Latanoprost increases the severity and recurrence of herpetic keratitis in the rabbit

To determine whether topically applied latanoprost increases the severity of acute herpes simplex keratitis, the rate of recurrence of herpes keratitis, or both, in the rabbit.

To determine the effect on severity of acute herpetic keratitis, the corneas of New Zealand white rabbits were infected with either the less-corticosteroid-sensitive McKrae strain or the corticosteroid-sensitive F(MP)E strain of herpes simplex virus type 1. Rabbits were randomly assigned to twice-a-day treatment with latanoprost 0.005%, dexamethasone sodium phosphate 0.1%, or balanced saline solution within 3 days of infection and evaluated daily for up to 13 days after infection. The severity of keratitis was graded in a masked manner. To determine the effect on recurrences of herpetic keratitis, animals infected with McKrae strain herpes simplex virus type 1 that survived to day 32 after infection were randomized to treatment with latanoprost 0.005% or balanced saline solution and evaluated for the presence of corneal lesions from postinfection day 32 to day 47.

In the severity studies, treatment of F(MP)E-infected corneas with latanoprost or dexamethasone significantly worsened herpetic keratitis; by postinfection day 5, F(MP)E-infected eyes treated with dexamethasone or latanoprost demonstrated significantly higher severity scores than the eyes treated with balanced saline solution (P = .0001 and .008, respectively). Scores of McKrae-infected corneas treated with latanoprost or dexamethasone were not significantly different from scores of balanced saline solution-treated corneas. In the recurrence study, treatment with latanoprost significantly increased the appearance of clinical recurrences in McKrae-infected eyes, compared with balanced saline solution treatment (P = .0064).

Latanoprost may worsen acute herpetic keratitis in the rabbit eye and increase the risk of recurrences in latently infected animals.