Carotid cavernous fistulas（CCF）are abnormal vascular communications between the carotid artery and cavernous sinus. We report a case of a patient previously diagnosed with bilateral openangle glaucoma that presented to the emergency department with a 6-month history of redness in the right eye. Glaucoma’s therapy optimization was proceeded upon a right intraocular pressure elevation（IOP）of 32 mmHg. One month later, he presented with proptosis, chemosis, and ophthalmoplegia in the right eye, leading to the diagnosis of ipsilateral dural CCF. These fistulas can present with subtle and progressive symptoms, requiring a high degree of suspicion. Embolization treatment, when indicated, is effective in rapidly reversing the ocular manifestations, including IOP elevation.