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.