Coloboma describes a condition in which part of the eye structure misses from birth.
Coloboma of the eye is caused by embryonal abnormalities. It appears when the eyes of the fetus do not develop correctly. They take shape in the beginning of pregnancy and usually finish their development around week eight. In the beginning, they look like small ‘pimples’ in which the eyes gradually close, leaving only a small crack, which is needed for blood flow to those parts of the eye that are still in the process of development. In the final stage of development, this crack also closes. This is the place where coloboma can occur, if the crack doesn’t fully fuse.
Coloboma of the eye is not a hereditary condition, even though it is not impossible for people who carry one gene to have this condition. A coloboma can occur with some congenital diseases and other malformations.
Coloboma can affect one or both eyes. There are different types according to the affected part of the eye:
- Coloboma of the eyelid
- Coloboma of the lens
- Macular coloboma
- Coloboma of the optic nerve
- Uveal coloboma – affects the iris, the colored part of the eye
- Coloboma of the retina
Some types of coloboma can cause vision loss, depending on their degree.
Sometimes children with coloboma have a heightened sensitivity to light.
Treatment of coloboma depends on the person and type of coloboma.