Coloboma of the iris is a hole or defect of the iris of the eye. Most coloboma are present since birth (congenital).

Coloboma of the iris may look like a black, round hole located in or next to the colored part of the eye (iris). It can look like a black notch of different depths 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 (specially if it is not attached to the pupil), may allow a second image to focus on the back of the eye, causing:

• Blurred vision
• Decreased visual acuity
• Ghost image

The defect may include the retina, choroid, or optic nerve.

Colobomas are generally diagnosed at, or shortly after birth.

Coloboma can occur due to:

• Eye surgery
• Inherited conditions
• Trauma to the eye

Most cases of coloboma have no known cause and are not related to other abnormalities. A small percentage of people with coloboma have other inherited developmental problems.