Herpes Zoster (Shingles)
This infection is a recurrence of the varicella-zoster virus, which is the same virus that causes chickenpox. After an initial episode of chickenpox (often during childhood), the virus remains inactive in the nerve cells of the central nervous system. In some people, the virus will reactivate at another time in their lives, usually when ill or stressed. When this happens, the virus travels down the nerve fibers and infects a part of the body, usually the trunk or face, producing a blistering rash (shingles), painful inflammation, and a general feeling of sluggishness.
When the virus affects the head and neck, it sometimes involves an eye, part of the nose, cheek, and forehead. In approximately 40 percent of those with shingles in these areas, the virus infects the cornea. Doctors will often prescribe oral anti-viral medication (pill) to reduce the risk of the virus infecting corneal cells. The disease may also cause decreased corneal sensitivity, meaning that foreign matter that gets into the eye is not felt. For many, this decreased sensitivity will be permanent.
Shingles can occur in anyone exposed to the varicella-zoster virus. There are, however two risk factors: advanced age and a weakened immune system. People over 80 years old have a five times greater chance of having shingles than adults under 40. Shingles does not typically occur more than once in adults with normal immune systems. You should be aware that corneal problems may begin months after shingles affecting the face have resolved. It is therefore important to have a follow-up eye exam.