Most patients with arteriovenous fistula in the brain are asymptomatic. Depending on the site of the arteriovenous fistula, possible symptoms include: 1. If it occurs in the cavernous sinus area, the arteriovenous fistula is a supraocular venous drainage. Our normal supraocular vein is from the eye to the skull, once an arteriovenous fistula occurs, the drainage is from the skull to the eye, causing an increase in pressure in the eye, which can result in bulbar conjunctival congestion, swelling, protrusion of the eye, and even vision loss, which can be easily detected. Once found, many people will consult with the ophthalmology department, most people may have this symptom is the problem of the eye itself, a small number of people is caused by arteriovenous fistula, there are some people will have visual double vision, trigeminal neuralgia; 2, if the arteriovenous fistula occurs in other parts, can occur brain hemorrhage, bleeding after the headache, hemiparesis, and even coma, can also appear seizures, which is commonly known as sheep epilepsy, we people. There are also some arteriovenous fistulas with symptoms of blood theft, limb weakness, dizziness, etc.