Aniridia, an eye disorder that can affect one or both eyes, is a condition where all or part of the iris -- the colored part of the eye -- is missing. While not all children born with aniridia have poor vision, since the pupil of the eye is larger, sensitivity to light and glare are common. Other eye problems often develop when aniridia is present. That's why it's important to have your child's eyes regularly examined by an ophthalmologist. This article will help you understand more about the disorder.

Role of Genes

Aniridia is a chromosomal abnormality that occurs during the 12^th to 14^th week of pregnancy while the eye is developing. The affected gene is responsible for making a protein needed in the early development stages of the eyes, brain, and central nervous system.

If you or the other parent has aniridia, there is a 50 percent chance that each child you have could inherit the disorder. Sometimes, though, a child is born with aniridia even if neither parent has the disorder.

Effect on Vision

Although it may look like the eye has no iris, children with aniridia have some type of iris tissue in their eye. However, this small rim of tissue often is visible only to an ophthalmologist who uses a special instrument to examine the front part of the eye.

While the absence of iris tissue doesn't always affect vision, other eye problems can occur. Many children with aniridia develop nystagmus (involuntary eye movement), cataracts, or glaucoma. Cataracts (cloudy area in the lens) affect 50 to 85 percent of individuals with aniridia, causing blurred vision. They can be present at birth or develop later in childhood. When glaucoma (increased pressure in the eye) occurs, the condition usually develops by early adolescence.

Sometimes other health problems occur along with anirida. The condition is usually present in infants born with WAGR syndrome -- a rare genetic disorder. Other symptoms a child with WAGR syndrome can have include developmental delays, mental retardation, genital and urinary problems, and Wilms' tumor -- a kidney cancer that occurs mostly in children.

Gillespie syndrome is another rare disorder in which the iris of the eye fails to develop completely before birth. Although nystagmus, learning disabilities, speech problems, mental retardation, and balance problems can occur with Gillespie syndrome, individuals do not develop cataracts or glaucoma -- eye problems that often accompany aniridia.

Treatment Options

Both children and adults with anirida require regular eye exams. Depending on the severity and accompanying vision problems, treatment may include:

• Corrective lenses. Your eye doctor may prescribe glasses for you or your child with aniridia to improve visual acuity. Tinted lenses help reduce glare from sunlight.

• Eye drops and oral medications to control intraocular pressure if glaucoma develops.

• Removal of the lens if cataracts are present. An intraocular lens be implanted to replace the natural lens. In some cases, an artificial iris may be placed in the eye following cataract removal. Eyeglasses may be needed if intraocular lenses aren't appropriate.

• Painted soft contact lenses to improve cosmetic appearance and reduce light sensitivity.

• Low-vision aids when eyesight is mildly impaired.

If you have other questions about this or other eye conditions, contact an experienced ophthalmologist like Jo Johnson, M.D.