Keratitis is an inflammation of the cornea — the clear, dome-shaped tissue on the front of your eye that covers the pupil and iris. Keratitis may or may not be associated with an infection. Noninfectious keratitis can be caused by a relatively minor injury, by wearing your contact lenses too long or by a foreign body in the eye. Infectious keratitis can be caused by bacteria, viruses, fungi and parasites.
HSV (Herpes Simplex Virus) keratitis is an infection of the cornea—the clear dome that covers the colored part of the eye—that is caused by HSV. The infection usually heals without damaging the eye, but more severe infections can lead to scarring of the cornea or blindness. HSV keratitis is a major cause of blindness worldwide. HSV-1, which is the type of HSV that also causes cold sores on the mouth, is the most common cause of corneal infections.
HSV is only found in humans and is spread through direct contact with someone who is infected with the virus. Most HSV keratitis infections happen after another part of the body—most commonly the mouth —has already been infected by HSV. HSV keratitis is often the result of a “flare up” (reactivation) of the earlier infection.