Clinical trial NCT02844556: International Multicenter Study on SMILE Surgery
Official title: International Multicenter Study on Small Incision Lenticule Extraction(SMILE) Surgery
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Refractive Error
Keywords: SMILE surgery
FS-LASIK surgery
multicenter
Lead sponsor: Tianjin Eye Hospital
Sponsor class: OTHER
Collaborators: name: Nethradhama Superspeciality Eye Hospital
name: Alexandria University
name: Belgian Ocular Laser Centre
name: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
name: Jinan Mingshui Eye Hospital
First posted: 2016-07-26
Enrollment: 1000
Sex: ALL
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: 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

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.

Eligibility criteria: 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.

Primary outcomes:
measure: corrected visual acuity
timeFrame: change from baseline with EDTRS chart at 6 months
Secondary outcomes:
measure: uncorrected visual acuity
timeFrame: change from baseline with EDTRS chart at 6 months
measure: spherical diopter
timeFrame: change from baseline with manifest refraction at 6 months
measure: cylindrical dioptor
timeFrame: change from baseline with manifest refraction at 6 months
measure: central corneal thickness
timeFrame: change from baseline with the Pentacam system at 6 months
measure: corneal curvature assessed by the Pentacam system
timeFrame: change from baseline with mean Pentacam keratometry at 6 months
measure: corneal resistance factor assessed by the Ocular Response Analyzer
timeFrame: change from baseline at 6 months
measure: corneal hysteresis assessed by the Ocular Response Analyzer
timeFrame: change from baseline at 6 months
measure: deformation amplitude assessed by the Corvis ST system
timeFrame: change from baseline at 6 months
measure: spherical aberration
timeFrame: change from baseline with the WASCA system at 6 months
measure: coma aberration
timeFrame: change from baseline with the WASCA system at 6 months
measure: complication
timeFrame: intraoperative and postoperative at 6 months
Other outcomes:
Locations:
city: Tianjin
country: China
facility: Tianjin Eye Hospital
Study officials:
affiliation: Tianjin Eye Hospital
name: Yan Wang, director
role: STUDY_DIRECTOR
affiliation: Nethradhama Superspeciality Eye Hospital
name: Sri Ganesh, professor
role: PRINCIPAL_INVESTIGATOR
affiliation: Belgian Ocular Laser Centre
name: Bernard Heintz, professor
role: PRINCIPAL_INVESTIGATOR
affiliation: Cornea Center, Alexandria University
name: Osama Ibrahim, professor
role: PRINCIPAL_INVESTIGATOR
affiliation: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
name: Keming Yu, professor
role: PRINCIPAL_INVESTIGATOR
affiliation: Jinan Mingshui Eye Hospital
name: Yulin Lei, professor
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.
citation: 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.
citation: 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.
citation: 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.
citation: 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.