Combined Central Retinal Artery Occlusion, Central Retinal Vein Occlusion, and Anterior Ischemic Optic Neuropathy Following Herpes Zoster Ophthalmicus: A Case Report

Abstract

Aims: To describe an exceptionally rare and sight-threatening posterior segment complication of herpes zoster ophthalmicus (HZO), characterised by combined central retinal artery occlusion (CRAO), central retinal vein occlusion (CRVO), and anterior ischaemic optic neuropathy (AION) in an immunocompetent older patient. Presentation of Case: A 76-year-old man with coronary artery disease and chronic renal failure initially presented with right-sided HZO involving the forehead and upper eyelid. Baseline best-corrected visual acuity was 20/25 in both eyes, with normal intraocular pressure and no posterior segment abnormalities. Four days after the initiation of systemic valacyclovir, he developed sudden, profound visual loss in the right eye. Examination revealed no light perception, a relative afferent pupillary defect, anterior uveitis, optic disc oedema, diffuse retinal haemorrhages, venous dilatation, and whitening of the posterior pole. Fluorescein angiography demonstrated delayed arterial and venous filling, capillary non-perfusion, and optic disc hypofluorescence followed by late staining. Swept-source optical coherence tomography showed cystoid macular oedema and hyperreflective inner retinal layers. Systemic evaluation excluded giant cell arteritis, syphilis, human immunodeficiency virus infection, carotid disease, and other secondary causes. Discussion: The findings supported simultaneous CRAO, CRVO, and AION associated with recent HZO, without clinical evidence of acute retinal necrosis. The likely mechanism was varicella-zoster virus-related occlusive vasculopathy affecting the retinal and optic nerve head circulation. Conclusion: HZO can rarely induce catastrophic, multisite ocular vascular occlusion. Sudden visual loss during or shortly after HZO requires urgent multimodal retinal imaging, systemic evaluation, and multidisciplinary management.