Nystagmus is a condition that causes the eyes to make quick, repetitive, uncontrolled movements — from side to side, up and down, or in a circular pattern — making the eyes appear to bounce around. The jerky motion may be triggered by optical stimuli or physical motion, or may occur at rest. Nystagmus can be mild, occurring only when a person looks to the side, or it may be severe enough to impair vision. Nystagmus often makes it difficult to focus steadily on a fixed object.
What causes nystagmus?
Nystagmus can be an inherited condition, showing up in early childhood, or it can develop later in life due to an accident or illness. Nystagmus is often a symptom of an underlying medical problem, such as stroke, multiple sclerosis, or head trauma. Other causes of nystagmus include severe nearsightedness, albinism, inflammation of the inner ear, central nervous system diseases, and medication side-effects. Sometimes the cause may be unknown.
In persons with multiple sclerosis, lesions in the brainstem and cerebellum may interfere with the nerve signals that affect motion of the eyes causing nystagmus. According to the MS Foundation, approximately 35 percent of individuals with multiple sclerosis may develop nystagmus. Abnormal gaze-holding mechanisms, vestibular imbalance, and impaired fixation are the most common causes of nystagmus in multiple sclerosis.
I’ve been one of those 35 percent as I developed mild nystagmus several years ago. Mine was triggered by visual stimuli such as looking up and down repeatedly between the piano keyboard and music while teaching. When nystagmus develops, it can be somewhat disorienting.
How is nystagmus treated in MS?
Treatment for nystagmus depends upon the type of abnormal eye movements involved.
- Pendular nystagmus may be treated with gabapentin or clonazepam.
- Uncontrolled trials have shown that downbeat nystagmus may be treated with clonazepam, baclofen, and gabapentin. Placebo-controlled studies have shown potassium channel blockers 3,4-diaminopyridine and 4-aminopyridine to be effective in reducing downbeat nystagmus.
- Upbeat nystagmus may also improve from treatment with oral baclofen (5-10 mg three times daily) or 10 mg of 4-aminopyridine used three times a day.
- Periodic alternating nystagmus (PAN) may respond to baclofen, phenothiazine, barbiturates, and memantine.
- Seesaw nystagmus and jerk hemi-seesaw nystagmus may respond to clonazepam or gabapentin.
While there is much overlap between effective treatments, it is interesting to note that different types of nystagmus respond to varying treatments. If nystagmus is a new symptom, it may signal a relapse. Call your neurologist to be evaluated and treated.
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Atkins EJ. Eye Movement Abnormalities in MS. Multiple Sclerosis Foundation. Accessed at http://www.msfocus.org/article-details.aspx?articleID=382
Costello F, Burton JM, Lee AG. Neuro-Ophthalmologic Manifestations of Multiple Sclerosis. Medscape online. Accessed at http://emedicine.medscape.com/article/1214270-overview#aw2aab6b5