Optic canal syndrome due to posterior ethmoid sinus mucocele. Case report.

A case of mucocele of the posterior ethmoid sinus presenting as unilateral blindness without pain, proptosis, or diplopia is reported. Computerized tomography (CT) demonstrated the precise anatomical relationship of the mucocele to the optic nerve inside the optic canal. It is proposed to use the term "optic canal syndrome" for patients with such clinical and CT presentation. Combined transcranial excision and transnasal drainage resulted in dramatic recovery of vision.