Dry eye after LASIK for myopia: Incidence and risk factors

PURPOSE. Patients frequently experience dry eye symptoms after laser-assisted in situ keratomileusis (LASIK). The purpose of this study was to determine the incidence and risk factors of dry eye after myopic LASIK. METHODS. In this retrospective case series 190 eyes that underwent LASIK were examined for a dry eye syndrome. All patents were asymptomatic for dry eyes before surgery. Assessments included subjective complaints of dry eye, tear break-up time (TBUT), corneal staining, corneal sensitivity test, and Schirmer I test. All values were compared before and at 1 week and 1.3 and 6 months after surgery. RESULTS. For the 190 eyes, chronic dry eye persisting 6 months or more after LASIK was diagnosed in 20 percent of the eyes. Mean patient age was 31 8 years. The risk for chronic dry eye was significantly associated with higher attempted refractive correction, greater ablation depth, and female sex (p=0.001). Subjective score for dryness was increased after LASIK. The greatest change from preoperative levels for all parameters was noted at 1 week. There were obvious decreases in TBUT and Schirmer value at 1, 3, and 6 months postoperatively relative to preoperative level (p < 0.05). The Schirmer I test result was higher at 1 day but without statistical significance (p > 0.05), but lower at 1 week and 3 and 6 months (p < 0.05) after LASIK. Corneal sensitivity was decreased at 1 month and 3 months, and returned to the preoperative level at 6 months after LASIK. There was a statistically significant effect of age, sex, and mean spherical equivalent refraction on corneal sensitivity (P < 0.001). CONCLUSIONS. Patients undergoing LASIK for myopia develop dry eye with compromised tear function at least 6 months after surgery. Women and patients requiring higher refractive correction have an increased risk for developing dry eye.