Multiple sclerosis (MS) is associated with altered binocular vision, with the most affected parameters being near distance and stereopsis, which becomes poorer in patients also suffering from optic neuritis (ON), according to study findings published in Clinical Optometry.
According to the research, no currently-available studies evaluate the impact of MS on binocular vision.
In total, 59 patients with MS (21 with monocular ON, 11 with binocular ON, and 27 without ON) and 26 age-matched healthy controls were included. The investigators analyzed binocular vision using near point of convergence (NPC), positive and negative fusional vergence for far and near distance, measurement of heterophoria at both distances with cover and modified Thorington tests, and random-dot stereoscopy.
The MS group had the highest abnormal NPC values, specifically in those with ON in 1 eye. Investigators discovered a trend towards more esophoric results in patients with MS, specifically in those with ON in one eye, for near vision.
No significant differences between the control and MS groups in positive fusional vergence was observed, although higher variability was noted in the MS groups. There were significant differences between the controls and MS groups in negative fusional vergence, with ON for both break-point and recovery points.
The analysis revealed that a high proportion of patients with MS had alterations on stereopsis, with the highest stereoscopic values found among patients with ON in both eyes (100%).
“Negative fusional vergence at near distance and stereopsis seem to be the binocular vision parameters affected most by MS, becoming worse in patients also suffering ON,” according to the researchers. “Although NPC and positive fusional vergence did not differ significantly between MS and healthy subjects, the variability of such parameters suggests a certain level of instability that should be investigated.”
Gil-Casas A, Pinero-Llorens DP, Molina-Martin A. Binocular Vision in Patients with Multiple Sclerosis.Clin Optom. Published online February 12, 2021. doi:10.2147/OPTO.S286862