55-year-old male with rapidly progressive right eye proptosis, chemosis, visual loss and orbital compartment syndrome due to a spontaneous Barrow type B indirect caroticocavernous fistula (shunt between meningohypophyseal trunk, an intracavernous branch of the internal carotid artery, and cavernous sinus). The patient initially was treated with antibiotics and steroids with no response. CTA and MRI findings suggested a caroticocavernous fistula. The patient underwent emergent lateral canthotomy with cantholysis and subsequent transvenous embolization of the caroticocavernous fistula Onyx-18 with symptomatic relief and residual blepharoptosis 9 months after treatment. The patient is planned for 9 mm right internal levator advancement for the treatment of blepharoptosis in the future.