Herpes zoster in neuro-ophthalmology: a practical approach

Herpes Zoster (HZ) or shingles is the reactivation of the Varicella Zoster Virus (VZV), usually along a single sensory nerve, but can affect both sensory and motor cranial nerves. Major risk factors for HZ include immunosuppressed status and age older than 60 years. In the United States, the lifetime risk of HZ is approximately 30%. Worldwide, the median incidence of HZ is 4-4.5 per 1000 person-years across the Americas, Eurasia, and Australia. HZ ophthalmicus, occurring in 10-20% of patients, is an ophthalmic emergency characterized by VZV reactivation along the V₁ branch of the trigeminal nerve. Approximately half of this patient subgroup will go on to develop ocular manifestations, requiring prompt diagnosis and management. While anterior segment complications are more common, neuro-ophthalmic manifestations are rarer and can also occur outside the context of overt HZ ophthalmicus. Neuro-ophthalmic manifestations include optic neuropathy, acute retinal necrosis or progressive outer retinal necrosis, cranial neuropathy (isolated or multiple), orbitopathy, and CNS manifestations. Although typically a clinical diagnosis, diagnosis may be aided by neuroimaging and laboratory (e.g., PCR and serology) studies. Early antiviral therapy is indicated as soon as a presumptive diagnosis of VZV is made and the role of corticosteroids remains debated. Generally, there is wide variation of prognosis with neuro-ophthalmic involvement. Vaccine-mediated prevention is recommended. In this review, we summarize neuro-ophthalmic manifestations of VZV.