Coloboma of the iris

Definition
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.

Considerations
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.

Common Causes

     
  • Cat-eye syndrome  
  • Trisomy 13  
  • Trisomy 18  
  • Marfan’s syndrome  
  • Rubinstein-Taybi syndrome  
  • Sturge-Weber disease  
  • Basal cell nevus syndrome  
  • Variation of normal (some colobomas can be inherited as an autosomal dominant trait)

Home Care

Colobomas are generally diagnosed at, or shortly after birth. There is no home care.

Call your health care provider if

     
  • You notice that your child has what appears to be a hole in the iris or an unusual-shaped pupil.  
  • Vision becomes blurred, or decreased vision is noted.

Note: It is appropriate to see an ophthalmologist for vision problems. Your primary health care provider may need to help rule out disorders associated with coloboma of the iris.

What to expect at your health care provider’s office

The medical history will be obtained and a physical examination performed.

The patient is usually an infant, and the family history will be most important.

The physical examination will include a detailed eye examination. A dilated exam of the inside of the eye should be done. Other tests may include MRI imaging of the brain and nerves connecting the eye to the brain.

After seeing your health care provider:
You may want to add a diagnosis related to a coloboma to your personal medical record.

Johns Hopkins patient information

Last revised: December 7, 2012
by Sharon M. Smith, M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.