The varicella-zoster virus often causes chicken pox. After chicken pox, this virus remains dormant in the nerve system. But if the virus reactivates, it spreads quickly and causes shingles, fever or nerve inflammations. This virus may also cause corneal infection - herpes zoster.
If the varicella-zoster virus spreads to the eye, it causes corneal lesions. If the infection is severe, or left untreated, the virus may damage cornea cells and cause corneal inflammation. This may also damage corneal sensitivity.
The following factors may pose higher risks: old age or weaker immune system. But the following circumstances may also make the virus reactivates: AIDS, chemotherapy, cancer, or emotional stress.