Coloboma of the iris is a hole or defect of the iris of the eye. Most colobomas are present since birth (congenital).
Coloboma of the iris can look like a second pupil or a black notch at the edge of the pupil. This gives the pupil an irregular shape. It can also appear as a split in the iris from the pupil to the edge of the iris.
A small coloboma (especially if it is not attached to the pupil) may allow a second image to focus on the back of the eye. This may cause:
If it is congenital, the defect may include the retina, choroid, or optic nerve.
Most colobomas are diagnosed at birth or shortly afterward.
Coloboma can occur due to:
Most cases of coloboma have no known cause and are not related to other abnormalities. Some are due to a specific genetic defect. A small number of people with coloboma have other inherited developmental problems.
Contact your health care provider if:
In addition to your child, you may also need to see an eye specialist (ophthalmologist).
Your provider will take a medical history and do an exam.
Since the problem is most often diagnosed in infants, knowing about the family history is very important.
The provider will do a detailed eye exam that includes looking into the back of the eye while the eye is dilated. An MRI of the brain, eyes, and connecting nerves may be done if other problems are suspected.
Reviewed By: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 09/16/2019.