A coloboma is a defect in the iris of the eye. It can appear as a black notch of varying depth at the edge of the pupil, giving the pupil an irregular shape. Coloboma is a congenital iris defect. Sometimes eye surgery or trauma can cause a defect that looks like a coloboma.
Review Date 12/9/2021
Updated 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.