Incidence and Factors Associated With Microbial Keratitis in Large Cohort of Consecutive Corneal Refractive Surgery Patients
Narrative Responses:
Purpose
To determine the incidence of microbial keratitis (MK) after modern LASIK and PRK procedures and to identify associated factors in a large consecutive refractive surgery population.
Methods
All primary LASIK and PRK treatments conducted between January 2009 and December 2011 at 25 Optical Express surgery centers in the UK (189,213 eyes of 96,622 patients) as well as all confirmed or presumed microbial keratitis cases that occurred in these patients were retrospectively reviewed. Demographic, preoperative and surgical factors as well as surgical technique were compared. All patients were prescribed a flouroquinolone eye drop to be used 4 times a day for one week (LASIK) or until complete epithelialization and bandage contact lens removal (PRK). Presumed microbial keratitis cases were cultured and treated with intense topical antibiotics.
Results
16 patients were diagnosed with MK between 3 days and 2.5 months after surgery (incidence 0.017%, or 1:5,970). The mean age between controls and infection cohort was similar (37.0 ± 11.9 and 37.1 ± 10.9 years, respectively). A higher incidence of MK was observed in males compared to females (0.023% vs 0.012%) and in patients with preop myopia compared to hyperopia (0.018% vs 0.010%). The incidence of MK was higher after PRK than LASIK (0.032% vs 0.015%) and for LASIK cases that underwent a mechanical keratome compared to a femtosecond laser created flap (0.025% vs 0.013%).
Conclusion
The incidence of microbial keratitis after LVC in a large refractive surgery population is low (1:5,970) and similar to previous reports (1:1,000 to 1:5,000). Associations include male gender (1:4,429), preoperative myopia (1:5,501), surface ablation procedure (1:3,161) and the use of a mechanical keratome for the LASIK flap creation (1:3,938).