A coloboma is a gap or cleft of the tissue in or around the eye. It generally occurs as a result of disruption in the development of the eye early in pregnancy. Coloboma can affect the eyelid, lens, iris, retina or optic nerve. It can be unilateral, affecting one eye, or bilateral, affection both eyes. Coloboma is generally thought to be caused by a defective gene; although most cases appear without any known cause or any previous family history. Coloboma of the iris, while at times quite conspicuous, does not impair vision. Visual loss occurs when the coloboma affects the macula or optic nerve. High myopia is often associated with coloboma.


Functional Characteristics

There is a wide range of visual function among individuals with coloboma. The location and size of coloboma determines the type and degree of visual impairment.

Currently, there are no medications or surgeries that can correct coloboma. However, it is important for children with coloboma to be followed by an eye care professional to:

  • Monitor the need for glasses to correct any refractive errors
  • Treat amblyopia (weakness in one eye)  if it occurs, usually by patching or using eye drops
  • Prescribe low vision devices such as magnifiers as needed
  • Prescribe sunglasses to reduce light-sensitivity as needed


Teachers of the visually impaired can help children with coloboma learn to compensate for their visual impairments and maximize the vision they have.

There are also options to change the appearance of the eye in some cases with contact lenses or surgery.

Associated Conditions

Coloboma usually occurs in isolation; however, a small percentage of people with coloboma have other associated conditions, including other eye conditions (see above). Coloboma can be associated with anomalies involving other parts of the body. Some of these conditions may be minor, such as skin tags by the ear, while others can be major health concerns, such as heart or kidney defects. There are few genetic syndromes that can be associated with coloboma -the most common is CHARGE syndrome. Retinal detachment is a blinding complication of coloboma.




National Eye Institute

National Institutes of Health

2020 Vision Place

Bethesda, MD 20892–3655



Family Connect

A website for parents of children with visual impairments developed by American Foundation for the Blind and National Association of Parents of Children with Visual Impairments


Delta Gamma Center for Children with Visual Impairments

1750 S. Big Bend Blvd.

Richmond Heights, MO  63117




Delta Gamma Center for Children with Visual Impairments acknowledges the following sources of information for this summary:

American Association for Pediatric Ophthalmology and Strabismus. (2011). Coloboma. Retrieved January 22, 2011, from

 National Eye Institute. (2009). Coloboma. Retrieved November 23, 2010, from

Professional Edit, Steven D. Goodrich, M.D. Pediatric Ophthalmologist