In a patient with stenosis of the left internal carotid artery acute amaurosis of the left eye was observed after carotid arteriography. The macular branches of the central retinal artery and of the cilioretinal artery were obliterated by embolic material. Two further patients with carotid occlusion and stenosis, in whom spontaneous loss of vision occured, are presented. In such cases the diagnosis may be made with comparable accuracy by other methods, such as ophthalmodynamometry or angioscintigraphy, which entail risk to the patient.