Microbial keratitis after penetrating keratoplasty

Purpose: To investigate the prevalence of microbial keratitis, predisposing risk factors, the spectrum of pathogens and the prognosis for graft surviv al and visual outcome in patients who developed microbial keratitis followi ng penetrating keratoplasty (PK). Material and methods: We reviewed 16 cases (15 patients) of microbial kerat itis after PK. In all cases, corneal scrapings were obtained and microbiolo gically analyzed. Efficacy of treatment was evaluated by anatomical (clarit y of graft) and visual recovery. Results: Principal indications for PK were pseudophakic bullous keratopathy (50%) and microbial keratitis in the previous graft (25%). Sixty-three per cent of infections occurred within 1 year of PK. Principal predisposing ri sk factors were suture-related problems (44%) and microbial keratitis in th e previous graft (25%). All of the scrapings were positive according to the microbiological evaluation with gram-positive cocci (64%), gram-positive r ods (12%), fungi (18%), and Acanthamoeba (6%). We found 1 case of polymicro bial infection. Best visual and anatomical results were observed in nonadva nced cases and/or these treated early. After medical and surgical treatment s, 8 patients (50%) had a clear graft and 10 patients (63%) had visual acui ty less than 20/200, Conclusion: Postoperative control of risk factors and early recognition of infectious complications may decrease the incidence of severe microbial ker atitis after PK.