Q Value Customized Versus Wavefront Optimized Ablation in Femtosecond Laser-Assisted LASIK

• ClinicalTrials.gov Identifier: NCT04738903
• Recruitment Status: Completed
• First Posted: February 4, 2021
• Last Update Posted: July 20, 2021
• Sponsor: Assiut University
• Information provided by (Responsible Party): Mahmoud Abdel-Radi, Assiut University

Study Description

Brief Summary:

Corneal asphericity is expressed numerically as the "Q-value". A minus value means that corneal curvature flattens towards the periphery and the cornea is prolate in shape, but when the curvature steepens towards the periphery, the cornea is oblate in shape and has a positive Q-value.

The current study evaluates the effect of LASIK eye surgery on corneal asphericity by comparing 2 software treatment platforms; the Q value customized ablation versus the conventional Wave-front optimized ablation in a fellow eye study pattern.

Condition or disease	Intervention/treatment	Phase
Patients With Myopic Spherical Equivalent up to -12 Diopters	Procedure: Femtosecond laser assisted LASIK eye surgery	Not Applicable

Detailed Description:

The standard excimer laser correction of myopia is associated with decreased visual quality in the form of a decrease in contrast sensitivity and night vision. This degradation of the visual quality is attributed to changes in the corneal asphericity that increase the high order aberrations (HOAs), such as spherical aberrations because it leads to shifting of the corneal asphericity towards the oblate shape.

The wavefront-optimized (WFO) profile avoids the creation of new HOAs, but it is not able to treat those which are already present pre-operatively.

The Q-adjusted treatments correct the sphero-cylindrical refractive errors and try to maintain the corneal asphericity at the same time, but like the WFO ablation profiles, it is limited to correcting the spherical aberrations and not the non-rotational symmetric HOAs.

Some studies compared Lasers of two different platforms on contralateral eyes of the same patient in order to minimize inter-patient differences such as corneal wound healing and corneal biomechanics. By exclusion of these inter-patient differences, a more accurate judgment on the outcomes can be achieved.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 40 participants
• Allocation: Non-Randomized
• Intervention Model: Parallel Assignment
• Masking: Single (Outcomes Assessor)
• Primary Purpose: Treatment
• Official Title: Q Value Customized Versus Wavefront Optimized Ablation in Femtosecond Laser-Assisted LASIK for Myopia and Myopic Astigmatism. A Contralateral Comparative Study
• Actual Study Start Date: June 1, 2020
• Actual Primary Completion Date: June 30, 2021
• Actual Study Completion Date: June 30, 2021

Arms and Interventions

Arm	Intervention/treatment
Active Comparator: Custom Q treatment group; For every patient, the eye with the greater myopic spherical equivalent (SE) will be assigned for the Custom-Q treatment group.	Procedure: Femtosecond laser assisted LASIK eye surgery; FS-LASIK eye surgery includes corneal flap creation with femtosecond laser using the Femtosecond laser WaveLight FS200 followed by excimer laser vision correction of the patient's refractive error using excimer laser WaveLight EX500.
Active Comparator: Wave-front optimized (WFO) group; For every patient, the other eye with the lesser myopic SE will be assigned for the WFO treatment group	Procedure: Femtosecond laser assisted LASIK eye surgery; FS-LASIK eye surgery includes corneal flap creation with femtosecond laser using the Femtosecond laser WaveLight FS200 followed by excimer laser vision correction of the patient's refractive error using excimer laser WaveLight EX500.

Outcome Measures

Primary Outcome Measures :

1. Postoperative Q value [ Time Frame: 6 months ]
   Pentacam evaluation of post-LASIK Q value

Secondary Outcome Measures :

1. Postoperative corneal thickness at the pupillary center [ Time Frame: 6 months ]
   Pentacam evaluation of post-LASIK pachymetry at the pupil center

Eligibility Criteria

• Ages Eligible for Study: 18 Years and older (Adult, Older Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria: Candidates for Laser vision correction (LVC) with

1. Myopic Spherical Equivalent up to -12 diopters.
2. Myopic astigmatism up to -6 diopters.
3. Corneal thinnest location ≥ 500 um 4- Residual stromal bed ≥ 300 um.

Exclusion Criteria:

1. Patients not candidates for LVC.
2. Hyperopic patients or mixed astigmatism.
3. Systemic disease that contraindicates LVC.
4. Intra- or post-operative complications. 5- Previous corneal surgery

Contacts and Locations

Locations

Egypt

TIBA eye center

Assiut, Egypt, 71516

Sponsors and Collaborators

Assiut University

Investigators

• Principal Investigator: Mahmoud Abdel-Radi, MD; Assiut University

More Information

Publications:

Piao J, Li YJ, Whang WJ, Choi M, Kang MJ, Lee JH, Yoon G, Joo CK. Comparative evaluation of visual outcomes and corneal asphericity after laser-assisted in situ keratomileusis with the six-dimension Amaris excimer laser system. PLoS One. 2017 Feb 10;12(2):e0171851. doi: 10.1371/journal.pone.0171851. eCollection 2017.

• Responsible Party: Mahmoud Abdel-Radi, Principal Investigator, Assiut University
• ClinicalTrials.gov Identifier: NCT04738903
• Other Study ID Numbers: CQLASIK
• First Posted: February 4, 2021
• Last Update Posted: July 20, 2021
• Last Verified: July 2021

Individual Participant Data (IPD) Sharing Statement:

• Plan to Share IPD: No

• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No

Keywords provided by Mahmoud Abdel-Radi, Assiut University:

Femtosecond LASIK; Q value; Wave-front Optimized (WFO)

Additional relevant MeSH terms:

Myopia; Refractive Errors; Eye Diseases