Eye disease due to herpes simplex virus (HSV) is a leading cause of ocular morbidity and the number one infectious cause of unilateral corneal
blindness in the developed parts of the globe. Recurrent
keratitis can result in progressive corneal
scarring, thinning, and vascularization.
Antiviral agents employed against HSV have primarily been
nucleoside analogs. Early generation drugs included
idoxuridine, iododesoxycytidine,
vidarabine, and
trifluridine. While effective, they tended to have low bioavailability and measurable local cellular toxicity due to their nonselective mode of action.
Acyclovir 0.3%
ointment is a more selective agent, and had become a first-line topical
drug for acute HSV
keratitis in Europe and other places outside of the US.
Ganciclovir 0.15% gel is the most recently approved topical treatment for herpes
keratitis. Compared to
acyclovir 0.3%
ointment,
ganciclovir 0.15% gel has been shown to be better tolerated and no less effective in several Phase II and III trials. Additionally, topical
ganciclovir does not cause adverse systemic side effects and is therapeutic at lower concentrations. Based on safety, efficacy, and tolerability,
ganciclovir 0.15% gel should now be considered a front-line topical
drug in the treatment of dendritic
herpes simplex epithelial
keratitis. Topics of future investigation regarding other potential uses for
ganciclovir gel may include the prophylaxis of recurrent HSV epithelial
keratitis, treatment of other forms of ocular disease caused by herpesviruses and adenovirus, and
ganciclovir gel as an adjunct to antitumor
therapy.