Optic disc doubling.

Many developmental defects can simulate the optic disc (optic disc pseudodoubling). True optic disc duplication with 2 independent retinal vasculatures is rare. Associated optic nerve duplication is rarer still and seen in lower vertebrates. We report a rare case of unilateral double optic discs with a single optic nerve in the left eye of a 41-year-old man, otherwise asymptomatic in the affected eye.