Initial funduscopic exam showed evidence of CRAO. Work-up for stroke was unremarkable. MRI orbits showed edema and contrast enhancement of the retrobulbar left optic nerve. Coronal DWI showed findings consistent with acute optic nerve infarction. He was treated with pulse-dose methylprednisolone with improvement in eye pain but no visual recovery. The diagnosis of ocular VZV in this patient was challenging for several reasons. Initial exam showed findings of CRAO without external signs of herpes zoster ophthalmicus. However, his age and progressive symptoms prompted evaluation for optic neuritis, with addition of coronal DWI after MRI findings suggested PION. Notably, initial cerebrospinal fluid analysis revealed normal protein, absent pleocytosis, and negative VZV PCR. The diagnosis of VZV retinitis was not made until signs of retinal necrosis emerged on funduscopic examination. VZV has been reported to cause both optic neuritis and PION, although no studies to date have demonstrated MRI evidence of optic nerve infarction associated with VZV.
Follow-up fundoscopic examination revealed new findings concerning for acute retinal necrosis, now involving the right eye. Vitreous fluid was positive for VZV by polymerase chain reaction (PCR). He was subsequently treated with systemic and intravitreal antivirals.