0.05 D precision refraction to improve SMILE and FS‑LASIK vision

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

This project will try using very fine (0.05 diopter) refraction measurements before SMILE or FS‑LASIK for adults 18–40 to see if they get sharper vision after surgery.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 600 (estimated)
• Ages: 18 Years to 40 Years
• Sex: All
• Sponsor: Affiliated Hospital of Nantong University (other)
• Locations: 1 site (Nantong, Jiangsu)
• Trial ID: NCT07146828 on ClinicalTrials.gov

What this trial studies

This prospective study enrolls patients scheduled for SMILE or FS‑LASIK at the Affiliated Hospital of Nantong University and measures preoperative refraction with a binocular wavefront aberrometer at 0.05 D increments. The 0.05 D refraction values will be entered into the VisuMax Precision 4.0 system for SMILE or applied with the FS‑LASIK manufacturer nomogram to guide surgical input. Patients will be followed at 10 days, 1 month, 3 months, 6 months and 1 year to record uncorrected and best‑corrected visual acuity, spherical and cylindrical power, spherical equivalent, and higher‑order aberrations. Primary outcomes are postoperative UCVA and BCVA and the proportion of patients reaching specified UCVA thresholds, with secondary outcomes including residual refractive error and aberrations.

Who should consider this trial

Good fit: Adults aged 18–40 with stable myopic refraction, good preoperative corrected visual acuity, appropriate contact lens washout, and who plan to undergo SMILE or FS‑LASIK are ideal candidates.

Not a fit: Patients with prior eye surgery or trauma, keratoconus or suspected ectasia, active ocular inflammation, significant systemic disease (eg, uncontrolled hypertension, diabetes, heart disease), scar tendency, or unstable refraction are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, this approach could reduce residual refractive errors after corneal refractive surgery and improve uncorrected visual acuity and overall visual quality.

How similar studies have performed: Prior reports document residual refractive errors after SMILE and that many people detect changes smaller than 0.25 D, but applying 0.05 D surgical inputs is relatively novel and has limited direct outcome data.

Eligibility criteria

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.

Where this trial is running

Nantong, Jiangsu

• Binocular Wavefront Optometry Machine — Nantong, Jiangsu, China (RECRUITING)

Study contacts

• Study coordinator: Ying Yu, MD

Conditions: Refractive Surgery, Corneal refractive surgery, SMILE, FS-LASIK, 0.05 D precision refraction