Contoura vs Wavefront Optimized Ablation

Astigmatism Clinical Trial

Official title:

Contoura Topography-guided Ablation Versus Wavefront-optimized Ablation for Correction of Astigmatism

Clinical Trial Details — Status: Not yet recruiting

Administrative data

• NCT number: NCT05829980
• Other study ID #: CONvsWFO
• Status: Not yet recruiting
• Start date: June 2023
• Est. completion date: April 2025

Study information

• Verified date: April 2023
• Source: Assiut University
• Contact: Mohamed S. Saad Abdallah, Professor
• Phone: 01001825024
• Email: mohsayedsaad[@]aun.edu.eg
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

To evaluate the efficacy, safety and accuracy of Contoura topography-guided LASIK & PRK in comparison to Wavefront optimized LASIK & PRK in virgin eyes with astigmatism.

Description:

In Upper Egypt, The second principal cause of blindness was uncorrected refractive errors accounting for 16% of sample population. It was reported that astigmatism (defined as cylinder power > 0.5 D) was the most common refractive errors in children and adults followed by hyperopia and myopia.

Laser vision correction has been established over the last 2 decades as a safe and effective intervention to treat refractive errors, being one of the main techniques practiced globally.

However, many subjects after LASIK had uncorrected distance visual acuity (UDVA) greater than 1.0, they complain about poor night vision, glare, and double vision. As studies have shown that every 1° deviation of the astigmatic axis could result in loss of correction of 3.3%. Even residual astigmatism less than 0.50D could have an actual impact on visual quality.

Excimer laser ablation used in the correction of refracted errors especially astigmatism may reduce quality of vision, and that is attributed to the induced optical aberrations. The most prevalent of these optical aberrations is the spherical aberration.

Among multiple sophisticated profiles that developed to optimize visual outcomes, wavefront optimized profile which compensate for corneal curvature to reduce spherical aberration.

The topographic guided profiles which consider the shape of the anterior corneal surface. Contoura topography guided ablation corrects astigmatic power and axis to create a more uniform, aberration-free cornea.

Treating astigmatism can be challenging as the conventional patterns of Excimer laser treatment of astigmatism is known to be less predictable than that of spherical refractive errors.

Recruitment information / eligibility

• Status: Not yet recruiting
• Enrollment: 128
• Est. completion date: April 2025
• Est. primary completion date: December 2024
• Gender: All
• Age group: 18 Years to 45 Years

Eligibility

Inclusion Criteria:

• Astigmatism (up to 5.0 diopters) or less.

• Central corneal thickness (CCT) of 500 microns or more

• Estimated Residual stromal bed thickness (RSB) of 280 microns or more

• Subject has provided written informed consent

Exclusion Criteria:

• Keratoconus

• Abnormal topography

• previous ocular trauma or eye surgery

• pre-existing diseases of the vitreous, macula, or optic nerve that can affect visual outcome

• patients with uveitis and anterior segment pathology

• patients with corneal pathology or Severe dry eye

• pregnancy or breast-feeding females

• uncontrolled vascular or autoimmune disease

Related Conditions & MeSH terms

• Astigmatism

Intervention

Procedure:
• Laser assisted in-situ keratomileusis
Laser-Assisted In Situ Keratomileusis is a procedure that permanently changes the shape of the cornea using an excimer laser and the mechanical microkeratome (a blade device) used to cut a flap in the cornea.
• Photorefractive keratectomy
Photorefractive keratectomy is a laser refractive procedure used to ablate the corneal stroma to correct refractive errors without cutting flap

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
Hebatallah MT Abdelmoniem

References & Publications (10)

Bailey MD, Zadnik K. Outcomes of LASIK for myopia with FDA-approved lasers. Cornea. 2007 Apr;26(3):246-54. doi: 10.1097/ICO.0b013e318033dbf0. — View Citation

Canones-Zafra R, Katsanos A, Garcia-Gonzalez M, Gros-Otero J, Teus MA. Femtosecond LASIK for the correction of low and high myopic astigmatism. Int Ophthalmol. 2022 Jan;42(1):73-80. doi: 10.1007/s10792-021-02001-x. Epub 2021 Aug 9. — View Citation

Gatinel D, Malet J, Hoang-Xuan T, Azar DT. Analysis of customized corneal ablations: theoretical limitations of increasing negative asphericity. Invest Ophthalmol Vis Sci. 2002 Apr;43(4):941-8. — View Citation

Hashemi H, Fotouhi A, Yekta A, Pakzad R, Ostadimoghaddam H, Khabazkhoob M. Global and regional estimates of prevalence of refractive errors: Systematic review and meta-analysis. J Curr Ophthalmol. 2017 Sep 27;30(1):3-22. doi: 10.1016/j.joco.2017.08.009. eCollection 2018 Mar. — View Citation

Kanellopoulos AJ. Topography-modified refraction (TMR): adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK. Clin Ophthalmol. 2016 Nov 3;10:2213-2221. doi: 10.2147/OPTH.S122345. eCollection 2016. — View Citation

Lin Y, Su HJ, Yuan MZ, Zhang Y. Vector analysis of Contoura Vision for the correction of myopia and myopic astigmatism. Int J Ophthalmol. 2022 Jun 18;15(6):983-989. doi: 10.18240/ijo.2022.06.17. eCollection 2022. — View Citation

Lukenda A, Martinovic ZK, Kalauz M. Excimer laser correction of hyperopia, hyperopic and mixed astigmatism: past, present, and future. Acta Clin Croat. 2012 Jun;51(2):299-304. — View Citation

Motwani M. The use of WaveLight(R) Contoura to create a uniform cornea: the LYRA Protocol. Part 3: the results of 50 treated eyes. Clin Ophthalmol. 2017 May 16;11:915-921. doi: 10.2147/OPTH.S133841. eCollection 2017. — View Citation

Mousa A, Courtright P, Kazanjian A, Bassett K. Prevalence of visual impairment and blindness in Upper Egypt: a gender-based perspective. Ophthalmic Epidemiol. 2014 Jun;21(3):190-6. doi: 10.3109/09286586.2014.906629. Epub 2014 Apr 18. — View Citation

Villegas EA, Alcon E, Artal P. Minimum amount of astigmatism that should be corrected. J Cataract Refract Surg. 2014 Jan;40(1):13-9. doi: 10.1016/j.jcrs.2013.09.010. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in Postoperative UDVA compared to preoperative CDVA (in LogMAR)	UCVA 3 month after surgery compared to baseline preoperative CDVA	3 month
Primary	Number of lines of preoperative CDVA compared to postoperative	Change in lines of CDVA from baseline preoperative to 3 month postoperative (in LogMAR)	3 month
Primary	Amount of Residual Astigmatism postoperatively (in Diopters)	residual astigmatism 3 month postoperatively	3 month
Primary	Postoperative mean spherical equivalent MSE compared to Preoperative MSE (in Diopters)	changes in mean spherical equivalent baseline preoperative to 3 month postoperative	3 month
Secondary	Change in Contrast sensitivity test		3 month
Secondary	Amount of High order aberrations	(Spherical aberration, trefoil, vertical & horizontal coma)	3 month