Antiviral medications and corneal wound healing

Masked controlled rabbit studies were done to determine the toxic effects on corneal wound healing of the antiviral ointments 0.5% idoxuridine, 3% Ara A, and 3% acyclovir, and the antiviral drops 0.1% idoxuridine, 3% Ara AMP, and 1% trifluridine. Ara A, acyclovir, trifluridine and idoxuridine drops had no significant effects on the rate of closure of epithelial wounds. Idoxuridine ointment given 5 times a day significantly retarded the rate of epithelial wound closure, but not when given 4 times a day. Only Ara AMP caused a retardation of epithelial healing and an actual increase in the defect after 4 days of treatment. Histopathologically all drugs, except acyclovir, showed a toxic effect on the regenerating epithelium. All drugs, except acyclovir, showed retarded stromal wound healing with reduced bursting strength and collagen content. Ara AMP had increased bursting strength and collagen content possibly because of greater inflammation. Acyclovir, in comparison to all the other medications studied, appeared to have minimal to no toxic effects on experimental epithelial and stromal wound healing, and on this basis is the agent of choice for use in herpes simplex stromal keratitis with ulceration and as a prophylactic agent for long-term use after penetrating keratoplasty.