Optic nerve hypoplasia and colobomatous defects.

The case of a 21-year-old woman with an optic nerve head coloboma and optic pit in one eye, a hypoplastic optic nerve head in the second eye, and a small retinochoroidal coloboma in each eye is presented. The probable etiology is some unknown insult involving several ocular embryonic structures and occurring during the 11-mm to 20-mm stage of development. The occurrence of these multiple anomalies in the same patient lends further support to the theory that optic disc colobomas and optic nerve hypoplasia represent a spectrum of developmental anomalies of the optic nerve.