Infectious keratitis after laser vision correction: Incidence and risk factors.

PURPOSE To describe the incidence and risk factors associated with microbial keratitis in a large population of laser vision correction (LVC) patients. SETTING Optical Express centers, Glasgow, United Kingdom. DESIGN Retrospective case series. METHODS Records were searched to identify all cases of presumed microbial keratitis after LVC between January 1, 2008, and April 1, 2015. Consecutive patients having primary or enhancement LVC during that time served as controls. Data on preoperative age, sex, refraction, procedure, and surgery specifics were collected. A multivariate Cox proportional hazards model was used, and hazard ratios were calculated. RESULTS Definite or probable microbial keratitis occurred in 26 of 564 165 eyes after laser in situ keratomileusis (LASIK) and in 11 of 81 792 eyes after photorefractive keratectomy (PRK) during the study period, for an overall incidence of 0.0046% (1 case per 21 697 procedures) after LASIK and 0.0013% (1 case per 7434 procedures) after PRK. A multivariate analysis found that those having PRK had a significantly higher incidence of microbial keratitis than those having LASIK (hazard ratio, 2.92; 95% confidence interval, 1.42-6.00; P = .004). No other analyzed factors were significant. CONCLUSION Although the incidence of infectious keratitis was higher after PRK, the overall risk after any LVC procedure was very low.