Orbital Apex Syndrome Secondary to Herpes Zoster Ophthalmicus: A Literature Review and In-Depth Understanding.

Purpose: The aim of this study was to report our experience and to provide a comprehensive understanding of the onset and course of orbital apex syndrome secondary to herpes zoster ophthalmicus (HZO-OAS).

Methods: A retrospective study was conducted in Nice University Hospital and Antibes Hospital (France) between January 2020 and December 2023. All patients diagnosed with HZO-OAS with at least a 1-month follow-up were included.

Results: Eight patients with a mean age of 81 (73-90) years were included. Half of the patients had underlying immunosuppression. The mean time between the onset of the vesicular rash and the development of HZO-OAS was 10 (2-19) days. HZO-OAS occurred while all patients were already treated with oral valacyclovir. The mean initial best-corrected visual acuity (BCVA) was 20/1093. All patients had concomitant ocular involvement, i.e. keratitis, anterior uveitis or both. Seven (87.5%) patients had optic neuritis. All patients were treated with intravenous acyclovir at neuro-meningeal doses. Oral steroids were prescribed in 62.5% of patients with gradual tapering. The mean BCVA was 20/87 at 3 months. Almost all patients experienced a complete resolution of ophthalmoplegia and ptosis at 3 months. Residual mydriasis was observed in 37.5% of patients. We proposed a schematic diagram describing the course of HZO-OAS.

Conclusion: HZO-OAS is a rare but devastating complication occurring mainly in older and immunosuppressed patients despite treatment with oral antivirals. Early identification and treatment with intravenous acyclovir combined with steroids appear to be essential.