Microbial Keratitis and Endophthalmitis After the Boston Type 1 Keratoprosthesis

Purpose: To determine the incidence, ocular surface disease associations, microbiological profile, and clinical course of postoperative infections after implantation of the Boston type 1 keratoprosthesis (KPro-1). Methods: A retrospective chart review was conducted of all cases of the KPro-1 performed at a tertiary eye care center between January 1, 2008, and December 31, 2014. Results: Seventy-five KPro-1 procedures were included in the analysis. Postoperative infections occurred in 13 eyes (17.3%) with an incidence of 0.064 cases per eye-year. The Kaplan-Meier probability of an infection-free graft was 0.96, 0.90, 0.88, 0.87, and 0.86 at years 1 through 5, respectively. The rate of infections was greater in eyes with ocular surface disease (26.3% vs. 8.1%, P = 0.06), especially in those with a history of chemical or thermal injury or herpes zoster keratopathy (P = 0.001). There were 8 cases (10.7%) of microbial keratitis due to either fungi (5 cases) or bacteria (3 cases). There were 7 cases (9.3%) of endophthalmitis due to bacteria (5 cases) or intraocular extension of fungal keratitis (2 cases). The incidence of microbial keratitis and endophthalmitis was 0.034 and 0.03 cases per eye-year, respectively. Therapeutic management of the infected eyes required graft and device removal in 7 eyes (53.8%). After completion of microbiologic treatment, 7 eyes (53.8%) had lost more than 2 lines of the best-corrected preinfection visual acuity, including 5 eyes with endophthalmitis that had hand motion vision or worse. Conclusions: Postoperative infections are a serious issue that compromises device retention and visual outcomes after keratoprosthesis implantation.