Nystagmus is a condition in which the eyes make involuntary, repetitive movements. When this happens, both eyes are unable to hold a steady focus to see objects clearly. Some patients adopt an unusual head posture, turn or tilt to find a quiet position that dampens the movement.
The condition affects about one in 5,000 people.
There are three common types of nystagmus:
Congenital. Congenital nystagmus often develops by two or three months of age. The eyes tend to move horizontally, but can have associated vertical and rotational components.
Spasmus nutans. Spasmus nutans nystagmus tends to begin between six months and three years of age, associated with a "bobbing" movement of the head. It resolves itself between ages two and eight. As a result, it usually doesn't require treatment. The eyes may move in any direction with this type of nystagmus.
Acquired. Acquired nystagmus develops later in childhood or in adulthood. Although the cause is generally unknown, it may be the result of alcohol or drug toxicity, metabolic disorders, disorders of the central nervous system, tumors or stroke.
In a normal eye, the muscles that control eye movement receive a steady signal that results in smooth, controlled movement.
With nystagmus, the eye muscles receive a pulsating signal that results in involuntary shaking of the eyes, making it difficult to see objects clearly.
Nystagmus may be associated with:
- Central nervous system disease
- Congenital cataracts or any other ocular condition that reduces vision
Nystagmus is often diagnosed with an eye exam, and observation of the characteristic eye movements.
Other diagnostic tests may include:
- Videonystagmography, which are infrared recordings of eye movement
- Orthoptic sensori-motor, which tests how the eyes move and work together
- Optical coherence tomography, which takes cross-section images of the optic nerve and retina
- Magnetic resonance imaging (MRI) of the central nervous system
- Clinical videography
- Vision testing and refraction to determine visual strength
Expectations in the treatment of nystagmus have long been pessimistic. Medications to dampen the eye movement can have significant depressive side effects.
Surgery has been applied to either reduce the range of the eye movement (known as amplitude) or to reposition the muscles to allow a single quiet zone (the null point). This allows the patient to see without having to hold their head unnaturally.
These procedures have limited benefits because the twitching muscles remain attached to the eye.
In 2002, a surgical approach to treat the condition known as a sub-total anterior extirpation (also known as the Sinskey Anterior Extirpation) was reported.
What is different about this approach is that the front portion of the muscles are removed for maximum dampening of the movement. Early experience revealed a reduction in nystagmus, as well as improvements in voluntary eye movement and strabismus (lazy eye).
Dr. Robert Lingua at the UC Irvine Health Gavin Herbert Eye Institute was the first surgeon to apply this technique to children with nystagmus, operating on patients as young as one year old. The procedure has resulted in a near-surgical cure of nystagmus, which is determined by examining eye movement with infrared video.
In the last three years, this technique has advanced to preserve eye movements despite anterior extirpation, and has greatly reduced the incidence of secondary surgery to improve alignment.
A patient's experience
Grace Nassar was just three months old when her parents were told that Grace had nystagmus and could become functionally blind.
Grace was studying braille and walking with a cane when an acquaintance recommended the UC Irvine Health Gavin Herbert Eye Institute. As a result, seven-year-old Grace sees the world with new eyes.
Want to learn more? Call us at 949-824-2020.