Keratitis development following laser vision correction
There appears to be a high incidence of infectious keratitis after photorefractive keratectomy (PRK) in patients with laser vision correction (LVC), although the overall risk after any LVC procedure is very low, according to a study.
Researchers searched records to identify all cases of suspected microbial keratitis after LVC over a 7-year period (2008 to 2015). Consecutive patients who had primary or enhancement LVC during the same period were also included as controls. Information regarding preoperative age, sex, refraction, procedure and surgery specifics were obtained and analysed.
During the study period, definite or probable microbial keratitis developed in 26 of 564,165 eyes after laser in situ keratomileusis (LASIK) and in 11 of 81,792 eyes after PRK. The overall incidence was 0.0046 percent (1 case per 21,697 procedures) after LASIK and 0.0013 percent (1 case per 7,434 procedures) after PRK.
A multivariate Cox proportional hazards analysis found the incidence of microbial keratitis to be higher in the group of patients who underwent PRK than in the group of those who underwent LASIK (hazard ratio, 2.92; 95 percent CI, 1.42 to 6.00; p=0.004). No other analysed factors were significant.
Commonly performed to correct refractive errors, LASIK offers many benefits over PRK, including reduced time to visual rehabilitation, decreased stromal scarring, less postoperative pain, minimal regression and the ability to treat a greater range of refractive disorders. LASIK preserves the integrity of Bowman membrane and the overlying epithelium compared with other refractive procedures, and this is said to reduce the risk of microbial keratitis. [J Cataract Refract Surg 2011;37:1343–1350]
Infectious keratitis has become an increasingly recognized sight-threatening complication of refractive surgery. It presents with inflammation in the corneal interface, which can mimic diffuse lamellar keratitis (DLK). DLK typically develops within the first few days after refractive surgery, unless there is postoperative ocular trauma. Whereas DLK often presents with a diffuse appearance, infectious keratitis has a more focal area of infiltration. So any focal infiltrate surrounded by inflammation following LASIK should be considered infectious until proven otherwise. [J Cataract Refract Surg 2003;29:2007–2012; Cornea 2004;23:680–688]