Definition

Nystagmus is a type of involuntary movement of the eyes. It is usually side-to-side, but sometimes is up and down or in a circular fashion (rotatory nystagmus). The movement varies between slow and fast and usually involves both eyes. Nystagmus most often occurs in infancy, but it can also be acquired later in life. In infancy, it tends to develop between six weeks and three months of age.

Nystagmus can reduce vision and can also be associated with other conditions that limit vision, such as strabismus]]> (an eye turned in, out, up, or down). Nystagmus affects people in many different ways. It is important to see a doctor so that treatment for the condition and any associated disorders can be obtained to improve vision. Sometimes it is accompanied by dizziness, which indicates an inner ear or a central nervous system problem.

More importantly, nystagmus maybe a sign of a more serious underlying problem.

Causes

The direct cause of nystagmus is instability in the motor system that controls the eyes. There are a number of different causes of this instability, including:

• Heredity
• Poor development of eye control that may be caused by an eye disease or visual problem during infancy
• Albinism]]> (lack of skin pigmentation)
• Eye disorders, such as optic nerve degeneration or severe ]]>astigmatism]]> or ]]>nearsightedness]]>
• Diseases of the body, such as ]]>Meniere’s disease]]> (which involves balance problems), ]]>multiple sclerosis]]> , or ]]>stroke]]>
• Injury to the head or involving the body’s motor system
• Use of certain medications, such as lithium or antiseizure medications
• ]]>Alcohol]]> or ]]>drug use]]>
• Inner ear problems, such as infections or irritation

However, in some cases, the cause of nystagmus is unknown.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

The following factors increase your chance of developing nystagmus:

• A family member with nystagmus
• Albinism
• Eye disorders such as optic nerve degeneration, severe astigmatism, or nearsightedness
• Diseases of the body such as Meniere’s disease, multiple sclerosis, or stroke
• Injury to the head or involving the body’s motor system
• Use of certain medications, such as lithium or antiseizure medications
• Alcohol or drug use
• Infection of the inner ear

Symptoms

Other symptoms besides the eye movements may include:

• Sensitivity to light
• Difficulty seeing in darkness
• Vision problems
• Head held in a turned position
• Oscillopsia (feeling that the world is shaking or moving)
• Dizziness, which can affect balance

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. If nystagmus seems to be present, you may need:

• Full exam with an ophthalmologist (eye doctor)
• Ear exam, including a hearing test or a dizziness test
• Exam with a neurologist or other medical specialist

Tests may include the following:

• Visual examination of the inside of the eye with an ophthalmoscope
• Vision testing
• Eye movement recordings—to verify the type of nystagmus and determine the details of the movements
• Ear exam
• Neurologic exam
• Computerized tomography (CT)]]> —x-rays of the brain
• ]]>Magnetic resonance imaging (MRI)]]> —magnetic and radio waves used to make images of the brain

Magnetic Resonance Imaging

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The ophthalmologist will also look for other eye problems that may be related to the nystagmus, such as strabismus, ]]>cataracts]]> , or abnormality of the optic nerves or retina. The ear specialist will look for signs of ear infection, and for worsening of the nystagmus with head positions.

Treatment

Talk with your doctor about the best treatment plan for you. Removal of the cause of nystagmus can sometimes eliminate the problem, for example discontinuing a medication or stopping alcohol or drug use. However, nystagmus often is a permanent condition that can only be reduced and not eliminated. Treatment options to reduce nystagmus and improve vision as a result include the following:

• Prisms, tints, eyeglasses, or contact lenses
• Adopting a particular angle of vision where the nystagmus is reduced (eg, holding the head in a certain position)
• Vibratory stimulation of the face and neck
• Certain medications for certain types of nystagmus, including botox (botulinum toxin) injections]]> to relax the eye muscles
• Surgery on the eye muscles

Low-vision aids can often help improve vision. They may include large print or high contrast materials, good lighting, and magnifying devices.

Prevention

There is no known way to prevent nystagmus.