A 66-year-old woman with a history of left breast adenocarcinoma presented to the ophthalmologist clinic with a 6-months history of redness and swelling of her left eye. Patient denies recent trauma nor previous episode of symptoms of her left eye. On examination, left eye proptosis, conjunctiva slightly injection with corkscrew vessels associated with elevated intraocular pressure were observed. A diagnosis of carotid cavernous fistula was made after angiography. Carotid cavernous fistula is a result of abnormal vascular connection between internal carotid artery or external carotid artery and the cavernous sinus. This condition can occur either spontaneous or secondary to trauma. Disorder that exerting a mass effect on cavernous sinus such as neoplasm, infection should be considered in patients with carotid cavernous fistula. Current treatment of this condition includes embolization, surgery intervention or stereotactic radiosurgery. In this patient, stereotactic radiosurgery was suggested.