A review of 100 cases of carotid-ophthalmic aneurysms has been undertaken to detail their associated visual signs and the effect of surgical treatment on visual function. Thirty-two patients (25 of 61 with intact aneurysms, 7 of 39 with ruptured aneurysms) had visual abnormalities. Visual field abnormalities were found in all these patients, and visual acuity was impaired in every patient except 1. These aneurysms were often difficult to treat surgically, and a wide variety of techniques were used. A satisfactory neurological result was obtained in 26 of the 32 patients (81%), with a satisfactory visual result in 24 of the 29 survivors (83%).