Clinical trial NCT04738903: Q Value Customized Versus Wavefront Optimized Ablation in Femtosecond Laser-Assisted LASIK
Official title: Q Value Customized Versus Wavefront Optimized Ablation in Femtosecond Laser-Assisted LASIK for Myopia and Myopic Astigmatism. A Contralateral Comparative Study
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Patients With Myopic Spherical Equivalent up to -12 Diopters
Keywords: Femtosecond LASIK
Q value
Wave-front Optimized (WFO)
Lead sponsor: Assiut University
Sponsor class: OTHER
First posted: 2021-02-04
Enrollment: 40
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

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.

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.

Eligibility 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

Primary outcomes:
measure: Postoperative Q value
timeFrame: 6 months
Secondary outcomes:
measure: Postoperative corneal thickness at the pupillary center
timeFrame: 6 months
Other outcomes:
Locations:
city: Assiut
country: Egypt
facility: TIBA eye center
Study officials:
affiliation: Assiut University
name: Mahmoud Abdel-Radi, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.
citation: 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.