Purpose: To determine the surgical outcomes of therapeutic penetrating keratoplasty (PKP) and its role in the management of microbial keratitis.
Design: Interventional case series.
Methods: We retrospectively performed a chart review of the hospital records of all 151 patients undergoing therapeutic PKP for culture-proven microbial keratitis at the National Taiwan University Hospital during a 14 year-period (1987-2001). Patients were divided into three categories: (1) bacterial keratitis; (2) fungal keratitis; and (3) acanthamoebic keratitis. Each of the following criteria was evaluated: (1) graft clarity 1 month and 1 year postoperatively; (2) cure of the disease; and (3) anatomical success rate.
Results: A total of 108 therapeutic PKP met the criteria. Therapeutic PKP eradicated the infection in 37/41 of patients with bacterial keratitis, 36/52 of patients with fungal keratitis, and 13/15 of patients with acanthamoebic keratitis. 22/32 of grafts of bacterial keratitis, 20/39 of fungal keratitis, and 11/14 of acanthamoebic keratitis remained clear at 1 year postoperatively. A higher percentage of graft clarity at 1 year postoperatively was achieved in all three categories when grafts were 8.5 mm or less compared with larger grafts. All five patients with secondary endophthalmitis observed at the time of therapeutic PKP experienced a progression of infection despite aggressive surgical treatment, and had to be enucleated.
Conclusions: Therapeutic PKP is valuable in the management of microbial keratitis that is unresponsive to medical therapy. A higher percentage of clear graft was found when grafts were smaller in all three categories. Surgical results are worse for patients with fungal keratitis, regardless of graft clarity, anatomical success, or infection eradication rate.