Which topical antiviral is commonly used for HSV keratitis in addition to or instead of trifluridine?

• A. Ganciclovir
• B. Trifluridine
• C. Acyclovir
• D. Foscarnet

Answer: (A)

Topical antivirals for HSV keratitis are designed to halt viral DNA synthesis in infected corneal cells. Ganciclovir, delivered as an ophthalmic gel, is activated inside HSV-infected cells by viral kinases and then inhibits viral DNA polymerase, stopping replication. This makes it a strong option to use alongside trifluridine or as an alternative when you need effective antiviral activity with good tolerability. Trifluridine is effective but tends to irritate the ocular surface and requires very frequent dosing, which can be hard on patients and increase toxicity risk. Ganciclovir generally offers a more favorable side effect profile on the cornea and provides reliable activity against HSV-1 and HSV-2, so it’s commonly chosen in practice. Foscarnet is typically reserved for acyclovir-resistant HSV infections and is not a first-line topical for routine HSV keratitis. Acyclovir can be used systemically for HSV infections, but its topical penetration and overall performance in keratitis are less favorable compared with ganciclovir.