Efficacy of low-dose and long-term oral acyclovir therapy after penetrating keratoplasty for herpes simplex heratitis

Purpose: To evaluate the efficacy of long-term and low-dose prophylactic or al acyclovir therapy in preventing the recurrence of herpetic infection and increasing graft survival in patients who undergo penetrating keratoplasty (PK) for herpes simplex keratitis (HSK). Patients and methods: Nineteen pa tients were included in the study, who underwent PK for herpes keratitis fr om July 1993 to November 1995, received oral acyclovir, and were followed a t least 12 months. Group I included 12 patients with corneal scarring witho ut perforation. These patients were free of inflammation for a mean of 4.1/-2.2 months preoperatively, and received oral acyclovir 400 mg/day postope ratively for one year. Seven patients (Group 2) who developed corneal perfo ration due to necrotizing keratitis were treated with tissue adhesives, the rapeutic contact lenses, and topical antiviral and oral acyclovir therapy f or the resolution of active inflammation followed by PK after a mean of 3.8 +/-2.1 months follow-up. They received oral acyclovir 400 mg/day postoperat ively for one year in addition to standard postoperative therapy. The contr ol group consisted of 16 patients (Groups 3 and 4) who underwent PK for her pes simplex keratitis and did not receive oral acyclovir. The indication fo r PK was corneal opacity and impaired visual acuity in It patients (Group 3 ) and corneal perforation in four (Group 4) Results: After an average of 25 months follow-up, there: was only one recurrence (8.3%) in Group I and two cases (28.6%) of herpetic recurrence in Group 2. Recurrence occurred at tw o months in one patient while he was taking oral acyclovir. Two of these re currences followed the withdrawal of oral acyclovir therapy after one year of therapy. In contrast, in control groups there were four cases of herpeti c recurrence (33.3%) in Group 3 and two (50%) in Group 4 after a mean of 30 .5 months postoperative follow-up. In the study groups, a rejection episode was seen in three patients (15.8%) which was successfully treated with med ical therapy. One patient from Group 2 developed bacterial keratitis which subsequently resulted in graft failure. All grafts remained clear in the ot her patients (94.7%) In the control groups, rejection developed in seven pa tients. Three rejection episodes were treated successfully, The other four developed graft failure in spite of intensive medical therapy. Conclusions: Our results suggest that postoperative oral acyclovir therapy is effective in preventing the recurrence of herpetic infection. However, the recurrenc e may develop after cessation of oral acyclovir therapy, especially in pati ents who underwent PK for corneal perforation due necrotizing HSK.