Optic neuritis in herpes zoster ophthalmicus.

BACKGROUND Optic neuritis in herpes zoster ophthalmicus (HZO) has been reported rarely. We report two cases of HZO optic neuritis with detailed magnetic resonance imaging study and treatment responses. CASES One patient presented with anterior optic nerve involvement, and the second presented with retrobulbar optic neuritis. Contrast enhanced T(1)-weighted images were obtained in these 2 patients. Intravenous acyclovir and oral prednisolone were given simultaneously. OBSERVATIONS Magnetic resonance imaging revealed peripheral enhancement of the optic nerve sheath complex on T(1)-weighted scan. Both patients recovered their vision within 3 months following the start of treatment. CONCLUSIONS Magnetic resonance imaging is helpful for the diagnosis of HZO optic neuritis. Systemic acyclovir and steroid are effective in the treatment of HZO optic neuritis.