Optic nerve pit.
Optic nerve pits are an uncommon congenital anomaly of the optic nerve head. Pits are generally recognized to represent an atypical form of optic nerve coloboma. The appearance of optic nerve pits can be quite variable and may simulate other anomalies of the optic nerve head, such as glaucoma or optic nerve tumor. Visual loss is present in a significant number of cases. Arcuate scotomas and a serous macular detachment have been associated with pits of the optic nerve. The mechanism for development of the serous maculopathy is not well understood.