Definition of Nystagmus

Nystagmus affects approximately one in 1,000 people, yet this eye disorder is still something of a mystery. Research is ongoing to understand more about the causes and possible cures for nystagmus, but full answers are probably still decades away. Much has been learned already, though, to help those who suffer from this condition.

Features

• Nystagmus is the name for involuntary eye movement. Generally the eyes move from side to side, but in some cases they move up and down or even in circles. This means a person with nystagmus has very poor vision. Most would be classified as partly sighted, and some would classify as blind. The degree of vision tends to vary during the day, as stress or fatigue can make vision worse.

Types

• When nystagmus appears by 12 months of age, it's called congenital, or early-onset, nystagmus. Congenital nystagmus can be further divided into two types. Manifest nystagmus is always present. Latent nystagmus only appears when one eye is covered.

  Nystagmus can appear later in life, and then it's referred to as acquired nystagmus. This type is generally a result of another issue such as stroke or trauma.

Causes

• Nystagmus can be a symptom of an underlying neurological issue, so someone with nystagmus should always be tested by an ophthalmologist or neurologist when symptoms first appear. Congenital nystagmus may be a result of a defect in the structure of the eye, or it may come along with cataracts or glaucoma. It's a common symptom of albinism and Down's Syndrome.

  Some forms of congenital nystagmus can be inherited, and sometimes no underlying cause can be found.

  Acquired nystagmus can appear as a result of trauma to the head or from neurological issues such as multiple sclerosis, stroke or brain tumors. It can also be brought on by drug abuse.

Effects

• Nystagmus is not painful, but the extremely poor vision that results affects most areas of a sufferer's life. Reading is difficult for those with nystagmus, and they may need accommodations in school such as extra time for taking tests or being provided with large-print materials. They may have trouble looking at computer screens, as well.

  Depth perception is generally off in those with nystagmus. They may be able to see better by looking at things from an angle, so many will hold their head at a tilt. Many people with nystagmus can't legally drive.

  The constant effort involved in trying to see means that nystagmus sufferers may be tired often, which causes a vicious cycle, since fatigue makes their vision worse. They may have trouble maintaining eye contact with others, and they may suffer from low self-esteem.

  Those with congenital nystagmus typically adjust to the effects better than those who acquire it later in life.

Treatment

• There is no known cure for nystagmus. Since most sufferers have vision difficulties apart from the nystagmus, glasses or contacts will improve their vision but won't fix the nystagmus. In a few cases, surgery on the muscles that move the eye may help with the head tilt.

  Some research has been done on bio-feedback techniques to try to train those with nystagmus to hold their eyes still, but the results have been inconclusive. A few researchers are looking into drugs to help, but nothing has been approved.

  The effects of congenital nystagmus may be reduced if children are given lots of visual stimulation before age 5 or 6. In particular, toy cars or train sets that cause them to follow an object with their eyes may help.