Until recently, acute optic neuritis, even when clinically typical, could not be diagnosed with certainty, because considerable difficulty was encountered in the accurate demonstration of retrobulbar lesions. The advent of computerized tomography has changed this situation. The OCT scan can demonstrate inflammatory conditions as a focal density. But only a few authors have commented on the OCT scans of acute optic neuritis. The author demonstrated a series of OCT scans of the recurrent type of acute optic neuritis of a 30-year-old male patient. The finding was characterized by a unilateral remarkable enlargement of the whole portion of the optic nerve, and the enlarged optic nerve changed in size corresponding with the clinical signs during the course of the disease.