Coloboma
| Coloboma | |
|---|---|
 |
|
| Classification and external resources | |
| Specialty | Ophthalmology |
| ICD-10 | Q10.3, Q12.2, Q13.0, Q14.2, Q14.8 |
| ICD-9-CM | 377.23, 743.4, 743.46, 743.52, 743.57 |
| OMIM | 120200 |
| DiseasesDB | 29894 |
| MedlinePlus | 003318 |
| Patient UK | Coloboma |
| MeSH | D003103 |
A coloboma (from the Greek koloboma, meaning defect) is a hole in one of the structures of the eye, such as the iris, retina, choroid, or optic disc. The hole is present from birth and can be caused when a gap called the choroid fissure, which is present during early stages of prenatal development, fails to close up completely before a child is born. The classical description in medical literature is of a key-hole shaped defect. A coloboma can occur in one eye (unilateral) or both eyes (bilateral). Most cases of coloboma affect only the iris. People with coloboma may have no vision problems or may be blind, depending on severity. It affects less than one in every 10,000 births.
The effects a coloboma has on the vision can be mild or more severe depending on the size and location of the gap. If, for example, only a small part of the iris is missing, vision may be normal, whereas if a large part of the retina or optic nerve is missing, vision may be poor and a large part of the visual field may be missing. This is more likely to cause problems with mobility if the lower visual field is absent. Other conditions can be associated with a coloboma. Sometimes, the eye may be reduced in size, a condition called microphthalmia. Glaucoma, nystagmus, scotoma, or strabismus may also occur.
Colobomas can be associated with a mutation in the PAX2 gene.
Eye abnormalities have been shown to occur in over 90% of children with fetal alcohol syndrome.
Other ocular malformations that include coloboma or are related to it:
The number of cases is around 0.5 to 0.7 per 10,000 births, making it a relatively rare condition.
Colobomas of the iris may be treated in a number of ways. A simple cosmetic solution is a specialized cosmetic contact lens with an artificial pupil aperture. Surgical repair of the iris defect is also possible. Surgeons can close the defect by stitching in some cases. More recently artificial iris prosthetic devices such as the Human Optics artificial iris have been used successfully by specialist surgeons. This device cannot be used if the natural lens is in place and is not suitable for children. Suture repair is a better option where the lens is still present.
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Wikipedia