Herpes zoster ophthalmicus ( HZO ) and also known as ophthalmic zoster is a disease characterised by reactivation of dormant varicella zoster virus residing within the ophthalmic nerve (the first division of the trigeminal nerve ).  :380  This condition is an important subtype of shingles , representing 15% of all cases.  Herpes zoster ophthalmicus is transmitted via direct contact or droplets. Varicella zoster virus is a DNA virus which produces acidophilic intranuclear inclusion bodies. The virus is neurotrophic in nature.
Herpes zoster ophthalmicus is an infection of the eye caused by varicella zoster virus. Herpes zoster ophthalmicus is the ocular involvement of an overall infection termed herpes zoster, commonly called shingles. Varicella zoster is the same virus that causes chicken pox. Once people are infected with this virus, usually by chicken pox as a child, it remains within the body in a dormant stage in the sensory ganglion (nerve roots). It is estimated that 95% of all adults harbor this virus and are therefore at risk for shingles. The risk of obtaining a herpes zoster infection during one’s lifetime is estimated at 10-20%. Estimates are that in the . alone each year there are one million cases of herpes zoster.
Zostavax vaccination is available (unsubsidised) for protection against shingles. A 2012 meta-analysis showed that older adults who had received the zoster vaccine had a 50% reduced incidence of shingles compared with those who had a placebo vaccination. 16 The vaccine was most effective in people aged 60 – 69 years (64% reduced incidence of shingles). 16 A related meta-analysis was inconclusive as to whether zoster vaccination prevents post-herpetic neuralgia in patients who get shingles despite vaccination. 17