methods: A total of 40 relapsing-remitting MS patients, 13 aquaporin-4 antibody-positive NMOSD patients, and 20 healthy controls were included. MS and NMOSD were divided into groups: eyes with a history of optic neuritis (MS+ON, NMOSD+ON) and eyes without previous ON (MS-ON, NMOSD-ON). Color vision was assessed with the Farnsworth-Munsell 100 hue test and results were presented as the square root of total error score (√TES) and total partial error score (√TPES) for the blue-yellow (B-Y) and red-green (R-G) axes. Ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) thickness was obtained with SD-OCT and vessel density of superficial, deep, and radial peripapillary capillary plexuses (SCP, DCP, RPC) was obtained with OCTA. Results: √TES, B-Y, and R-G √TPES were significantly higher in MS+ON, MS-ON, NMOSD+ON, and NMOSD-ON than in the control group. Color vision was comparable between MS+ON and MS-ON, whereas in NMOSD+ON, it was significantly more impaired than in NMOSD-ON and MS+ON. Within the groups, the severity of dyschromatopsia did not differ between the B-Y and R-G axes. √TES correlated with GCC thickness only in NMOSD-ON eyes, while in MS+ON, an association between √TES and vessel density of SCP and RPC was observed. Color vision did not correlate with RNFL thickness and vessel density of DCP in any group. Conclusions: Color vision defects were found in MS and NMOSD eyes, regardless of the history of ON. No specific predilection towards the blue-yellow or red-green axis was detected.