Randomized, Non-inferiority Trial Comparing SMILE and LASIK

NCT01216475 | Unknown DMC

• 1 other identifier: R788/72/2010
• Study Type: interventional
• Target: 70
• Locations: 1 country
• Sites: 1

Brief Summary

Background: Small Incision Lenticule Extraction or SMILE is a novel form of 'flapless' corneal refractive surgery that was adapted from Refractive Lenticule Extraction (ReLEx). SMILE uses only one femtosecond laser to complete the refractive surgery, potentially reducing surgical time, side effects and cost. If successful, SMILE could potentially replace the current, widely practiced Laser In-situ Keratomileusis or LASIK. The aim of this study is to evaluate whether SMILE is non-inferior to LASIK in terms of refractive outcomes at 3-months post-operatively. Methods/ Design: Single tertiary center, parallel group, single-blinded, paired-eye design, non-inferiority, randomized controlled trial. Participants who are eligible for LASIK will be enrolled for study after informed consent. Each participant will be randomized to receive SMILE and LASIK in each eye. Our primary hypothesis (stated as null) in this non-inferiority trial would be that SMILE differs from LASIK in adults (\>21 years old) with myopia (\> -3.00D) at a tertiary eye center in terms of refractive predictability at 3 months post-operatively. Our secondary hypothesis (stated as null) in this non-inferiority trial would be that SMILE differs from LASIK in adults (\>21 years old) with myopia (\> -3.00D) at a tertiary eye center in terms of other refractive outcomes (efficacy, safety, higher-order aberrations) at 3 months post-operatively. Our primary outcome is refractive predictability, which is one of several standard refractive outcomes, defined as the proportion of eyes achieving a postoperative spherical equivalent (SE) within ±0.50 diopter (D) of the intended target. Randomization will be performed using random allocation sequence generated by a computer with no blocks or restrictions, and implemented by concealing the number-coded surgery within sealed envelopes until just before the procedure. In this single-blinded trial, subjects and their caregivers will be blinded to the assigned treatment in each eye. Discussion: This novel trial will provide information on whether SMILE has comparable, if not superior, refractive outcomes compared to the established LASIK for myopia, thus providing evidence for translation into clinical practice.

Conditions

Myopia; Astigmatism; Hypermetropia

Outcome Measures

Primary Outcomes (1)

• Refractive predictability

  Defined as the proportion number of eyes achieving a postoperative spherical equivalent (SE) within ±0.50 diopter (D) of the intended target.

  3 months Post-operative

Secondary Outcomes (3)

• Efficacy

  3 months Post-operative

• Safety

  3 months Post-operative

• Contrast sensitivity

  3 months Post-operative

Study Arms (2)

Femtosecond LASIK

ACTIVE COMPARATOR

2 lasers refractive procedure

Procedure: Femtosecond LASIK

SMILE

EXPERIMENTAL

Small incision lenticule extraction (SMILE)

Procedure: Small incision lenticule extraction (SMILE)

Interventions

Femtosecond LASIK PROCEDURE

LASIK consists of two steps: the first step involves the formation of a corneal flap and the second one is when the excimer ablation is performed in the corneal stromal bed. Femtosecond lasers (FL) have been widely used in LASIK surgery to fashion the corneal flap. The laser will cut a lamellar followed by a vertical corneal incision. We are able to produce a vertical cut since the Femtosecond laser can deliver laser pulses of 1 micron diameter at a preselected depth in the cornea, which then expands to 2 to 3 microns with the formation of a cavitation bubble. These pulses create micro-photodisruption of the corneal tissue by the formation of an expanding bubble of carbon dioxide and water, which in turn cleaves the tissue and creates a plane of separation. The flap is then removed to expose the stroma and the refractive treatment is done by the excimer laser over the denuded stroma.

Also known as: Blade-less LASIK

Femtosecond LASIK

Small incision lenticule extraction (SMILE) PROCEDURE

Patient's eye will be centered and docked with the curved interface cone before application of suction fixation. First, the posterior surface of the refractive lenticule (spiral in), then the lenticule border is created. The anterior surface of the refractive lenticule (spiral out) is then formed which extended beyond the posterior lenticule diameter by 0.5mm to form the anterior flap and is followed by a rim cut. After the suction is released, a Siebel spatula is inserted under the flap near the hinge before the flap is seperated and reflected. The edge of the refractive lenticule is separated from the stromal bed with a sinsky hook and the posterior border of the lenticule gently separated with the Siebel spatula and removed through small incision.

SMILE

Eligibility Criteria

• Age: 21 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• years of age or older.
• Cycloplegic spherical equivalent of \>-2.00D
• Refractive cylinder -4.00 D or less, Anisometropia of \>1D
• Best spectacle corrected visual acuity (BSCVA) of 6/12 or better in BOTH eyes.
• Spherical or cylindrical error has progressed at -0.50D or less per year from date of baseline measurement.
• Contact lens wearers must have removed contact lenses at least two (2) weeks before the baseline measurement.
• No evidence of irregular astigmatism on corneal topography.
• Available to attend post-operative examinations for a 3 month period.

You may not qualify if:

• Progressive or unstable myopia and/or astigmatism.
• Clinical or corneal topographic evidence of keratoconus.
• Residual, recurrent or active ocular disease such as uveitis, severe dry eyes, severe allergic eye disease, glaucoma, visually significant cataract and retinal disease.
• Previous corneal surgery or trauma within the corneal flap zone.
• Patent corneal vascularization within 1mm of the corneal flap zone.
• Taking systemic medications likely to affect wound healing, such as corticosteroids and antimetabolites.
• Systemically immunocompromised.
• Systemic disease likely to affect wound healing, such as diabetes, connective tissue disease and severe atopy.
• Pregnant or nursing.

Sponsors & Collaborators

• Singapore National Eye Centre: lead

Study Sites (1)

Singapore National Eye Centre

Singapore, Singapore, 168751, Singapore

RECRUITING

Related Publications (2)

• Sekundo W, Kunert K, Russmann C, Gille A, Bissmann W, Stobrawa G, Sticker M, Bischoff M, Blum M. First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results. J Cataract Refract Surg. 2008 Sep;34(9):1513-20. doi: 10.1016/j.jcrs.2008.05.033.

  PMID: 18721712 RESULT

• Ang M, Tan D, Mehta JS. Small incision lenticule extraction (SMILE) versus laser in-situ keratomileusis (LASIK): study protocol for a randomized, non-inferiority trial. Trials. 2012 May 31;13:75. doi: 10.1186/1745-6215-13-75.

  PMID: 22647480 DERIVED

MeSH Terms

Conditions

Myopia; Astigmatism; Hyperopia

Condition Hierarchy (Ancestors)

Refractive Errors; Eye Diseases

Study Officials

• Donald T Tan, FRCS(Ed),

  Singapore National Eye Centre

  STUDY DIRECTOR

• Jodhbir S Mehta, FRCS (ed)

  SNEC

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Donald T Tan, FRCS(Ed),

CONTACT

6562263395; snecdt@pacific.net.sg

Jodhbir S Mehta, FRCS(Ed)

CONTACT

65622772565; jodmehta@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof Jod Mehta

Study Record Dates

• First Submitted: September 8, 2010
• First Posted: October 7, 2010
• Study Start: February 1, 2012
• Primary Completion: November 1, 2016
• Study Completion: September 1, 2017
• Last Updated: July 20, 2016

Record last verified: 2016-07

Data Sharing

• IPD Sharing: Will not share

Locations

SG (1)