This case features a 67-year-old woman with a month-long headache, diplopia, and left eye drooping, diagnosed with bilateral indirect carotico-cavernous fistula (Barrow Type D). Endovascular treatment via the femoral venous route successfully navigated to the cavernous sinus, resulting in complete resolution of eye redness and chemosis, with mild residual lateral rectus palsy. Dive into this case to explore the technical challenges and success of transvenous embolization for carotico-cavernous fistulas.