Characterization of the Corneal Biomechanics of Patients Treated by Corneal Lenticule Extraction for Advanced Refractive Correction (CLEAR) to Correct Myopia

NCT ID: NCT04817592

Last Updated: 2025-09-19

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Total Enrollment

100 participants

Study Classification

OBSERVATIONAL

Study Start Date

2026-06-01

Study Completion Date

2027-12-31

Brief Summary

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This study aims to perform biomechanical tests on extracted CLEAR lenticles that are routinely discarded after surgery. The investigators also aim to perform Brillouin microscopy to get an in-vivo assessment of the patient's cornea preoperatively and to correlate this data with the postoperative characterization of the extracted corneal lenticule. The characterization will be done with established biomechanical and morphologic tests.

Detailed Description

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Refractive surgery techniques such as laser in situ keratomileusis (LASIK), corneal lenticule extraction (SMILE/CLEAR) and photorefractive keratectomy (PRK) are becoming increasingly popular among myopic patients. With current surgical planning tools, there is a reported 10-15 % chance of over/under correction, in particular with higher corrections. The biggest factor that leads to this discrepancy is the "one size fits all" approach. Patient specific characteristics of the eye such as the corneal material properties, are not considered in the surgical planning. This information is also essential for diagnosis and treatment of pathologies like keratoconus. New diagnostics devices based on e. g. Brillouin scattering are now introduced on the market, with the aim to provide an in-vivo quantification of the biomechanical tissue properties. However, the relationship between the Brillouin measurement and the biomechanical properties of the cornea is not fully understood yet. The investigators aim for determining an improved relationship between the optical Brillouin measurement performed in-vivo preoperatively and classical destructive biomechanical testing of the extracted corneal lenticule after the surgery. This lenticule is currently discarded after surgery.

The purpose of the study is to investigate the exact relationship between the classically determined material properties (by stress-/strain measurements) and optically obtained data by Brillouin scattering, which are collected during pre-op investigations. A precise characterization and relation between both measurements will allow clinicians to better predict surgical parameters and perform better refractive interventions. This information will also inform clinicians on the mechanical status of the cornea of patients suffering from subclinical keratoconus.

Conditions

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Myopia

Study Design

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Observational Model Type

COHORT

Study Time Perspective

PROSPECTIVE

Study Groups

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Age1(20-25)

The groups are divided as per age

Corneal lenticule extraction for advanced refractive correction (CLEAR)

Intervention Type PROCEDURE

Routinely conducted procedure for correction of Myopia

Age2(25-30)

Corneal lenticule extraction for advanced refractive correction (CLEAR)

Intervention Type PROCEDURE

Routinely conducted procedure for correction of Myopia

Age3(30-35)

Corneal lenticule extraction for advanced refractive correction (CLEAR)

Intervention Type PROCEDURE

Routinely conducted procedure for correction of Myopia

Age4(35-40)

Corneal lenticule extraction for advanced refractive correction (CLEAR)

Intervention Type PROCEDURE

Routinely conducted procedure for correction of Myopia

Age5(40-45)

Corneal lenticule extraction for advanced refractive correction (CLEAR)

Intervention Type PROCEDURE

Routinely conducted procedure for correction of Myopia

Interventions

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Corneal lenticule extraction for advanced refractive correction (CLEAR)

Routinely conducted procedure for correction of Myopia

Intervention Type PROCEDURE

Other Intervention Names

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SMILE

Eligibility Criteria

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Inclusion Criteria

* Patients scheduled for CLEAR procedures for myopia (range: \>-3D with an astigmatism \<0.25D) in the age group 20-50 years.
* Willing and able to return for scheduled follow-up examinations
* Able to provide written informed consent and follow study instructions in English or German

Exclusion Criteria

* Irregular corneal topo-/tomography (Asymmetry \>1.0D within the inner 5mm)
* Previous intraocular or corneal surgery of any kind in the eye to be treated, including any type of surgery for either refractive or therapeutic purposes.
* History of steroid-responsive rise in intraocular pressure, glaucoma, or preoperative intraocular pressure (IOP) \> 21 mmHg in either eye.
* History of diabetes, diagnosed autoimmune disease, connective tissue disease or clinically significant atopic syndrome.
Minimum Eligible Age

20 Years

Maximum Eligible Age

50 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Bern

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Philippe Büchler, Prof. Dr.

Role: PRINCIPAL_INVESTIGATOR

University of Bern

Locations

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IROC AG

Zurich, , Switzerland

Site Status

Countries

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Switzerland

Central Contacts

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Philippe Büchler, Prof. Dr.

Role: CONTACT

+41 31 684 14 10

Facility Contacts

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Theo Seiler, Priv.-Doz. Dr. med.

Role: primary

Other Identifiers

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Basec Nr 2021-001-45

Identifier Type: -

Identifier Source: org_study_id

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