Clinical and Doppler sonographic findings on the internal carotid artery of 218 patients with acute central retinal artery obstruction (42), branch retinal artery obstruction (43), anterior ischemic optic neuropathy (AION) (51), amaurosis fugax (AF) (21), and retinal vein occlusions (61) were evaluated. The most prominent finding was that only 1 out of 51 patients with AION and none of 61 patients with retinal vein occlusions showed a relevant stenosis or occlusion of the internal carotid artery. In contrast, however, patients with acute central retinal artery obstruction and branch retinal artery obstruction and those with AF revealed stenoses or occlusions of the internal carotid artery in approximative one-third to one-fourth of the cases. No excavation of the optic disc (cup) occurred in patients' eyes affected by AION or in the other eye. Fourteen of 51 patients with AION showed a "stuttering progression" of their visual function. The patients with progressive loss of vision were significantly younger on average than patients with permanent visual loss due to AION. Some of these cases with progressive field defects revealed an increase in edema of the optic discs and in hemorrhages. Patients with acute central retinal artery obstruction showed very high blood pressure values more often than patients with AION. Retinal emboli (Holenhorst plaques) were very often seen in patients with branch retinal artery obstruction (in 29 of 43 patients; 67%). However, they rarely occurred in patients with acute central retinal artery obstruction (5 of 42 patients). Only 1 of 51 cases with AION showed retinal emboli.