International Multicenter Study on SMILE Surgery

Inclusion Criteria: * be accompanied by a parent or guardian who is able to give informed consent as demonstrated by signing a record of informed consent; * at baseline, be within the age range of 18 to 45 years old inclusive * normal corneal morphology with no corneal nebula or corneal macula, the range of preoperative K2 (the steep curvature of the 3mm area at the center of cornea) from 38.0 to 47.0 diopter * manifest spherical equivalent of -1.0 to -10.0 diopters (D) * cylindrical diopter no more than -5.0D * refractive diopter maintained stable for more than2 years * preoperative BCVA≥0.8, and the scotopic pupil diameter≥5.0mm when measured by WASCA analyzer (Carl Zeiss Meditec AG) * picked off soft contact lens for more than 2 weeks * picked off RGP for more than 1 month * preoperative corneal central thickness measured by Pentacam \>500μm, non-contact IOP\<21mmHg * be willing to comply with the clinical trial visit schedule as directed by the investigator. Exclusion Criteria: * any corneal diseases, corneal operations, eyes trauma or systemic diseases history; keratoconus or tendency of keratoconus * corneal macula and obvious pannus; current enrolment in another clinical trial/research project.