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MyopiaNCT02540785

Early Changes Between Lenticule Extraction and Small-Incision Lenticule Extraction

A study testing lenticule extraction and small-incision lenticule extraction in people with Myopia and Astigmatism, run by Sun Yat-sen University.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The aim is to evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE) procedures. Read more about this study

Who is it for?
Ages 18 to 25 yearsHealthy volunteers can take part
Conditions the study is for
Myopia, Astigmatism
What is being tested?
lenticule extraction and small-incision lenticule extraction
Type of treatment
Surgery or procedure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
41 participants
Where
No sites listed yet
Study dates
Apr 2014to Dec 2014
Phase
Interventional
Are there results?
None posted in the registry

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 18 to 25 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • minimum age of 18 years(range from 18 year to 25 years); corneal thickness 500 μm with calculated residual stromal bed after treatment greater than 300 μm; preoperative spherical equivalent refraction between
  • 2.00 diopter (D) and -6.50 D; preoperative cylindrical equivalent refraction between -0.25 D and -1.50 D; preoperative corneal curvature from 41.0 D to 46.0 D with a regular topographic pattern, verified with an Atlas topographer; monocular best corrected visual acuity of 20/20 or better and stable refractive error (less than 0.5 D change) for 24 months before surgery

Who cannot join

  • systemic disease that contraindicated the surgery (such as diabetes, glaucoma and systemic collagen vascular disease); corneal abnormality or disease; a history of tear supplement usage or contact lens wear during the past year

About this study

Official title: Comparison of Early Changes in Ocular Surface and Inflammatory Mediators Between Lenticule Extraction and Small-Incision Lenticule Extraction

The aim is to evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE) procedures.

Read the detailed description

The use of femtosecond (FS) laser has become one of the most significant technological advancements in refractive surgery. A breakthrough FS laser-assisted myopic and myopic astigmatic correction procedure can now be performed using a prototype femtosecond system. This first all-in-one FS-laser system was designed to perform the refractive lenticule extraction (ReLEx) procedures, femtosecond lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE). In FLEx, a corneal flap is created by the FS laser (similar to LASIK) and lifted, allowing lenticule removal. For SMILE, a truly without flap procedure, only a small-2-4mm- incision is made, through which the lenticule is removed.

Ocular surface disruption during corneal refractive surgery is commonly considered to be closely related to the development of dry eye. Multiple etiologies contribute to this ocular surface disruption, including the flap creation and stromal ablation involved in previous refractive surgery techniques. Corneal nerve damage has been considered the main cause of dry eye, due to disrupted afferent sensory nerves, reduced blink reflex, and increased tear evaporation leading to tear film instability. In addition, postoperative inflammatory mediator fluctuations are also a key factor related to ocular surface damage. Extensive research has described the effects of cytokines, chemokines and growth factors in modulating corneal wound healing, cell migration, and apoptosis on the ocular surface after refractive surgery.

For both FLEx and SMILE, stromal ablation has been replaced by refractive lenticule removal. In terms of corneal flap formation, FLEx still requires an epithelial-stromal flap, while SMILE employs only a small incision to extract the lenticule. Hence, the investigators hypothesize that SMILE will have less effect on patients' ocular surface markers and inflammatory mediators, compared to FLEx. In support of this hypothesis, previous studies have reported that more damage to the sub-basal nerve plexus of the cornea and more changes in ocular surface evaluations were found after FLEx than after SMILE. In this study, the investigators have focused on postoperative changes to tear inflammatory mediators and the relationship of FLEx and SMILE to dry eye.

Conditions
Myopia, Astigmatism
Being tested
lenticule extraction, small-incision lenticule extraction
Keywords
Refractive Surgical Procedures, small-incision lenticule extraction, lenticule extraction, inflammatory mediators
Medical subject headings
Myopia, Astigmatism

What participants receive

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

  • lenticule extractionProcedure or surgery

    Also called 0.3% tobramycin/dexamethasone (TobraDex, Alcon), 0.5% levofloxacin (Cravit, Santen), sodium hyaluronate (HYCOSAN,URSAPHARM Arzneimittel GmbH)

    Four femtosecond incisions were created in succession: the posterior surface of the refractive lenticule (spiral in), the lenticule border, the anterior surface of the refractive lenticule (spiral out), and the corneal flap in the superior region. After the suction was released, the flap was opened using a thin, blunt spatula and the free refractive lenticule was subsequently grasped with a forceps and extracted, after which the flap was repositioned carefully

  • small-incision lenticule extractionProcedure or surgery

    Also called 0.3% tobramycin/dexamethasone (TobraDex, Alcon), 0.5% levofloxacin (Cravit, Santen), sodium hyaluronate (HYCOSAN,URSAPHARM Arzneimittel GmbH)

    Four femtosecond incisions were created in succession: the posterior surface of the refractive lenticule (spiral in), the lenticule border, the anterior surface of the refractive lenticule (spiral out), make a small incision

Study groups in NCT02540785
Study groupRoleWhat they receive
lenticule extractionExperimentalThe patients in this group chose to receive the lenticule extraction surgery.
Receives: Procedure: lenticule extraction
small-incision lenticule extractionExperimentalThe patients in this group chose to receive the small-incision lenticule extraction surgery.
Receives: Procedure: small-incision lenticule extraction

What is being measured

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

  1. scale of Schirmer I test

    Measured: up to 1month after surgery

  2. scale of corneal fluorescein staining

    Measured: up to 1month after surgery

  3. scale of noninvasive tear breakup time

    Measured: up to 1month after surgery

  4. questionnaire of ocular surface disease index

    Measured: up to 1month after surgery

  5. scale of central corneal sensitivity

    Measured: up to 1month after surgery

  6. scale of tear meniscus height

    Measured: up to 1month after surgery

  7. concentration of Interleukin-1α

    Measured: up to 1month after surgery

  8. concentration of tumor necrosis factor-α

    Measured: up to 1month after surgery

  9. concentration of nerve growth factor

    Measured: up to 1month after surgery

  10. concentration of interferon-γ

    Measured: up to 1month after surgery

  11. concentration of transforming growth factor-β1

    Measured: up to 1month after surgery

  12. concentration of matrix metalloproteinase-9

    Measured: up to 1month after surgery

Secondary outcomes (1)

  1. Correlation Between Inflammatory Mediators and Ocular Surface Changes

    Measured: up to 1month 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 posted4 Sep 2015 (estimated)
  2. Study startApr 2014
  3. Primary completionDec 2014
  4. Study completionDec 2014

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
Non-randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
41 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT02540785
Sponsor's protocol ID
2014-005
Status last verified
Nov 2016
First submitted
31 Aug 2015
Last updated
28 Nov 2016
Results posted
No
Data monitoring committee
No

Publications

  • Zhang C, Ding H, He M, Liu L, Liu L, Li G, Niu B, Zhong X. Comparison of Early Changes in Ocular Surface and Inflammatory Mediators between Femtosecond Lenticule Extraction and Small-Incision Lenticule Extraction. PLoS One. 2016 Mar 3;11(3):e0149503. doi: 10.1371/journal.pone.0149503. eCollection 2016.

    PubMed 26937680

Questions about this trial

What is this clinical trial studying?

A study testing lenticule extraction and small-incision lenticule extraction in people with Myopia and Astigmatism, run by Sun Yat-sen University.

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 2 inclusion and 1 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: finished, as of the sponsor's last update on 28 Nov 2016. Status can change between updates, so confirm with the study contact before making plans.

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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

scale of Schirmer I test (time frame: up to 1month after surgery). The study lists 12 primary outcomes in all. 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 NCT02540785, which also lists 1 linked publication.

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 28 Nov 2016.

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Clinical Trial NCT02540785 | AzTrials