Nystagmus (pronounced ni-STAG – mus) is an involuntary, rhythmic movement of the eyes.
It usually involves slow and fast movements from side to side. Vertical (up and down) nystagmus is far less common than horizontal (side to side) nystagmus. It can either be congenital (present since birth) or it can develop later in life.
Since the eye movement is involuntary, nystagmus can significantly affect vision. Depth perception (the ability to know when things are close or far away) is reduced, causing proneness to tripping or clumsiness. Some people may experience vertigo — the sensation of spinning. These problems make it difficult to perform everyday activities such as driving a car, reading or walking up and down stairs. Some people with the condition may even lose part or most of their vision.
What causes nystagmus?
There are many different causes of nystagmus, including:
- poor development of eye control early in life (this may be due to an early eye disease or visual problem);
- inheritance of the disorder from a family member;
- Down syndrome;
- lesions in the brain;
- head trauma or accident involving the body’s motor system;
- eye disease or disorders, such as optic nerve degeneration, severe astigmatism (uneven curvature of the cornea) or high myopia (nearsightedness);
- disease or illness of the body, such as multiple sclerosis, stroke or severe inflammation of the ear;
- certain medications, such as lithium or antiseizure medication;
- alcohol or drug use;
- albinism (lack of skin pigmentation).
In some cases, nystagmus may occur for no known reason. The intensity of the eye movement may also be affected by emotional and physical factors such as stress, fatigue or anxiety.
Your ophthalmologist (Eye M.D.) and/or neuro logist may use different tests or examinations to assess the cause, type and severity of your nystagmus.
What tests will be performed?
In order to gather more information about your condition, your ophthalmologist or neurologist may perform some of the following tests and examinations:
- computerized tomography (CT) scans (x – rays of the brain);
- magnetic resonance imaging (MRI), which uses magnetic and radio waves to produce images of the brain;
- examination of the interior of the eye with an instrument called an ophthalmoscope;
- directional testing, in which the doctor will ask you to look or move your head in certain directions;
- visual acuity testing.
How is nystagmus treated?
Sometimes treating the source of nystagmus can relieve the condition (for example, ceasing medication, drug or alcohol use). In most cases, however, symptoms of nystagmus can be reduced with treatment, but not cured.
Types of treatment include:
- prisms, eyeglasses or contacts to help to relieve the effects of nystagmus;
- surgery to alter the eye muscles causing the involuntary movement;
- Botox (botulinum toxic) injections to relax the eye muscles;
- adopting an angle of vision to see better (for example, sitting off to the side of a television).
In many cases, using low-vision techniques and aids will increase your level of vision. This may include using large print materials, bright lighting, high contrast materials and magnifying devices.
Your ophthalmologist will recommend the best treatment option to help you make the most of your vision. Because of the conditions associated with nystagmus (eg, head trauma, multiple sclerosis, effects of certain medications), follow-up with your primary care physician or referral to a specialist is usually recommended as part of treatment. Your ophthalmologist and other doctors may work together to treat your condition.
