Coloboma
Background
Coloboma means that there is a gap, or cleft, in one of the structures of the eye. This is the results of congenital malformation, with a portion of the eye failing to complete its growth and fuse together, so leaving a cleft. Different parts of the eye may be affected, including the lens, choroid and optic nerve, although the iris is most commonly involved, giving a keyhole shaped pupil.