Clinical Trials of Topical Interferon Therapy of Ulcerative Viral Keratitis

An open trial suggested that monkey interferon had a therapeutic effect on ulcerative vaccinial keratitis in humans. A randomized, double-blind, placebo-controlled trial of either monkey interferon or drops of idoxuridine (given hourly by day and at 2-hr intervals by night for three days) suggested a therapeutic effect from idoxuridine but not from monkey interferon. Results of experiments with rabbits suggested that a daily application of human interferon (1.1 x 10⁷international units/ml) would be effective in the prevention of herpetic ulcers but might not affect established lesions. Preliminary results are encouraging in a placebo-controlled, randomized trial of human interferon given once daily for seven days for prevention of recrudescence of epithelial herpetic lesions after minimal wiping debridement with a cotton-tipped swab. The design of the trial is closely analogous to that of the experiments with rabbits and permits ethically acceptable, placebo-controlled trials of antiviral agents.