Seventy cases of retinal embolism showed cholesterol and platelet-fibrin emboli, usually from a carotid source, and calcific emboli, usually from a cardiac source, in that order of frequency. A marked preference for the temporal circulation, and particularly for the posterior pole, was observed with all the types of emboli. Only patients with cholesterol embolism complained of amaurosis fugax, whereas all the patients with calcific or stationary platelet-fibrin emboli experienced permanent visual loss. Visual field defects were characteristic of those seen with degeneration of the retinal axons. Collateral vessels usually developed with emboli to the arterioles of the disc and peripapillary region. Periarteriolar sheathing, as well as late fluorescein leakage from the impacted site, seemed to follow the cases of more severe endothelial damage due to cholesterol embolism. Subtotal nonprogressive ischemia ensued in relationship to post-embolic sheathing, which eventually disappeared, leaving a narrowed arteriole.