Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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UNKNOWN
128 participants
OBSERVATIONAL
2023-06-30
2025-04-30
Brief Summary
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Detailed Description
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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.
Conditions
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Study Design
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COHORT
PROSPECTIVE
Study Groups
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Group A
Contoura topography-guided LASIK
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.
Group B
Contoura topography-guided PRK
Photorefractive keratectomy
Photorefractive keratectomy is a laser refractive procedure used to ablate the corneal stroma to correct refractive errors without cutting flap
Group C
Wavefront-optimized LASIK
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.
Group D
Wavefront-optimized PRK
Photorefractive keratectomy
Photorefractive keratectomy is a laser refractive procedure used to ablate the corneal stroma to correct refractive errors without cutting flap
Interventions
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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
Other Intervention Names
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Eligibility Criteria
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Inclusion Criteria
* 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
* 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
18 Years
45 Years
ALL
No
Sponsors
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Hebatallah MT Abdelmoniem
OTHER
Responsible Party
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Hebatallah MT Abdelmoniem
Assistant Lecturer
Principal Investigators
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Mohamed A. Sayed, Ass. Prof.
Role: STUDY_CHAIR
Assiut University
Central Contacts
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References
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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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Other Identifiers
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CONvsWFO
Identifier Type: -
Identifier Source: org_study_id
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