Nystagmus is an unintentional jittery movement of the eyes. Nystagmus usually involves both eyes and is often exaggerated by looking in a particular direction.

Alternative Names of Nystagmus are:

• BPPN
• Cupulolithiasis
• Labyrinthine Positional Nystagmus
• Paroxysmal Positional Nystagmus

Complications of Nystagmus

The inability to hold a steady gaze almost always results in some loss of visual acuity. The perception that stationary objects are moving (oscillopsia) and the loss of depth perception can cause individuals with nystagmus to lose their balance or appear clumsy. Nystagmus that comes on suddenly such as with a viral infection of the inner ear (viral labyrinthitis) is often associated with nausea and vomiting.

Causes of Nystagmus

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.

Signs & Symptoms of Nystagmus

Nystagmus is characterized by involuntary, repeated oscillations of one or both eyes, and the disorder often affects the nerves behind the eye and not the eye itself. Movements may be horizontal, vertical, circular, or a combination of various motions and speeds. Nystagmus affects people in varying ways and degrees. Although most affected people view objects as stationary because the brain is thought to make the necessary adjustments, many often have reduced acuity because of the challenge to maintain a fixed focus. People with nystagmus tend to see objects in lower contrast, and many experience problems with depth perception that affect balance and coordination. Some of those affected with the disorder tilt their heads or display nodding to compensate for the impairment or symptoms.

Many people with nystagmus are considered partially sighted; some are registered legally blind; and most are unable to drive. Generally, the faster the oscillation, the lower the visual acuity, and, conversely, the slower the movement, the higher the visual acuity. It is important to point out; however, that vision impairment may also be a result of other underlying visual problems. Most people with nystagmus have a null point, which is a specific viewing angle when eye movement is reduced and vision is improved. Affected people often develop a certain head posture or body posture such as sitting to one side of a television, movie screen, etc., in order to get the best view.

Diagnosis of Nystagmus

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

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.

Treatments of Nystagmus

• Sometimes, removal of the cause may cure nystagmus (e.g., medication). Often, however, nystagmus is permanent.
• The reduced vision may be improved with glasses and low vision aids. If the eyes are more stable looking in a certain direction, glasses with prisms or eye muscle surgery may improve the head position and allow better vision.

Prevention of Nystagmus

There is no known way to prevent nystagmus.

When to seek Medical Advice

Since nystagmus can be caused by tumors, stroke, and trauma or neurological disorder, any type of nystagmus must be evaluated by a qualified practitioner. The nystagmus can be a sign of a serious problem.