The herpes zoster or shingles infection is caused by the varicella-zoster virus, the virus which causes chickenpox. When the virus first manifests as chickenpox, usually during childhood, it remains inactive within the nerve cells of the central nervous system; but it can recur at a later time in the patient's life and infect some part of the body causing a blistering rash (shingles), fever, painful inflammations of affected nerve fibers and a general lethargy.
But varicella-zoster can travel to the head and neck, involve an eye, part of the nose, cheek and forehead. It is estimated that the cornea will be affected in about 40% of those with shingles in these areas.
Medication usually consists of oral anti-viral treatment to reduce the risk of the virus infecting cells deep within the tissue and inflaming and scarring the cornea. The disease also can cause decreased corneal sensitivity, which results in foreign matter in the eye not being as keenly felt as before. For many, this decreased sensitivity will be permanent.
Once exposed to the varicella-zoster virus, no one is immune from shingles, but clinical studies have established two risk factors for the disease:
There is a much greater chance of people over 80 contracting shingles than those between the ages of 20 and 40. Unlike the herpes simplex 1 virus, varicella-zoster usually does not break out more than once in adults with normally functioning immune systems.
Corneal problems can arise only months after the disappearance of shingles, and for this reason it is particularly important for those who have had facial shingles to have eye examinations as soon after the disease as possible.