[Prepapillary arterial loop and retinal arterial branch occlusion].

Preretinal arterial loops are congenital vascular anomalies that originate from a main branch of the central retinal artery on the optic disc. These arterial loops are usually unilateral and asymptomatic, but they can be associated with retinal artery branch occlusion. We report one case of inferior temporal retinal artery occlusion in a patient with preretinal arterial loops. Two different mechanisms are thought to be the cause of occlusion: twisting of the loop or thrombosis.