One common trio of multiple sclerosis symptoms is called Charcot's neurologic triad and it includes dysarthria, which is difficulty or unclear speech, nystagmus, which is involuntary rapid eye movements, and an intention tremor.
Nystagmus/nɪˈstæɡməs/ is a condition of involuntary (or voluntary, in rare cases) eye movement, acquired in infancy or later in life, that may result in reduced or limited vision. Due to the involuntary movement of the eye, it is often called "dancing eyes".