Duration of contact lens removal before myopic refractive surgery

Purpose: To compare refractive surgery outcomes in patients with different periods without contact lenses prior laser surgery. Materials and methods: Patients included in this study underwent myopic keratorefractive laser surgery between January 2005 and December 2014. Patients were divided into three groups based on the duration of time passed free of soft contact lens wearing prior to final preoperative evaluation and surgery (<24 h, 1–3 days or >3 days). Spectacle wearers served as a control group. Postoperative safety index, efficacy index and % of eyes within 0.5 D of the four groups were compared. A general linear model was used to compare main outcomes while adjusting for age, gender, preoperative measurements, and procedure type (LASIK vs PRK). Results: Overall, 19,747 eyes were included. Soft contact lenses were worn by 42.3% (<24 h: 4.8%, 1–3 days: 18.5% and >3 days: 19.0%) and spectacles by 57.7% prior to surgery. In the PRK group, after adjusting for differences in baseline variables, the <24-h group had a significantly lower efficacy index than all the other groups. There were no significant differences between groups in terms of % eyes within ±0.5 D of intended correction (p = 0.55) or safety index (0.20). In the LASIK group, after adjusting for differences in baseline variables, there were no significant differences between groups in all primary outcomes. Conclusion: Soft contact lenses should be removed at least 24 h prior to final preoperative evaluation and refractive surgery, especially for patients undergoing PRK.