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The Impact of 'A Miss Is as Good as a Mile': Is Compensation Necessary for Minimal Ocular Deviation in Myopic Laser Surgery?

NCT07512115 · Status: RECRUITING · Phase: NA · Type: INTERVENTIONAL · Enrollment: 224

Last updated 2026-07-07

No results posted yet for this study

Summary

The goal of this clinical trial is to evaluate the effect of intraoperative kappa-angle compensation on postoperative visual quality in patients undergoing small incision lenticule extraction (SMILE) using the VisuMax 800 platform. The study will enroll patients with myopia and a kappa-angle offset \< 0.2 mm.

The main questions it aims to answer are:

Does intraoperative kappa-angle compensation reduce postoperative higher-order aberrations after SMILE? Does kappa-angle compensation improve postoperative visual quality and refractive outcomes compared with no compensation?

Researchers will compare SMILE with intraoperative kappa-angle compensation to SMILE without compensation to determine whether compensation leads to better optical quality and visual performance.

Participants will:

Undergo SMILE surgery with or without intraoperative kappa-angle compensation Complete scheduled postoperative examinations at 1 week, 1 month, 3 months, and 6 months after surgery Receive measurements of visual acuity, refraction, higher-order aberrations, contrast sensitivity, and safety outcomes

Conditions

  • Myopia
  • Refractive Ametropia

Interventions

PROCEDURE

Apply compensation to the Kappa angle.

SMILE PRO is an upgraded version/procedural designation of SMILE (Small Incision Lenticule Extraction) performed on the ZEISS VisuMax 800 femtosecond laser platform and remains, in essence, an all-femtosecond corneal refractive procedure. Its basic principle is to use a femtosecond laser to create a lenticule within the corneal stroma together with a small incision, and then remove the lenticule through that incision, thereby reshaping the corneal curvature to correct myopia and astigmatism. In the compensation group, during preoperative parameter input, a fixed intraoperative laser centration compensation of 0.1 mm was uniformly applied to all study eyes meeting the inclusion criteria to achieve a quantitative adjustment of the treatment center toward the visual axis.

PROCEDURE

Apply no compensation to the Kappa angle

SMILE PRO is an upgraded version/procedural designation of SMILE (Small Incision Lenticule Extraction) performed on the ZEISS VisuMax 800 femtosecond laser platform and remains, in essence, an all-femtosecond corneal refractive procedure. Its basic principle is to use a femtosecond laser to create a lenticule within the corneal stroma together with a small incision, and then remove the lenticule through that incision, thereby reshaping the corneal curvature to correct myopia and astigmatism. In the non-compensation group, no kappa-angle-based laser centration compensation was applied intraoperatively, and the treatment center was set according to the system's default centration method.

Sponsors & Collaborators

  • Zhongshan Ophthalmic Center, Sun Yat-sen University

    lead OTHER

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
40 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2026-04-08
Primary Completion
2027-05-30
Completion
2027-05-30

Countries

  • China

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07512115 on ClinicalTrials.gov