A healthy 41-year-old women had acute retrobulbar optic neuritis with superior altitudinal hemianopia four weeks after cutaneous herpes zoster. Her visual acuity decreased to 0.04 OD, and mild iritis was noticed. However, ophthalmoscopic examination and fluorescein angiography disclosed no remarkable change. She had a low amplitude during flash visual-evoked potential testing with almost normal latency time in the acute stage. Corticosteroid therapy was administered, and her visual acuity and visual-field defect rapidly improved. Complete recovery, including the pattern-reversal visual-evoked potential results, was obtained.