Nystagmus is the involuntary movement of the eyes, causing them to flick rapidly from side to side, up and down, or in a rotary manner. It can be a visual symptom of multiple sclerosis, although nystagmus is also found as a congenital condition in some children, or can be brought on by viral infection, poor nutrition or recreational drug use.
Nystagmus in MS may be caused by nerve damage to the cerebellum or brainstem, regions of the brain which co-ordinate balance, muscle movements and vision. Alternatively, nystagmus may arise from damage to the optic nerve.
Mild nystagmus sometimes goes unnoticed by the person affected, but can be clearly seen by an observer looking at their eyes. If it is more persistent, nystagmus may contribute to dizziness or nausea, and also vision problems, as the person affected is unable to hold a steady gaze. Combined with balance issues, nystagmus can contribute to falls.
Sometimes, a person with nystagmus develops a head nod or shake which can partially offset the effect of the flicking eyes and help them concentrate. In some head positions, the eye movements cease or reduce. A person with nystagmus might therefore hold their head in an awkward or unusual way, which can result in stiffness or pain in the neck and shoulders.
Nystagmus can be a difficult symptom to treat, but here are some options:
- Wearing glasses or contact lenses can slow down the eye movements but will not correct nystagmus entirely.
- Drug therapy with gabapentin or memantine may reduce the amount that the eye twitches.
- Very occasionally, surgery might be performed, but this would be to adjust the head position in which an affected person can see best, not to correct the nystagmus itself.
- One study describes a person with MS who discovered that vibration from a handheld massager applied to her skull successfully damped her nystagmus and temporarily improved her vision.