how do I treat corneal stromal disease secondary to feline herpesvirus-1 keratitis?

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Feline herpesvirus-1 (FHV-1) corneal stromal disease is managed with topical antiviral therapy as the foundation, with multimodal escalation for progressive or melting disease. All antiviral drugs used in cats are off-label, and success in treating ocular herpesvirus in humans does not translate directly to FHV-1. 4 Topical antivirals are the primary treatment for FHV-1 stromal keratitis. Trifluridine (trifluorothymidine) is a pyrimidine analog that inhibits viral DNA polymerase and achieves therapeutic stromal concentrations through good corneal epithelial penetration. Its main drawbacks are the need for frequent administration and stinging on application, both of which can limit compliance in cats. 4 Ganciclovir is substantially more efficacious against FHV-1 in vitro than acyclovir or cidofovir and is available as a 0.15% ophthalmic gel; it can also be compounded as a 0.5% solution with the addition of interferon alpha-2B. 4 Acyclovir is not the topical antiviral of choice due to poor efficacy against FHV-1. 4 Valacyclovir is contraindicated in cats — it is toxic and caused early termination of a clinical trial for humane reasons. 24 Systemic antiviral therapy with famciclovir is supported for FHV-1 keratitis. Orally administered famciclovir has resulted in improved clinical scores and reduced viral load in naturally infected cats. 2 The veterinary literature does not specify an exact dose in the provided sources, but famciclovir is the systemic antiviral of choice given the toxicity profile of alternatives. When FHV-1 stromal disease is complicated by secondary bacterial infection and keratomalacia (corneal melting), multimodal therapy is required. Progressive infectious keratitis warrants a combination of topical antibiotics, topical anti-collagenolytics, systemic antibiotics, systemic analgesics, and consideration of surgical stabilization techniques. 1 Photoactivated chromophore for keratitis–corneal cross-linking (PACK-CXL) is an established adjunctive thera