Objective: To assess the efficacy of prophylactic topical antiviral therapy after penetrating keratoplasty for herpes simplex keratitis in the postoperative period and during the treatment of allograft rejection episodes with topical steroids. We used these data to make predictions of the sample size required to perform a prospective study of prophylactic oral acyclovir in the postoperative period.
Design: Retrospective review.
Setting: A university referral cornea service.
Patients: One hundred thirty-two consecutive penetrating keratoplasties for herpes simplex keratitis in 119 eyes of 118 patients. Only four grafts were performed in actively inflamed eyes.
Interventions: Sixty-six (52%) of the grafts performed in quiescent eyes received prophylactic postoperative topical antiviral treatment, three (2%) received oral acyclovir, and 59 (46%) received no antiviral therapy. The mean (+/- SD) duration of antiviral therapy was 12.8 +/- 22.5 months.
Main outcome measures: Herpetic recurrence, allograft rejection episodes, and graft failure.
Results: Multivariate analysis showed that early antiviral use was associated with a decreased risk of herpes simplex keratitis recurrence (relative risk [RR] = 0.44; 95% confidence interval [CI], 0.21 to 0.94; P = .007) and allograft rejection (RR = 0.43; 95% CI, 0.25 to 0.75; P = .002). Graft failure was associated with herpetic recurrence within the first year (RR = 2.25; 95% CI, 1.09 to 4.64; P = .001) and allograft rejection episodes (RR = 2.56; 95% CI, 1.20 to 5.26; P = .003). Using these data, a prospective trial of postoperative oral acyclovir would require between 59 and 112 patients per group.
Conclusions: Postoperative prophylactic antiviral treatment is associated with decreased rates of herpes simplex viral keratitis recurrence and allograft rejection. Early recurrence is associated with an increased risk of graft failure. A prospective study of postoperative oral acyclovir would require a multicentered approach.