Eleven patients who experienced significant loss of vision after transsphenoidal surgery are reported on. The mechanisms involved in these visual complications include direct injury or devascularization of the optic apparatus, fracture of the orbit, postoperative hematoma, cerebral vasospasm, and prolapse of the optic chiasm into an empty sella. Factors that may increase the risk of visual complications include the presence of a pituitary macroadenoma, previous visual impairment, a "bottleneck" or dumbbell-shaped tumor, previous surgery and/or radiation therapy, and, possibly, use of a lumbar subarachnoid catheter during operation. A practical approach to the management and avoidance of these complications is presented.