Arteriovenous communication in the orbit.

Arteriovenous malformations (AVMs) are anomalous communications between arterial and venous systems without interposed capillaries. These lesions are rarely entirely intraorbital. A case of an arteriovenous communication between branches of the internal and external carotid arterial circulations and the ophthalmic veins located within the orbit is reported. Treatment with embolization resulted in a branch retinal artery occlusion. Attempted direct arterial occlusion of a dural-based fistula of the eye is a risky procedure. If embolized, AVMs should probably be approached from the venous side, if at all.