Isolated optic neuritis with a concurrent abnormal trigeminal nucleus on imaging: case report of a rare complication of herpes zoster ophthalmicus.

Isolated ON is a rare ocular complication following HZO. An abnormal high signal of STNT on a T2 weighted image may be present, which may be a clue for VZV-associated complications, such as HZO-related ON, especially in cases lacking an obvious history of HZO or other concomitant ocular complications. Prompt treatment with both acyclovir and corticosteroids should be started. Restricted diffusion of the optic nerve may be a predictor for poor visual recovery.