A cat eye is a type of coloboma. Any defect in the iris that allows light to enter the eye, other than through the pupil, is called a coloboma. An extra hole or slit may be present from birth, or may result from trauma. Colobomas may also exist in the eyelid, a defect which interrupts the border of the eyelid.
Review Date: 11/4/2015
Reviewed By: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.