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Clinical Trial Details — Status: Not yet recruiting

Administrative data

NCT number NCT05829980
Other study ID # CONvsWFO
Secondary ID
Status Not yet recruiting
Phase
First received
Last updated
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
Health authority
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
Accepts healthy volunteers
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

Study Design


Related Conditions & MeSH terms


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
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