Clinical Application Research of 5-Degree (0.05 D) Precision Optometry in Corneal Refractive Surgery

This study aims to optimize the surgical parameters of corneal refractive surgery (SMILE and FS-LASIK) by utilizing 0.05 D high-precision refraction achieved through a binocular wavefront aberrometer, thereby improving patients' postoperative visual outcomes. The prospective study design involves patients scheduled for corneal refractive surgery at our hospital.

The research consists of two parts:

Part One: Performing 0.05 D precision refraction on myopic patients using the binocular wavefront aberrometer.

Part Two: Applying the obtained refraction results (in increments of 0.05 D) for refractive correction in patients undergoing SMILE and FS-LASIK surgery.

Specific procedures include:

Screening eligible patients who voluntarily choose SMILE or FS-LASIK. Preoperatively inputting the patients' 0.05 D refraction data into the SMILE platform (VisuMax Precision 4.0 - VISULYZE system) or the FS-LASIK system (applying the manufacturer-provided nomogram for undercorrection).

Utilizing the system-recommended input values for correcting refractive errors during surgery.

Conducting postoperative follow-up examinations at 10 days, 1 month, 3 months, 6 months, and 1 year.

Evaluation metrics include:

• Primary Endpoint Indicators:

Postoperative uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical power, cylindrical power, spherical equivalent (SE), and aberrations.

Proportion of patients achieving postoperative UCVA ≥ 0.8, ≥ 1.0, and ≥ 1.2. Proportion of patients with postoperative SE within ±0.50 D and ±1.0 D. Proportion of patients with postoperative astigmatism (cylinder) within ±0.50 D and ±1.0 D.

Postoperative efficacy index and safety index.

• Safety Indicators:

Intraocular pressure (IOP). Anterior segment examination.

Inclusion criteria

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

Exclusion criteria

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