Aniridia

What is aniridia?

Aniridia is a serious and rare genetic eye disorder that affects the colored part of the eye (iris). Aniridia means lack of an iris. With this condition, the iris is partly or fully gone. The pupil is abnormally large and may be oddly shaped. This condition often affects both eyes. It can also affect the cornea, anterior chamber, lens, retina, and optic nerve. Some of these problems are present from birth (congenital), while others may happen later in life.

The iris controls the size of your pupil and the amount of light that enters your eye. Problems with other parts of your eye may cause issues that are more significant than aniridia.

Aniridia can occur as a single abnormality. Or in some cases, it may be one of several symptoms linked to other underlying conditions. It affects males and females about equally.

What causes aniridia?

Experts think many cases happen because of a change (mutation) in the gene called PAX6. PAX6 is part of the genetic information you pass to your children. This gene is key for eye health and development. If the PAX6 gene doesn’t work normally, your eyes may not develop correctly. This may cause aniridia.

Who is at risk for aniridia?

If someone in your family has aniridia, you have an increased risk for it. Most forms of it are autosomal dominant. That means that a child of a parent with aniridia has a 50 out of 100 chance of having it. Some people who have aniridia don’t have any family members with the condition.

What are the symptoms of aniridia?

Aniridia can cause many symptoms, such as:

Poor vision (not always present)
More sensitivity to light
Fast, uncontrolled, shaking "to and fro" eye movements (nystagmus)
Eyes don't line up (strabismus)

Often this condition affects only your eyes. But some people have aniridia along with other symptoms. The most common are Wilms tumor (a kidney tumor), genitourinary problems, and intellectual disabilities. Together with aniridia, these are known as WAGR (Wilms tumor-aniridia-genital anomalies-retardation (intellectual disability)) syndrome. In rare cases, aniridia can happen with Gillespie syndrome. This is a rare syndrome that affects the eyes and the brain. People with this disorder also have intellectual disabilities and balance problems.

How is aniridia diagnosed?

Diagnosis often happens at birth or a young age. A healthcare provider will ask about your child’s health history and do a physical exam. This includes an eye exam. The healthcare provider may be able to see a small rim of the iris when looking at your child’s eye. In some cases, other tests may be needed to help confirm the diagnosis.

How is aniridia treated?

Treatment is usually directed at treating and improving vision. Children with this condition will need regular eye exams to monitor their vision and to carefully watch for complications. These may include cataracts and glaucoma. These problems may need their own specific treatments.

Many children with aniridia need special glasses. These are to protect their eyes from sunlight and injury. Glasses can also help correct any loss of vision sharpness. Some people may be able to wear a special type of painted soft contact lens. These can help to reduce glare, sharpen vision, and improve how the eyes look.

An eye care provider may also treat aniridia by surgically replacing the iris with an artificial iris. This procedure for both adults and children may help reduce light sensitivity and glare. It may also improve how the eye looks.

What are possible complications of aniridia?

Aniridia can cause severe problems, which may happen soon after birth or later in life. Some of these health conditions are also common in older adults who don’t have aniridia. But for someone with aniridia, they typically occur at a younger age. Complications can include:

Aniridia-related keratopathy. The cornea becomes less clear. It makes vision worse.
Glaucoma. This is elevated pressure in the eye. It happens most often in teens with aniridia.
Cataract. This is clouding of the lenses of the eyes. This can make it harder to see.
Problems with the optic nerve. This nerve sends visual information to the brain.
Retinal detachment. The retina is the light-sensitive part on the back of the eye. Retinal detachment can cause severe vision loss without surgery to fix it.

These problems can cause many symptoms, including:

Blurred vision
Blindness in part of the field of vision
Flashes of light in the eye
Eye pain

Your child might need medicated eye drops or surgery to treat these problems.

How to manage aniridia

Most children with this condition will be able to go to a normal school. Your child may need extra support in the classroom to cope with visual issues.

You may find a support group helpful. Aniridia Foundation International is a support group for people with aniridia and their families.

When should I call my healthcare provider?

Call 911right away if your child has sudden vision loss or sudden eye pain.

Key points about aniridia

Aniridia is a serious and rare genetic eye disorder. The iris is partly or fully gone, often in both eyes. It can also affect other parts of the eye.
Your child may have certain problems from birth, such as increased light sensitivity.
Other eye problems may develop later, such as cataracts or glaucoma.
Your child may need to wear special contact lenses or glasses to protect their eyes.
Regular eye checkups are needed. Your child's eye care provider will check visual sharpness and watch for problems.
Surgery may be needed.