Herpes Zoster Ophthalmicus (HZO) refers to a viral infection that causes a painful rash and blisters around the eye. This condition is caused by the same virus that causes chickenpox, the varicella-zoster virus. There are several synonyms used for HZO, including shingles of the eye, ophthalmic shingles, or ocular herpes zoster. The symptoms of HZO include redness, eye pain, and sensitivity to light, and may be accompanied by fever and fatigue. The condition is usually treated with antiviral medication and eye drops prescribed by a doctor. If left untreated, HZO can lead to complications such as loss of vision or even blindness.