Recovery from long-term severe visual impairment due to mucocele in the Onodi cell

The Onodi cell is a pneumatized posterior ethmoid cell that lies on the sphenoid sinus and is closely related to the optic canal. A rare case of a patient who was relieved from longterm severe visual impairment caused by mucocele in the Onodi cell is presented herein. An 80-year-old man was referred to the hospital by an ophthalmologist with a complaint of blurred vision in the right eye for a couple of months. A computed tomography scan demonstrated a cystic lesion occupying the right posterior ethmoid sinus, which suggested the Onodi cell. In addition, a bone defect of the optic canal was present. Ophthalmologic examination showed no papilledema. However, severe visual impairment and narrowing of the visual field in the right eye were noted. Surgical treatment using the endoscopic endonasal approach was performed under general anesthesia. Purulent discharge oozed out when the cystic lesion in the right posterior ethmoid sinus was opened. His visual impairment and severe visual field contraction gradually improved after surgery. In this case, the patient’s severe visual impairment improved although a couple of months had passed before treatment. Preoperative fundus examination showed no optic nerve atrophy or inflammatory optic neuropathy in the right eye, counting fingers and visual acuity was considered to have improved.