Microsurgical decompression of the optic nerve was performed in 22 patients with traumatic optic nerve injury through a transfrontal intradural approach. When significant improvement is defined as an improvement of the visual acuity of 0.1 or more, 11 patients (50%) showed significant improvement and 7 patients (32%) showed non-significant improvement. Four patients who had been blind preoperatively, did not show any improvement. In cases with a preoperative visual acuity of 0.01 or more, significant improvement was obtained in 80% of the patients, and when the preoperative visual acuity was not nill but less than 0.01, 38% of patients showed significant improvement. We conclude that a transfrontal intradural microsurgical decompression is indicated, when the preoperative visual acuity is 0.01 or more and the time lag is less than 14 days after the injury.