CT scanning can be of great value in evaluating optic nerve colobomas, particularly in clinical situations in which corneal, lenticular, vitreal, or other opacities hinder visualization of the optic disc. Experience with the patients presented here demonstrates that CT scanning is useful in the assessment of the presence and size of classic colobomas, morning glory anomaly, and microphthalmos with cyst. It is also of value in assessing associated ocular defects such as microphthalmos, shallow anterior chamber, and atrophic ciliary body.