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

Q Value Customized Versus Wavefront Optimized Ablation in Femtosecond Laser-Assisted LASIK for Myopia and Myopic Astigmatism. A Contralateral Comparative Study

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.

Study Overview

• Status: Completed
• Conditions: Patients With Myopic Spherical Equivalent up to -12 Diopters
• Intervention / Treatment: Procedure: Femtosecond laser assisted LASIK eye surgery

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 Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Assiut, Egypt, 71516
    • Tiba Eye Center

Participation Criteria

Eligibility Criteria

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

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative Q value	Pentacam evaluation of post-LASIK Q value	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative corneal thickness at the pupillary center	Pentacam evaluation of post-LASIK pachymetry at the pupil center	6 months

Collaborators and Investigators

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

Publications and helpful links

General 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.
• Mostafa MM, Abdelmotaal H, Abdelazeem K, Goda I, Abdel-Radi M. Q-value customized versus wavefront-optimized ablation in femtosecond laser-assisted LASIK for myopia and myopic astigmatism: a prospective contralateral comparative study. Eye Vis (Lond). 2022 Nov 2;9(1):43. doi: 10.1186/s40662-022-00312-3.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2020
• Primary Completion (Actual): June 30, 2021
• Study Completion (Actual): June 30, 2021

Study Registration Dates

• First Submitted: February 1, 2021
• First Submitted That Met QC Criteria: February 1, 2021
• First Posted (Actual): February 4, 2021

Study Record Updates

• Last Update Posted (Actual): July 20, 2021
• Last Update Submitted That Met QC Criteria: July 19, 2021
• Last Verified: July 1, 2021

More Information

Terms related to this study

• Keywords: Femtosecond LASIK; Q value; Wave-front Optimized (WFO)
• Additional Relevant MeSH Terms: Eye Diseases; Refractive Errors; Myopia
• Other Study ID Numbers: CQLASIK

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No