Infection of the eye by herpes simplex virus (HSV) is a leading cause of corneal blindness in the United States and other countries. The infection can lead to corneal scarring and neovascularization, permanent endothelial dysfunction and corneal edema, secondary glaucoma, and cataract. Despite the availability of topical antiviral agents that are highly active against HSV keratitis, there is still no known effective method for reducing the frequency of recurrence or severity of stromal keratitis and iridocyclitis. In addition, the prognosis is poor for recovery of good vision following penetrating keratoplasty for actively inflamed or highly vascularized herpetic corneas.