We performed an effective optic canal decompression in a patient with ethmoid and sphenoid fibrous dysplasia and visual impairment following minor head trauma. On admission, the patient's left visual acuity consisted only of light perception, and the left ophthalmic artery was not visible by angiography. A hematoma and fibrous dysplasia tissue in the sphenoid sinus were excised and the left optic canal was decompressed. The vision was markedly improved to an ability to count fingers in the following 2 weeks. The left ophthalmic artery was fully opacified in the postoperative angiogram.