International Multicenter Study on SMILE Surgery

International Multicenter Study on Small Incision Lenticule Extraction(SMILE) Surgery

The purpose of this study is to carry out an international multicenter trial to get more convincing and valuable results of the SMILE surgery and compare the outcomes between the SMILE surgery and the FS-LASIK (femtosecond laser assisted-laser in situ keratomileusis) surgery.

The investigators hope to investigate the differences between the SMILE and the FS-LASIK surgery comprehensively, including the comparison of visual acuity, refraction, the correction of cylindrical diopter, the high order aberrations, the corneal biomechanics, the corneal ectasia, the characteristics of the changes of central corneal thickness and the complications. To meet the demands of a multi center trial, all the examination equipments should be same in each center, and this will limit the variations within a study

Study Overview

• Status: Unknown
• Conditions: Refractive Error
• Intervention / Treatment: Procedure: SMILE surgery; Other: FS-LASIK surgery

Detailed Description

Hypothesis: To compare the novel refractive surgery (SMILE, the intervention group) with traditional refractive surgery (FS-LASIK, the control group) in terms of visual acuity, the higher order aberrations, corneal biomechanical parameters and the complications. SMILE surgery might offer some advantages in some aspects compared with FS-LASIK surgery.

Study program

The procedures of the study are listed as follows:

All the participants accept the refractive surgery which were selected at first, and patients' routine postoperative examinations included UCVA, BCVA, slit lamp microscopy, non-contact IOP, corneal topography with the Scheimpflug tomography system, ocular higher order aberrations using the WASCA analyzer (Carl Zeiss Meditec AG), corneal biomechanical properties acquired by the Ocular Response Analyzer and/or the Corvis ST (Corvis ST, OCULUS, Wetzlar, Germany) at 1 week, 1 month, 3 months and 6 months follow-up periods after surgery.

Statistics:

Patients who have decided to choose the SMILE surgery or the FS-LASIK will be selected as participants. The propensity matching method will be used to choose proper cases for the two groups. The propensity matching method can be calculated by SPSS software. The independent variables include: the central corneal thickness (CCT), the Km (mean Pentacam keratometry), the spherical diopter (from manifest refraction), and the cylindrical diopter (from manifest refraction), the UCVA, the BCVA, the corneal resistance factor (CRF) and the corneal hysteresis (CH) (if the investigator have the Ocular Response Analyzer) of the cornea at preoperative. The closest score of eyes in the two groups will be matched.

The data will be preserved by each site, and will be systematically collected and analyzed by TianjinEH center. The statistical expert Dr Hayes from American Pacific University will be the statistical consultant, and will also in charge of the sample size calculation, the instructor of statistical analysis, and the quality control.

• Study Type: Interventional
• Enrollment (Anticipated): 1000
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Tianjin, China
    • Recruiting
    • Tianjin Eye Hospital
    • Contact: Yan Wang, director; Phone Number: +86-02227305083; Email: wangyan7143@vip.sina.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 41 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• be accompanied by a parent or guardian who is able to give informed consent as demonstrated by signing a record of informed consent;
• at baseline, be within the age range of 18 to 45 years old inclusive
• normal corneal morphology with no corneal nebula or corneal macula, the range of preoperative K2 (the steep curvature of the 3mm area at the center of cornea) from 38.0 to 47.0 diopter
• manifest spherical equivalent of -1.0 to -10.0 diopters (D)
• cylindrical diopter no more than -5.0D
• refractive diopter maintained stable for more than2 years
• preoperative BCVA≥0.8, and the scotopic pupil diameter≥5.0mm when measured by WASCA analyzer (Carl Zeiss Meditec AG)
• picked off soft contact lens for more than 2 weeks
• picked off RGP for more than 1 month
• preoperative corneal central thickness measured by Pentacam >500μm, non-contact IOP<21mmHg
• be willing to comply with the clinical trial visit schedule as directed by the investigator.

Exclusion Criteria:

• any corneal diseases, corneal operations, eyes trauma or systemic diseases history; keratoconus or tendency of keratoconus
• corneal macula and obvious pannus; current enrolment in another clinical trial/research project.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: SMILE surgery; Small incision lenticule extraction (SMILE) has become a novel and effective method for the correction of myopia and myopic astigmatism. It is a micro-invasive and flapless refractive procedure that has been proved to offer many advantages in terms of visual acuity, corneal sensitivity and corneal biomechanics compared with traditional refractive surgeries.	Procedure: SMILE surgery; SMILE surgery and FS-LASIK surgery are both effective method for the correction of myopia and myopic astigmatism. They have been proved to offer many advantages in terms of visual acuity, corneal sensitivity and corneal biomechanics compared with traditional refractive surgeries.
Other: FS-LASIK surgery; FS-LASIK surgery is femtosecond laser assisted- conventional refractive surgery and has also been proved to offer many advantages in terms of visual acuity, corneal sensitivity and corneal biomechanics compared with traditional refractive surgeries.	Other: FS-LASIK surgery; SMILE surgery and FS-LASIK surgery are both effective method for the correction of myopia and myopic astigmatism. They have been proved to offer many advantages in terms of visual acuity, corneal sensitivity and corneal biomechanics compared with traditional refractive surgeries.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
corrected visual acuity	change from baseline with EDTRS chart at 6 months

Secondary Outcome Measures

Outcome Measure	Time Frame
uncorrected visual acuity	change from baseline with EDTRS chart at 6 months
spherical diopter	change from baseline with manifest refraction at 6 months
cylindrical dioptor	change from baseline with manifest refraction at 6 months
central corneal thickness	change from baseline with the Pentacam system at 6 months
corneal curvature assessed by the Pentacam system	change from baseline with mean Pentacam keratometry at 6 months
corneal resistance factor assessed by the Ocular Response Analyzer	change from baseline at 6 months
corneal hysteresis assessed by the Ocular Response Analyzer	change from baseline at 6 months
deformation amplitude assessed by the Corvis ST system	change from baseline at 6 months
spherical aberration	change from baseline with the WASCA system at 6 months
coma aberration	change from baseline with the WASCA system at 6 months
complication	intraoperative and postoperative at 6 months

Collaborators and Investigators

• Sponsor: Tianjin Eye Hospital
• Collaborators: Alexandria University; Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University; Nethradhama Superspeciality Eye Hospital; Belgian Ocular Laser Centre; Jinan Mingshui Eye Hospital
• Investigators: Study Director: Yan Wang, director, Tianjin Eye Hospital; Principal Investigator: Sri Ganesh, professor, Nethradhama Superspeciality Eye Hospital; Principal Investigator: Bernard Heintz, professor, Belgian Ocular Laser Centre; Principal Investigator: Osama Ibrahim, professor, Cornea Center, Alexandria University; Principal Investigator: Keming Yu, professor, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University; Principal Investigator: Yulin Lei, professor, Jinan Mingshui Eye Hospital

Publications and helpful links

General Publications

• Wei S, Wang Y. Comparison of corneal sensitivity between FS-LASIK and femtosecond lenticule extraction (ReLEx flex) or small-incision lenticule extraction (ReLEx smile) for myopic eyes. Graefes Arch Clin Exp Ophthalmol. 2013 Jun;251(6):1645-54. doi: 10.1007/s00417-013-2272-0. Epub 2013 Feb 7. Erratum In: Graefes Arch Clin Exp Ophthalmol. 2013 Oct;251(10):2495-7.
• Wang Y, Bao XL, Tang X, Zuo T, Geng WL, Jin Y. [Clinical study of femtosecond laser corneal small incision lenticule extraction for correction of myopia and myopic astigmatism]. Zhonghua Yan Ke Za Zhi. 2013 Apr;49(4):292-8. Chinese.
• Wu D, Wang Y, Zhang L, Wei S, Tang X. Corneal biomechanical effects: small-incision lenticule extraction versus femtosecond laser-assisted laser in situ keratomileusis. J Cataract Refract Surg. 2014 Jun;40(6):954-62. doi: 10.1016/j.jcrs.2013.07.056. Epub 2014 Apr 18.
• Li X, Wang Y, Dou R. Aberration compensation between anterior and posterior corneal surfaces after Small incision lenticule extraction and Femtosecond laser-assisted laser in-situ keratomileusis. Ophthalmic Physiol Opt. 2015 Sep;35(5):540-51. doi: 10.1111/opo.12226. Epub 2015 Jun 18.
• Zhang J, Wang Y, Wu W, Xu L, Li X, Dou R. Vector analysis of low to moderate astigmatism with small incision lenticule extraction (SMILE): results of a 1-year follow-up. BMC Ophthalmol. 2015 Jan 24;15:8. doi: 10.1186/1471-2415-15-8.

Study record dates

Study Major Dates

• Study Start: September 1, 2016
• Primary Completion (Anticipated): September 1, 2019
• Study Completion (Anticipated): December 1, 2019

Study Registration Dates

• First Submitted: July 12, 2016
• First Submitted That Met QC Criteria: July 25, 2016
• First Posted (Estimate): July 26, 2016

Study Record Updates

• Last Update Posted (Actual): May 4, 2018
• Last Update Submitted That Met QC Criteria: May 3, 2018
• Last Verified: May 1, 2018

More Information

Terms related to this study

• Keywords: multicenter; SMILE surgery; FS-LASIK surgery
• Additional Relevant MeSH Terms: Eye Diseases; Refractive Errors
• Other Study ID Numbers: Tianjin EH-SMILE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No