Low vs high kappa-angle compensation during SMILE with VisuMax 800

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

In this single-center, randomized study, adults aged 18–40 with stable myopia or myopic astigmatism and a sizable kappa offset will be assigned to one of two intraoperative visions for centering the SMILE treatment. The VisuMax 800 laser’s machine-vision alignment allows the surgeon to compensate for the visual axis offset during the procedure. The primary question is whether low kappa-angle compensation reduces higher-order aberrations compared with high compensation, with secondary outcomes including simple visual acuity, refractive accuracy, contrast sensitivity, and subjective visual quality. The trial aims to clarify the optimal intraoperative centering strategy for patients with larger kappa offsets undergoing SMILE. Outcome measures include postoperative visual quality and stability of refractive results.

Why it matters

Who can join: the full rules

Inclusion Criteria:

1. Age range: 18 - 40 years old. Patients with stable refractive status for \>= 1 year, having myopia or myopic astigmatism, with refractive power within the range of SMILE procedure.
2. Normal corneal morphology and corneal thickness meeting the surgical requirements.
3. Best corrected visual acuity (CDVA) before surgery \>= 1.0.
4. The kappa angle-related offset coordinates (x, y) obtained before surgery, with the absolute value of either \|x\| or \|yl\| of any eye \>= 0.20mm.
5. Voluntary to undergo SMILE surgery on the VISUMAX800 platform, understanding the random grouping scheme and signing the informed consent form.

Exclusion Criteria:

1. History of prior ocular surgery, significant ocular trauma, or presence of corneal or ocular diseases that may affect the safety of refractive surgery.
2. Severe systemic diseases that may affect ocular healing or surgical safety.
3. Females who are pregnant or lactating.
4. Inability to cooperate as required to complete the procedure or follow-up visits.

Where it's running

• Zhongshan Ophthalmic Center
  Guangzhou, Guangdong, China Recruiting

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.