coloboma

A coloboma is a gap in part of the structures of the eye and it can be large or small, normally found in the bottom part of the eye. It is caused when a baby’s eyes does not develop properly during pregnancy and this condition occurs in about 1 in 10,000 births. Coloboma can affect one eye (unilateral) or both eyes (bilateral).

If hospital staff suspect a child has a coloboma, which is normally first noticed by the possible keyhole-like shape of the pupil, then an ophthalmologist will carry out a full and thorough eye examination.

The effect coloboma has on vision depends on which part of the eye is affected and how big the gap is. Most commonly coloboma only affects the iris. Children with this type of Coloboma often have fairly good vision. If the coloboma goes further back into the eye then the child may have more visual problems, especially if the retina is involved. If this has happened then central vision may be affected. Coloboma may affect one eye more than the other, so one eye may have better vision than the other.

Most cases of coloboma appear without any previous family history but in some families coloboma can be inherited. The genetic factor responsible for most cases of coloboma has not yet been identified. Research is on-going to identify genes and any environmental factors that may cause coloboma.

At present there is no treatment for coloboma. Specialist care is given at hospitals during the early years to monitor the effects of the coloboma and the frequency of these checks will depend on the child’s needs. Children who have coloboma can be more at risk of glaucoma and retinal detachment and there are treatments for both of these conditions.

More detailed information can be found at the RNIB website.