Congenital Abnormalities Of The Eyeball And Optic Nerve

We present six cases of congenital abnormalities of the eyeball and the optic nerve. Various genetic and acquired causes may impair the normal development of the eye; nevertheless the time of the insult is more determinant than the specific etiology.Microphthalmos is defined ''simple'' when the eye is small but anatomically normal, and ''complex'' when the eye is malformed. The complex microphthalmos may be divided into non colobomatous and colobomatous forms; coloboma is a congenital abnormality due to failure of the embryonic choroid fissure to close properly. Microphthalmos with cyst is a serious colobomatous malformation:the size of the eye and the cyst may vary and numerous systemic anomalies may be associated. Persistent hyperplastic primitive vitreous results when the hyaloid artery and the surrounding fibrovascular tissue fail to regress. Optic nerve hypoplasia is frequently associated with ocular, facial and encephalic anomalies; it is probably caused by an excessive degeneration of the optic nerve axons.Imaging studies are necessary to characterize ocular abnormalities. Ultrasonography represents the screening examination. CT is currently the technique of choice and 3D CT is useful when orbital and facial malformations coexist. MR provides better diagnosis of associated intracranial anomalies.