Comparison of Femto LDV Z8 Corneal Lenticule Extraction for Advanced Refractive Correction (CLEAR) and Visumax Small Incision Lenticule Extraction (SMILE)

NCT06774651 | Recruiting DMC

• 1 other identifier: R1816/58/2021
• Study Type: observational
• Target: 65
• Locations: 1 country
• Sites: 1

Brief Summary

This observational study aims to compare two laser corrective procedures for treating myopia and myopic astigmatism: a novel refractive technique, the CLEAR procedure, and the established SMILE procedure. Participants will be randomized to undergo CLEAR in one eye and SMILE in the other. The investigators will evaluate and compare the two procedures based on the following aspects: refractive predictability (how accurate the vision correction is) by measuring the proportion of eyes close to the target prescription after surgery, clinical dry eye outcomes, changes in tear proteins, and corneal nerve changes at 1, 3, 6, and 12 months after both surgeries. Metabolomic features of the removed corneal tissue and how precisely the laser is centered during surgery will also be examined. Our hypothesis is that CLEAR provides equally good vision results as SMILE, and explore any extra benefits of CLEAR.

Conditions

Myopia

Keywords

CLEAR; FEMTO LDV Z8; SMILE; Visumax; Myopia

Outcome Measures

Primary Outcomes (1)

• Rate of refractive predictability

  Refractive predictability is defined as the proportion number of eyes achieving a postoperative spherical equivalent (SE) within ±1.0 D of the intended target. Uncorrected visual acuity (UCVA), refraction, and best corrected visual acuity (BCVA) will be recorded.

  1 year

Secondary Outcomes (14)

• Level of higher order aberrations

  1 year

• Tear Break Up Time (TBUT)

  1 year

• Concentration of tear neuromediators assessed by enzyme-linked immunosorbent assay

  1 year

• Corneal sensitivity measurements assessed by Cochet-Bonnet esthesiometer

  1 year

• NEI score

  1 year

Study Arms (2)

1. CLEAR surgery eyes

Eyes that have undergone CLEAR procedures.

Procedure: Procedure: Corneal lenticule extraction for advanced refractive correction (CLEAR)

2. SMILE surgery eyes

Eyes that have undergone SMILE procedures.

Procedure: Procedure: Small Incision Lenticule Extraction (SMILE)

Interventions

Procedure: Corneal lenticule extraction for advanced refractive correction (CLEAR) PROCEDURE

Routinely conducted procedure using FEMTO LDV Z8 laser system for correction of Myopia.

1. CLEAR surgery eyes

Procedure: Small Incision Lenticule Extraction (SMILE) PROCEDURE

Routinely conducted procedure using VisuMax laser system for correction of Myopia.

Also known as: SMILE

2. SMILE surgery eyes

Eligibility Criteria

• Age: 21 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

A total of 65 subjects (130 eyes- 65 CLEAR eyes and 65 SMILE eyes) will be recruited in the study from refractive clinic at Singapore National Eye Centre.

You may qualify if:

• \>/= 21 years of age and \</= 50 years of age.
• Cycloplegic spherical equivalent of \>-1.00D
• Refractive cylinder -2.00 D or less; anisometropia \<1.00D
• 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 12-month period.

You may not qualify if:

• Progressive or unstable myopia and/or astigmatism.
• Clinical or corneal topographic evidence of keratoconus.
• Patients who want bilateral SMILE procedure
• Patients who want extracted corneal lenticule to be stored for future refractive surgery.
• 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 treatment zone.
• Corneal vascularisation within 1mm of the corneal treatment 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 Eye Research Institute: lead

Study Sites (1)

Singapore National Eye Centre

Singapore, S169856, Singapore

RECRUITING

Related Publications (1)

• Yu M, Liu C, Lee IXY, Hsu VW, Wong RKT, Anam A, Lim R, Mehta JS, Liu YC. Randomized controlled trial on corneal denervation, neuroinflammation and ocular surface in corneal lenticule extraction for advanced refractive correction (CLEAR) and small incision lenticule extraction (SMILE). Eye Vis (Lond). 2025 Apr 1;12(1):12. doi: 10.1186/s40662-025-00429-1.

  PMID: 40165267 DERIVED

MeSH Terms

Conditions

Myopia

Condition Hierarchy (Ancestors)

Refractive Errors; Eye Diseases

Study Officials

• Jodhbir S Mehta, MD, FRCS

  Singapore National Eye Centre

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jodhbir S Mehta, MD, FRCS

CONTACT

6322 7478; jodhbir.s.mehta@singhealth.com.sg

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 30, 2024
• First Posted: January 14, 2025
• Study Start: March 1, 2023
• Primary Completion: October 31, 2025
• Study Completion: December 31, 2025
• Last Updated: January 14, 2025

Record last verified: 2024-12

Data Sharing

• IPD Sharing: Will not share

Locations

SG (1)