Recruiting NCT06992011
A Randomized Controlled Trial Comparing Clinical Effectiveness of SMILE Versus SMILE Xtra in Myopia
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: SMILE, SMILE Xtra.
- Who it may be relevant to
- Registry conditions: Myopia. Basic parameters: 18 years — 50 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- China
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Overview
To evaluate and compare the clinical efficacy, biomechanical stability, and optical quality of SMILE and SMILE Xtra procedures in patients with myopia through a randomized controlled trial
Interventions
- Procedure SMILE
Small Incision Lenticule Extraction - Procedure SMILE Xtra
Small Incision Lenticule Extraction combined with Corneal Cross-linking (SMILE Xtra)
Primary outcome measures
- visual acuity [Time frame: 1 week, 1 month,3 months， 6 months, 12 months, 24 months, and 36 months]
Eligibility criteria
Inclusion criteria
- Age 18-50 years
- MRSE (Manifest Refraction Spherical Equivalent) -6.00D to -10.00D with refractive changes within ±0.50D in past 2 years
- CDVA (Corrected Distance Visual Acuity) ≥ 20/25
- Myopia progression ≤ 0.50D/year for ≥2 years
- RST (Residual Stromal Thickness) ≥ 250μm after lenticule removal
- Contact lens discontinuation as per protocol
Exclusion criteria
- Other eye diseases (keratoconus, glaucoma, etc.)
- Corneal scarring, cataracts affecting observation
- Systemic diseases affecting surgery compliance
- Prior ocular surgeries
- Pregnancy, breastfeeding, or menstruation
- Drug allergies to surgical medication
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Single blind
- Primary purpose
- Treatment
Study locations
China · 1 center
- Zhongshan Hospital — Shanghai
Publications
- Cong J, Lin X, Yuan J, Li X, Liu W, Mao X, Zheng C, Liu S, Feng Q, Dong C, Feng C, Yuan Y, Dai J. Comparing Efficacy and Corneal Biomechanics Between KLEx and KLEx Xtra in High Myopia: A 1-Year Prospective Randomized Study. Ophthalmol Ther. 2026 Apr;15(4):1355-1374. doi: 10.1007/s40123-026-01340-1. Epub 2026 Mar 4. PMID 41781518
Identifiers
NCT: NCT06992011 · B2024-267R-1