The aim of this study is to further optimize the surgical input parameters for patients undergoing Small Incision Lenticule Extraction (SMILE) using the regression model established by the SMILE 4.0-VISULYZE system, thereby achieving satisfactory postoperative refractive outcomes.

In this study, patients scheduled for SMILE surgery at the investigators' hospital will be divided into two groups: a conventional group, where the input parameters are adjusted based on historical experience according to the patient's refractive error, and a 4.0-VISULYZE group, where the input parameters are optimized using the SMILE 4.0-VISULYZE system.

The investigators will compare the postoperative outcomes between the two groups, including uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical power, cylindrical power, spherical equivalent (SE), and the proportions of patients achieving postoperative visual acuity ≥0.8, ≥1.0, and ≥1.2 at 1 day, 10 days, 1 month, 3 months, 6 months, and 1 year post-surgery. Additionally, the investigators will evaluate the proportions of patients with postoperative SE within ±0.50D and ±1.0D, as well as postoperative cylindrical power within ±0.50D and ±1.0D, to assess the efficacy and safety of the SMILE 4.0-VISULYZE system in treating refractive errors.

Inclusion Criteria:

1. The diopter is relatively stable (the diopter increases within -0.50D per year for 2 consecutive years);
2. Age: 18 to 40 years old;
3. Optimal preoperative corrected visual acuity ≥4.8;
4. More than 2 weeks for soft contact lenses and more than 3 months for hard contact lenses before surgery
5. Patients who are willing to perform SMILE surgery

Exclusion Criteria:

1. Patients with history of eye surgery and trauma;
2. Patients with keratoconus tendency;
3. systemic connective tissue diseases and autoimmune diseases;
4. Patients with high blood pressure, diabetes and heart disease history;
5. Other eye disease history such as uveitis, scleritis and other eye inflammation patients;
6. Patients with scar constitution.