Nystagmus is a common symptom of multiple sclerosis (MS). It can happen only when people look to the side or it can be severe and constant enough to impair vision.
In people with MS, nystagmus is often associated with a loss of coordination between the eyes, caused by a lesion in the part of the brain called the medial longitudinal fasciculus. It can also be due to a lesion in the cerebellum or the brainstem.
There are no effective symptomatic treatments for nystagmus, although corticosteroids are sometimes given to reduce the severity or duration of this symptom.