Definition:
Coloboma of the iris is a hole or defect of the iris of the eye. Most coloboma are present since birth (congenital).
Alternative Names:
Considerations:
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 Ghost image
The defect may include the retina, choroid, or optic nerve. Colobomas are generally diagnosed at, or shortly after birth.
Common Causes:
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.
References:
Olitsky SE, Hug D, Smith LP. Abnormalities of pupil and iris. In: Kliegman RM, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 621. Guercio JR, Martyn LJ. Congenital malformations of the eye and orbit. Otolaryngol Clin N Am. 2007;40:113-140.
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