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

NCT07146828 | Recruiting

• 1 other identifier: 2025-K173
• Study Type: interventional
• Target: 600
• Locations: 1 country
• Sites: 1

Brief Summary

In recent years, the incidence of myopia has been high globally and is exhibiting a rapid upward trend, with projections estimating it will reach 49.8% by 2050. Corneal refractive surgery has become a primary method for correcting myopia, demonstrating significant efficacy and favorable safety. However, studies indicate that overcorrection or undercorrection can occur following refractive surgery. Reports have shown that three months post-SMILE surgery, 20% of eyes had residual refractive errors ≥ 0.50 D, and 6% had errors ≥ 1.00 D. We hypothesize that this may be related to imprecise preoperative refraction, subsequently affecting postoperative visual quality. Due to limitations in lens manufacturing precision, the widely used increment for sphere correction remains 0.25 D. However, this may prevent some patients from achieving their optimal corrected state. Studies have reported that 95% of individuals are sensitive to diopter changes below 0.25 D, and 44% can distinguish changes smaller than 0.125 D. Other research suggests that adjusting spherical power in 0.05 D increments yields better corrected visual acuity. Furthermore, scholars have reported that 0.05 D precision refraction can significantly improve the red-green balance test rate, enabling myopic patients to achieve better visual quality. Therefore, improving refraction precision could provide patients with superior visual outcomes. Currently, the Binocular Wavefront Optometry Machine (BWFOM, Ai-Zhitong Medical Technology Co., Ltd., Zhejiang, China) can perform objective and subjective refraction with 0.05 D increments for both sphere and cylinder correction, while also separately measuring higher-order aberrations (HOAs) and lower-order aberrations (LOAs). Given the scarcity of research on the outcomes of 0.05 D refraction for SMILE and FS-LASIK procedures, this study aims to evaluate visual acuity, aberrations, and refractive status in patients following SMILE and FS-LASIK surgery. The primary objective is to investigate whether preoperative 0.05 D precision refraction using the BWFOM can enhance postoperative visual quality for SMILE and FS-LASIK patients.

Conditions

Refractive Surgery

Keywords

Corneal refractive surgery; SMILE; FS-LASIK; 0.05 D precision refraction

Outcome Measures

Primary Outcomes (5)

• Postoperative spherical equivalent

  It calculated as: SE = Sphere + ½ Cylinder

  Preoperatively, and at 1 day, 10 days, 1 month, 3 months, 6 months, and 1 year postoperatively

• Postoperative corrected distance visualacuity

  Using the standard logarithmic visual acuity chart, with units in logMAR.

  Preoperatively, and at 1 day, 10 days, 1 month, 3 months, 6 months, and 1 year postoperatively

• Postoperative uncorrected distance visual acuity

  Using the standard logarithmic visual acuity chart, with units in logMAR

  Preoperatively, and at 1 day, 10 days, 1 month, 3 months, 6 months, and 1 year postoperatively

• spherical diopter

  Spherical diopter (D) is the unit of measurement for the refractive (light-bending) power of a spherical lens (or the spherical component of a corrective lens) used to correct myopia (nearsightedness) or hyperopia (farsightedness).

  Preoperatively, and at 1 day, 10 days, 1 month, 3 months, 6 months, and 1 year postoperatively

• cylinder diopter

  The unit of measurement for the lens power required to correct astigmatism, representing the difference in refractive power between the steepest and flattest meridians (axes) of the eye or lens

  Preoperatively, and at 1 day, 10 days, 1 month, 3 months, 6 months, and 1 year postoperatively

Study Arms (2)

traditional group

NO INTERVENTION

The traditional group had their infusion rates based on past experience.

0.05 D refraction Group

EXPERIMENTAL

The 0.05 D refraction group had their infusion rates precisely calibrated using 0.05 D refraction by the Binocular Wavefront Optometry Machine (BWFOM, Ai-Zhitong Medical Technology Co., Ltd., Zhejiang, China)

Device: Binocular Wavefront Optometry Machine (BWFOM, Ai-Zhitong Medical Technology Co., Ltd., Zhejiang, China)

Interventions

Binocular Wavefront Optometry Machine (BWFOM, Ai-Zhitong Medical Technology Co., Ltd., Zhejiang, China) DEVICE

The 0.05 D refraction group had their infusion rates precisely calibrated using 0.05 D refraction by the Binocular Wavefront Optometry Machine

0.05 D refraction Group

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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.

Sponsors & Collaborators

• Affiliated Hospital of Nantong University: lead

Study Sites (1)

Binocular Wavefront Optometry Machine

Nantong, Jiangsu, 226001, China

RECRUITING

Central Study Contacts

Ying Yu, MD

CONTACT

+86 159 9662 1616; yuying.2009@163.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 15, 2025
• First Posted: August 28, 2025
• Study Start: January 1, 2025
• Primary Completion: October 1, 2025
• Study Completion (Estimated): October 1, 2026
• Last Updated: August 28, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)