Herpes zoster, which is also known as shingles, is the same virus that causes chicken pox in children. After a person has chicken pox, the virus may remain dormant in certain nerves in the body. Later in life the virus may reactivate and cause herpes zoster dermatitis (shingles). The reactivation may be associated with other illnesses or conditions that impair the immune system. While most of us had chicken pox as children, the prevalence of ocular herpes zoster as an active disease is less than one percent of the population.
Once re-activated, the virus usually affects areas of skin on just one side of the body. When herpes zoster is located in the nerve branch that supplies the eyes, the forehead, nose and eyelids may also be affected (called herpes zoster ophthalmicus or HZO). Herpes zoster can cause a wide range of problems affecting the skin and the eye. HZO may lead to redness, light sensitivity, swollen eyelids, dry eye, blurred vision, infection of the cornea, inflammation of the optic nerve, inflammation of the iris, glaucoma and formation of cataracts.
Herpes zoster can also be extremely painful and is usually treated with anti-viral and anti-inflammatory medications; treatment may take several months. Lubricating eyedrops or antibiotic eye drops may also be prescribed during an outbreak. Although there currently is no cure for this virus, early diagnosis and treatment are important to minimize symptoms and reduce the risks of eye-related problems.
Childhood immunization for chicken pox became commonplace in the US in the late 1990’s. Since HZO occurs only in patients who have had chicken pox and not those who were immunized, the HZO incidence rate should begin to fall in the next few decades. However, five to ten percent of patients who have had chicken pox will have shingles in their lifetime, and ten to twenty percent of those patients will encounter HZO.