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MyopiaNCT06477081

KLEx Versus FS-LASIK for the Treatment of Myopia and Compound Myopic Astigmatism

A study testing FS-LASIK procedure and KLEx in people with Myopia and Astigmatism, run by Instituto de Oftalmología Fundación Conde de Valenciana at 1 site in Mexico.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

FemtoLASIK is a type of laser eye surgery used to correct vision problems such as nearsightedness, farsightedness, and astigmatism. It involves two main steps: creating a flap and reshaping the cornea. Read more about this study

Who is it for?
Ages 21 years and olderHealthy volunteers can take part
Conditions the study is for
Myopia, Astigmatism, Myopic Astigmatism
What is being tested?
FS-LASIK procedure and KLEx
Type of treatment
Surgery or procedure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
80 participants
Where
1 siteMexico
Study dates
1 Aug 2024to 1 Mar 2027
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 21 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Age 21 years or older
  • Corneal tomography without alterations
  • Myopia between -0.50 and -12.00 D
  • Astigmatism between -0.50 and -6.00 D

Who cannot join

  • Previous eye surgeries
  • Pregnancy
  • Progressive or unstable myopia and/or compound myopic astigmatism
  • Ocular surface disease

Trial locations and contacts

1 site in 1 country.

Mexico1 site
  • Instituto de Oftalmología Conde de Valenciana

    Mexico City, Mexico City, 06800

Other trials in Mexico

About this study

Official title: Keratorefractive Lenticule Extraction (KLEx) Versus Femtosecond Laser-assisted in Situ Keratomileusis (FS-LASIK) for the Treatment of Myopia and Compound Myopic Astigmatism

FemtoLASIK is a type of laser eye surgery used to correct vision problems such as nearsightedness, farsightedness, and astigmatism. It involves two main steps: creating a flap and reshaping the cornea. Refractive lenticule extraction, (KLEx) is another laser eye surgery method to correct vision issues, which involves creating and extracting a lenticule without the need of a flap. The investigators will evaluate and compare the efficacy and safety of these two procedures.

Read the detailed description

Keratorefractive lenticule extraction (KLEx) is a refractive surgery technique that does not require the creation of a flap to correct the defects. The potential advantages of this technique are related to the absence of a flap, which could make it the gold standard of refractive surgery. On the other hand, femtosecond-assisted laser in-situ keratomileusis (FS-LASIK) is the most widely practiced refractive surgery worldwide, as it offers excellent visual outcomes but does require the creation of a flap to correct the defects. The objective of this study is to evaluate the effectiveness and safety of KLEx versus FS-LASIK as a treatment option in patients with myopia or compound myopic astigmatism. This is a prospective randomized study. A total of 80 participants will be randomized into two groups, the KLEx group and FS-LASIK group. Following randomization, participants will be followed on the first day after the surgery, 1 week, 1, 3, 6, and 12 months. The primary outcome is the refractive predictability at every postoperative point after surgery, which is the proportion of the number of eyes achieving a postoperative spherical equivalent within ± 0.5 diopters of the intended target. Secondary outcome parameters include quality vision measurements, refraction, visual acuity, and adverse events.

Being tested
FS-LASIK procedure, KLEx
Keywords
KLEx, LASIK, FS-LASIK, Refractive Surgery, Astigmatism, Myopia
Medical subject headings
Myopia, Astigmatism

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • FS-LASIK procedureProcedure or surgery

    For the FS-LASIK technique, the following steps will be followed: application of topical anesthesia to mitigate discomfort and pain throughout the procedure, and the patient will be covered with a sterile drape. Subsequently, the patient will be aligned to artificially flatten the entire corneal surface, ensuring head stability with a slight tilt to optimize surgical access and avoid nasal interference. The femtosecond laser system use will be the ATOS operating system (Schwind eye-tech-solutions, Mainparkstraße 6-10, 63801 Kleinostheim, Germany), which is responsible for creating a corneal incision to create the flap, with controlled precision to ensure proper separation of corneal layers. The excimer laser will be the Amaris (Schwind eye-tech-solutions, Mainparkstraße 6-10, 63801 Kleinostheim, Germany), responsible for performing refractive correction on the cornea through selective photoablation. Following photoablation, the flap will be carefully repositioned, and upon completion o

  • KLExProcedure or surgery

    For the KLEx technique, the following steps will be followed: after topical anesthesia, a sterile drape is placed over the patient, and a speculum is inserted into the eye, centered, and aligned with a curved interface cone before applying suction. The laser used will be the ATOS operating system (Schwind eye-tech-solutions, Mainparkstraße 6-10, 63801 Kleinostheim, Germany), which performs photo-dissection starting from the posterior surface of the refractive lenticule, followed by the creation of the lenticule edge. The anterior surface of the refractive lenticule is formed by extending beyond the posterior diameter of the lenticule by 0.5 mm to form the anterior flap, followed by a peripheral cut. Specific FS laser parameters are employed for each patient. Subsequently, the suction is released, and a Siebel spatula is used to separate and reflect the flap. Finally, the refractive lenticule is extracted using toothless forceps through the small incision. Once the procedure is complete

Study groups in NCT06477081
Study groupRoleWhat they receive
FemtoLASIKActive comparatorFor the FS-LASIK technique, the following steps will be followed: application of topical anesthesia to mitigate discomfort and pain throughout the procedure, and the patient will be covered with a sterile drape. Subsequently, the patient will be aligned to artificially flatten the entire corneal surface, ensuring head stability with a slight tilt to optimize surgical access and avoid nasal interference. The femtosecond laser system use will be the ATOS operating system (Schwind eye-tech-solutions, Mainparkstraße 6-10, 63801 Kleinostheim, Germany), which is responsible for creating a corneal incision to create the flap, with controlled precision to ensure proper separation of corneal layers. The excimer laser will be the Amaris (Schwind eye-tech-solutions, Mainparkstraße 6-10, 63801 Kleinostheim, Germany), responsible for performing refractive correction on the cornea through selective photoablation. Following photoablation, the flap will be carefully repositioned, and upon completion
Receives: Procedure: FS-LASIK procedure
Keratorefractive lenticule extractionActive comparatorFor the KLEx technique, the following steps will be followed: after topical anesthesia, a sterile drape is placed over the patient, and a speculum is inserted into the eye, centered, and aligned with a curved interface cone before applying suction. The laser used will be the ATOS operating system (Schwind eye-tech-solutions, Mainparkstraße 6-10, 63801 Kleinostheim, Germany), which performs photo-dissection starting from the posterior surface of the refractive lenticule, followed by the creation of the lenticule edge. The anterior surface of the refractive lenticule is formed by extending beyond the posterior diameter of the lenticule by 0.5 mm to form the anterior flap, followed by a peripheral cut. Specific FS laser parameters are employed for each patient. Subsequently, the suction is released, and a Siebel spatula is used to separate and reflect the flap. Finally, the refractive lenticule is extracted using toothless forceps through the small incision. Once the procedure is complet
Receives: Procedure: KLEx

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Uncorrected Visual Acuity

    Visual acuity without correction after surgery.

    Measured: Day 1, week 1, months 1, 3, 6 & 12th after surgery.

Secondary outcomes (7)
  1. Postoperative spherical equivalent

    Overall refractive power that has both spherical and cylindrical components.

    Measured: Day 1, week 1, months 1, 3, 6 & 12th after surgery.

  2. Corrected Distance Visual Acuity

    Visual acuity after surgery with refractive correction

    Measured: Day 1, week 1, months 1, 3, 6 & 12th after surgery.

  3. Loss of 2 or more lines of BCVA

    Loss of 2 or more lines of best corrected visual acuity

    Measured: Day 1, week 1, months 1, 3, 6 & 12th after surgery.

  4. Eyes with 0.5 Diopters within refractive target.

    Proportion of eye within 0.5 Diopters of refactive target.

    Measured: Day 1, week 1, months 1, 3, 6 & 12th after surgery.

  5. Corneal aberrations over a 5-mm pupil

    Corneal aberrations will be evaluated as the root mean square (RMS) values derived from Zernike polynomial coefficients. Parameters will include total higher-order aberrations (HOA-RMS), spherical aberration, and coma. Measurements will be obtained using the MS-39 anterior segment optical coherence tomography (OCT) system (CSO, Florence, Italy)

    Measured: Day 1, week 1, months 1, 3, 6 & 12th after surgery

  6. Epithelial thickness

    Epithelial remodeling will be assessed using the MS-39 anterior segment optical coherence tomography (OCT) system (CSO, Florence, Italy). Epithelial thickness (µm) will be measured in five sectors-central, nasal, superior, inferior, and temporal.

    Measured: Day 1, week 1, months 1, 3, 6 & 12 after surgery

  7. Ocular Surface Disease Index (OSDI) score

    The Ocular Surface Disease Index (OSDI) questionnaire, validated for the Mexican population, will be administered to assess ocular discomfort, visual symptoms, and environmental triggers associated with dry eye disease.

    Measured: Week 1, months 1, 3, 6 & 12 after surgery

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted27 Jun 2024
  2. Study start1 Aug 2024
  3. Primary completion1 Mar 2027 (estimated)
  4. Study completion1 Mar 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Triple blind
Who is masked
Participant, Care provider, Outcomes assessor
Enrolment
80 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06477081
Sponsor's protocol ID
CI-017-2024
Status last verified
Jun 2026
First submitted
17 Jun 2024
Last updated
25 Jun 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Pradhan KR, Arba Mosquera S. SmartSight Correction of Compound Myopic Astigmatism Treatments With Preoperative Astigmatism > 1.00 Diopter Using the SCHWIND ATOS: A Retrospective Case Series. J Refract Surg. 2024 May;40(5):e328-e335. doi: 10.3928/1081597X-20240415-02. Epub 2024 May 1.

    PubMed 38717080
  • Igras E, Czarnota-Nowakowska B, O'Caoimh R. Comparison of the Clinical Effectiveness of Correcting Different Types of Astigmatism with Small Incision Lenticule Extraction. J Clin Med. 2023 Nov 6;12(21):6941. doi: 10.3390/jcm12216941.

    PubMed 37959406
  • Foo VHX, Liu YC, Ang M, Htoon HM, Ting DSJ, Mehta JS. Comparative Study of Primary SMILE, SMILE Enhancement, and Femtosecond Laser-Assisted LASIK on Higher Order Aberrations and Corneal Densitometry. J Refract Surg. 2024 May;40(5):e291-e303. doi: 10.3928/1081597X-20240314-01. Epub 2024 May 1.

    PubMed 38717083
  • Muleiro-Alvarez M, Vera-Duarte GR, Medina-Estrada EA, Ortiz-Morales G, Ramirez-Miranda A, Navas A, Graue-Wiechers EL, Graue-Hernandez EO, Kahuam-Lopez N. Keratorefractive lenticule extraction (KLEx) versus femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for the treatment of myopia and compound myopic astigmatism: study protocol of a randomised clinical trial in Mexico. BMJ Open. 2025 Dec 23;15(12):e097192. doi: 10.1136/bmjopen-2024-097192.

    PubMed 41436254

Questions about this trial

What is this clinical trial studying?

A study testing FS-LASIK procedure and KLEx in people with Myopia and Astigmatism, run by Instituto de Oftalmología Fundación Conde de Valenciana at 1 site in Mexico.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 25 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Mexico. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Uncorrected Visual Acuity (time frame: Day 1, week 1, months 1, 3, 6 & 12th after surgery.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06477081, which also lists 4 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Jun 2026.

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