Ischemic optic neuropathy: a complication of cardiopulmonary bypass surgery.

Ischemic optic neuropathy followed cardiopulmonary bypass surgery in the postoperative period in 7 of 7685 consecutive procedures. Th visual loss was unilateral in four patients and bilateral in three and there was little improvement. This ischemic infarction of the optic nerve disk was attributed to hypotension, hypothermia, and activation of certain complement factors by the bypass procedure.