Optic Neuritis in Herpes Zoster Ophthalmicus: A Rare Manifestation of a Common Malady

Abstract

Herpes zoster optic neuropathy (HZON) is a rare manifestation of herpes zoster ophthalmicus (HZO). It is a potential- ly blinding condition. We report a case of an immunocompetent patient with HZON following keratouveitis during the course of treatment. A 33-year-old gentleman presented with left eye (LE) worsening of visual acuity (6/9 reduced to 6/24) despite on treatment for HZO keratouveitis. It was associated with pain on ocular movement and central scotoma. He was on systemic acyclovir and topical corticosteroids prior to current complaint. Fundoscopy showed left optic disc swelling with impaired optic nerve functions. Diagnosis of left optic neuritis secondary to HZO was es- tablished in view of close temporal relationship with occurrence of cutaneous herpes zoster. Systemic corticosteroids was commenced. The patient had obtained good visual outcome at two months. Early referral for ophthalmology assessment is crucial to establish diagnosis of HZON and prompt initiation of treatment may preserve vision.