Four patients with unilateral Purtscher's retinopathy are described. Fluorescein angiography demonstrated impaired arteriolar flow, capillary non-perfusion, venous staining, retinal edema, and optic disc edema. Resolution exceeded three months with variable degrees of permanent visual loss, optic atrophy, and pigment epithelial alteration. The pathogenesis of Purtscher's retinopathy is unknown. Arterial embolization, possibly air from the lungs, seems to be the most plausible explanation.