Herpes simplex keratitis is a common corneal epithelial infection in humans and felines. My answer will address treatment of HSV-1 in humans and not feline herpesvirus (FHV). The best treatment for herpes simplex keratitis is topical application of the antiviral ganciclovir in the form of an ophthalmic gel. Alternative treatments include trifluridine solution and vidarabine ointment, but these are more likely to be cytotoxic to the epithelium than the ganciclovir.