Contributor: Gordon K. Klintworth
Herpes zoster ophthalmicus is a special type of  Herpes zoster characterized by the development of a vescicular rash in the dermatome innervated by the first division of the trigeminal nerve. This viral infection follows reactivation of varicella-zoster virus from foci of latent infection in the trigeminal ganglion. After several months of ocular herpes zoster infection a late, deep, localized episcleritis and scleritis may occur. Varicella-zoster virus can invade the retina and cause acute retinal necrosis.