There are two types of herpes viral infections of the eye. One, called herpes simplex keratitis, is caused by the herpes simplex 1 virus, HSV-1, the same virus that causes cold sores on the lips and mouth. The other, herpes zoster ophthalmicus, is caused by the varicella zoster virus that causes chickenpox and shingles. There are other members of this family of viruses that are not known to infect the eye; the most familiar is the one that causes genital herpes. The same antiviral drugs are used to treat all of them.
Herpes simplex keratitis and herpes zoster ophthalmicus have some symptoms in common:
1. Pain in and around only one eye.
2. Redness of the eye.
3. Swelling or cloudiness of the cornea.
The zoster infection is often distinguished by redness or rash on the eyelids and surrounding skin of the forehead and nose. The simplex infection typically includes:
1. A feeling of dirt or grit in the eye.
2. Excess tears.
3. Pain when looking at bright light.
Most adults in the U.S. carry at least one type of herpes virus in a latent, or dormant, state. Chickenpox was so common when I was a kid that parents deliberately exposed children to the germs at an early age (let's go play with that sick child from school!) to get it over with as soon as possible. Since chickenpox tends to be worse for adults than for children, this strategy made some sense. Unfortunately, the virus may live in our nerve fibers for the rest of our lives. Most of the time it causes no problems, but sometimes it multiplies and causes other problems. Shingles, with or without the eye infection, is a common outbreak of the chickenpox virus in older Americans. Doctors typically prescribe pills and/or eye drops to treat herpes eye infection. It is important to take the medication for as long as your doctor recommends, even if you feel better sooner, because the infection can recur.
Herpes simplex keratitis may cause corneal blindness if not treated promptly. An estimated 400,000 Americans have been affected, and the infection can recur in up to 50 percent of cases. Stromal keratitis is caused by spread of the infection into the deeper layers of the cornea and is more difficult to treat than herpes in the corneal epithelial cells. Corneal lesions are also possible. So as in the herpes zoster case, see your doctor as soon as you notice symptoms and follow the full course of medication.
Resources:
Amy L. Sutton, ed, “Eye Care Sourcebook”, Omnigraphics, 2008.
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.