Although carotid endarterectomy (CE) is recommended in appropriate patients with bifurcation atheroma for the prevention of stroke, these patients are also at risk for visual loss, either temporary or permanent. The presentations of patients undergoing 512 consecutive CEs were reviewed to determine the preoperative frequency and risks of ocular disturbances. Visual symptoms occurred in 131 patients (25%). Temporary, monocular blindness (amaurosis fugax, AF) was reported by 99 patients (19%). Concomitant neurologic symptoms were present in 33 (33%) of the patients with AF, and carotid artery stenoses of greater than 75% diameter were documented in 82 (83%) of these patients. No visual deficits were observed following operation. Permanent visual loss ranging from scotoma to complete blindness was documented in 32 patients (6.2%). The permanent deficits were due to retinal artery occlusions (RAO) in 20 patients (4%), ischemic optic neuropathy (ION) in eight patients (1.5%), and homonymous hemianopsia (HH) in four patients (0.7%). Visual loss occurred without any warning in 27 of these 32 cases (84%). The five cases with warning had multiple episodes of AF and then sustained RAO and blindness. Neurologic symptoms occurred concomitantly but not prior to visual symptoms in 7 of the 12 patients (58%) with ION and HH. Stenoses greater than 75% were present in 22 of 32 cases (69%) and in every case of ION. Operation had no effect on the visual deficit. Permanent visual loss occurred in a significant number of patients with carotid atheroma (6.2%). Warning in the form of visual prodroma is uncommon in these patients (16%).(ABSTRACT TRUNCATED AT 250 WORDS)