Coloboma is a group of eye conditions where normal eye tissue in or around the eyes is missing from birth. It is also defined as an abnormal eye development caused by improper closure of the optic fissure. It occurs in approximately 1 of 10,000 live births in U.S.A. and can also cause vision loss.The term coloboma originates from a Greek word which means “curtailed”.
Coloboma can be classified into different groups depending on the part of the eye which is missing. These generally affect the following parts of the eyes:
- Uvea
- Optic nerve
- Macula
- Lens
- Eyelids
Causes of Uveal Coloboma
Most researchers tend to believe that uveal coloboma is genetically determined. This means that the coloboma was primarily caused by a gene that was deformed at the time of early eye formation and development. In some cases, coloboma is a part of a genetic syndrome that has a known genetics. For example, coloboma is a part of CHARGE syndrome that is associated with a complete deletion, or a change in a gene known as CHD7.
Scientists have found most of the genes which are associated with coloboma. However, many are yet to be discovered. The information regarding these genes are stored in the National Library of Medicine’s Genetics Home Reference.
Few reasearchers have proposed a new theory that holds environmental factors responsible for developing coloboma in animals and humans. One of the examples is alcohol consumption during pregnancy can develop coloboma.
Symptoms of Uveal Coloboma
There symptoms of uveal coloboma depend on the location and amount of the absent tissue. So, there may or may not be specific symptoms related to uveal coloboma. Individuals with an affected optic nerve and macula may have a reduced vision. Those with an affected retina may exhibit a condition called “field defect“. Field defect means that the affected individual experiences reduced vision in a specific location.
