Endophthalmitis after keratoprosthesis: incidence, bacterial causes, and risk factors.

OBJECTIVES To determine the rate of endophthalmitis in a group of patients with keratoprostheses and to analyze possible risk factors. METHODS A total of 108 patient eyes, operated on between 1990 and 2000 with double-plated keratoprostheses, were analyzed with regard to the surface flora, the incidence and cause of bacterial endophthalmitis or sterile vitreitis, the keratoprosthesis design, prophylactic antibiotics, concomitant immunosuppression, and preoperative diagnosis. RESULTS Surveillance cultures were obtained from 30 uninfected eyes. The flora was similar to that reported in the normal population and did not vary significantly with time. Thirteen cases of bacterial endophthalmitis occurred 2 to 46 months postoperatively in the patient population that had been followed up for 2 months to 17 years (average, 3 years 4 months). The incidence was 39% in 13 patients with Stevens-Johnson syndrome, 19% in 27 patients with ocular cicatricial pemphigoid, and 7% in 28 patients with ocular burns. Only 1 of the other 40 cases (consisting mostly of repeated graft failures in noncicatrizing conditions) developed endophthalmitis; this patient had a filtering bleb. All endophthalmitis pathogens were gram positive: Streptococcus pneumoniae, 23%; other streptococci, 39%; Staphylococcus aureus, 23%; and Staphylococcus epidermidis, 15%. CONCLUSIONS The most important risk factor for endophthalmitis after these keratoprostheses was found to be preoperative diagnosis. The rate of infection was very high in Stevens-Johnson syndrome and ocular cicatricial pemphigoid, moderate in chemical burns, and low in noncicatrizing corneal disease.