Typical Coloboma

Typical coloboma are due to some interference with the normal closure of the embryonic cleft, the aberration lying primarily in the epiblast of the optic cup. They occur between the time of invagination of the optic vesicle and closure of the cleft(between 7 and 14 mm stage of development), and include a whole series of anomalies varying from a complete defect involving the optic disc, the retina and choroid, the ciliary body, the iris, and even the lens to a minimal localized and partial failure of closure. The authors have experienced 2 cases of the typical coloboma of the iris, the zonule, the, ciliary body, the choroid and retina, the optic nerve head, and the lens, so briefly reviewed the litera.tures relating to typical coloboma.