Nystagmus is the name for a condition in which the eyes make uncontrolled, repetitive movements. The American Nystagmus Network reports about one person in every several thousand have nystagmus, but the incidence may be as high as one in 630. The eyes may move side to side, up and down, in circular fashion or drift slowly, all of which affect the patient’s ability to hold a steady gaze. It is most common in early childhood (often present from birth) but one may acquire it in adulthood.
Nystagmus causes include neurological or developmental problems, trauma, stroke, multiple sclerosis, and medications. Treatment depends on the cause, but there is no cure at the moment; treatment helps relieve or manage symptoms. Surgery on the eye muscles may help reduce the need to turn the head to see but doesn’t stop the eye movement. Glasses and contacts can make it easier to see but don’t actually correct the condition.
What Is Nystagmus?
There are three primary forms of nystagmus, according to the American Optometric Association: infantile, spasmus nutans, and acquired nystagmus, and then we also have manifest and latent nystagmus. Infantile nystagmus usually develops by two to three months of age. It is likely to be associated with congenital conditions such as albinism, congenital cataract, and underdeveloped optic nerves. Some children don’t have an iris – the colored part of the eye. In this form, the eyes tend to swing horizontally.
Spasmus nutans usually occurs between the ages of six months and three years. Although the eyes may move in any direction, children with spasmus nutans often nod and tilt their heads in order to see. Children with spasmus nutans may grow out of this condition by the age of eight.
Acquired nystagmus may develop in older children or adults. Its causes are most likely central nervous system disorders, metabolic disorders, alcohol or drug toxicity.
Manifest nystagmus is constant, while latent nystagmus occurs only when covering the patient’s eye. Manifest and latent nystagmus can also occur together. In this case, the condition exists at all times but when the patient covers one eye, it becomes worse.
Nystagmus causes vary, but congenital problems are most common. In many cases, nystagmus results from another eye or medical condition and is primarily a symptom rather than a stand-alone condition. When people are tired or stressed, their symptoms may worsen. In some cases, the actual nystagmus cause is unknown.
Neurological and developmental conditions
These medical conditions account for the bulk of nystagmus conditions. Some children may not develop normal eye movement control. When the shape of the eye keeps light from being properly focused on the retina, the patient is said to have a refractive error. Nearsightedness and astigmatism (blurry vision) are refraction errors that may cause nystagmus.
Other nystagmus causes include albinism (lack of pigment in the skin, hair, and eyes) and congenital cataracts (clouding of the lens in the eye). Congenital problems that affect the development of the optic nerve may also result in nystagmus.
Inflammation in the inner ear is another nystagmus cause; it results in inflammation of the vestibular nerve, which affects balance.
Nystagmus may also be a side effect of some anti-epilepsy medications. Medications such as amphetamine, barbiturates, benzodiazepines and other sedatives may cause nystagmus.
Nutritional deficiencies can result in nystagmus. Lack of vitamin B1, which often occurs in alcoholism, can be one the many nystagmus causes.Beriberi is the term describing Vitamin B1 deficiency when it occurs from nutritional deficiencies without the presence of alcoholism.
Other possible nystagmus causes include concussion, myasthenia gravis, stroke, alcohol withdrawal syndrome and brain tumors – specifically neuroblastoma. Diseases or conditions that affect the retina of the eye may result in nystagmus.
Treatment of Nystagmus
Diagnosis of nystagmus is based on symptoms and visual acuity measurements. Although the eye movement is readily visible even to a layperson, a comprehensive visual examination is required to determine the degree and extent of the problem and any associated conditions such as nearsightedness.
Since nystagmus may be a symptom of another condition, patients are often referred to a primary care physician for other medical testings to identify the specific cause of nystagmus. Treatment options directly relate to the cause and include:
- Medicinal drugs. If nystagmus is caused by a treatable inflammatory condition of the inner ear – such as an infection – it may be treated with antibiotics and sometimes decongestants.
- Botox or Baclofen. Nystagmus often affects an individual’s vision by limiting clarity; the constantly moving eye makes it impossible to maintain a steady focus to get a clear image. Treatments that reduce nystagmic movements include the use of Botox or a medication called Baclofen. Botox is the same medication dermatologists use to treat wrinkles. It paralyzes the muscle to slow or prevent the eye movement. In both cases, results are likely to be temporary. However, one can repeat Botox injections.
- Biofeedback training may help some people with nystagmus.
- Glasses and contact lenses can improve the vision of people with nystagmus and make it less necessary to move or tilt the head in order to see better. Contact lenses offer the advantage that the lens moves with the eye instead of sweeping back and forth behind glasses, and may provide a better outcome than conventional glasses.
- Surgery is usually directed toward strengthening or weakening the eye muscles. It is sometimes part of the treatment of congenital nystagmus. Although acupuncture is a form of treatment, there is no clear scientific evidence to prove its effectiveness.
A Word of Ending…
Although nystagmus can affect people’s visual acuity, doctors do not usually consider it to be as serious as other eye conditions. With the exception of surgery, doctors focus the treatment on the conditions that result in nystagmus rather than the eye problem itself. In children, nystagmus may sometimes correct itself with age, but in many cases, it is a life-long condition. Regular eye exams can help identify nystagmus causes in the early stages and are also important to identify other and more serious visual problems such as glaucoma.