The cases of volume process in the sphenoid sinus engaging the retrobulbar segment of the orbit and scull base are rare and require interdisciplinary management [2,5,6,8]. In the following article we would like to present a patient with progressive reduction of the visus and causing blindness for 2 weeks. The patient came in our clinic for surgical treatment. The preoperative CT and MRT examinations describe mucocele in the left sphenoid sinus with invasion of the left optical nerve canal and the skull base. The left sphenoid sinus was opened paraseptally through the natural ostium. The intraoperative diagnosis was mucocele which was sucked and the natural ostium was enlarged for better drainage.