1. Direct carotid-cavernous sinus fistulas usually result from multi-trauma or head injuries. These patients are more likely to be seen at trauma based hospitals. 2. Ocular manifestations of direct carotid-cavernous sinus fistulas include exophthalmos, swollen eyelids, ocular pulsation, pulsating exophthalmos, conjunctival chemosis, arterialization of conjunctival vessels, exposure keratopathy, a bruit over the affected eye (heard by the patient as a swishing sound), diplopia, visual loss, and ophthalmoscopic abnormalities that include moderate dilation of retinal veins, optic disc swelling, and intraretinal hemorrhage. 3. The ultimate diagnostic test for direct carotid-cavernous sinus fistulas is cerebral arteriography of both the internal and external carotid arteries. 4. The optimal treatment of a direct carotid-cavernous sinus fistula is closure of the abnormal arteriovenous communication with preservation of internal carotid artery patency. Detachable, flow-guided balloons are presently used to close most direct carotid-cavernous sinus fistulas.