Purpose
To determine the incidence of microbial keratitis 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 2010 at 25 Optical Express surgery centers in the UK 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
There were 186,019 eyes of 95,523 patients treated during the study time period of which 54% were females, 91% underwent LASIK and 69% of LASIK cases had a femtosecond flap. Within this population, 16 patients had culture proven or a strong clinical suspicion of microbial keratitis (collectively called the ‘infection’ cohort) which was diagnosed between 3 days and 2.5 months after surgery (incidence 0.017%, or 1:5,970). The average age between the control and infection cohort was similar (mean 37.0 ± 11.9 and 37.1 ± 10.9 years, respectively). However a higher incidence of microbial keratitis was observed in males compared to females (0.023% vs 0.012%, respectively) and in patients with preop myopia compared to hyperopia (0.018% vs 0.010%, respectively). In addition, the incidence of microbial keratitis was higher after PRK than LASIK (0.032% vs 0.015%, respectively) and for LASIK cases that underwent a mechanical keratome compared to a femtosecond laser created flap (0.025% vs 0.013%).
Conclusions
The incidence of microbial keratitis after modern laser vision correction in a large refractive surgery population is very low (1:5,970). This is similar or lower than previous reports (1:1,000 to 1:5,000). While there were relatively few microbial cases, several associations were observed and include male gender (1:4,429), preoperative myopia (1:5,501), undergoing a surface ablation procedure (1:3,161) and the use of a mechanical keratome for the LASIK flap creation (1:3,938).
Keywords: 680 refractive surgery: complications •
573 keratitis •
678 refractive surgery