Coloboma of the iris

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Cat eye

Coloboma of the iris

Eye

Coloboma of the iris is a congenital (present since birth) defect of the iris of the eye. It is visible as a hole, split, or cleft in the iris.

Coloboma of the iris may appear as a black, round hole located in or adjacent to the iris (colored portion 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. 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 secondary image to focus on the back of the eye, causing a ghost image, blurred vision, or decreased visual acuity.

Coloboma may be associated with hereditary conditions, trauma to the eye, or eye surgery. The defect may extend to the retina, choroid, or optic nerve.

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

Review Date: 11/14/2005
Reviewed By: Edward B. Feinberg, MD, MPH, Professor and Chair, Department of Ophthalmology, Boston University School of Medicine, Boston, MA. Review provided by VeriMed Healthcare Network.