Contoura vs Wavefront Optimized Ablation
- Conditions
- Astigmatism
- Interventions
- Procedure: Laser assisted in-situ keratomileusisProcedure: Photorefractive keratectomy
- Registration Number
- NCT05829980
- Lead Sponsor
- Hebatallah MT Abdelmoniem
- Brief 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.
- Detailed 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 & Eligibility
- Status
- NOT_YET_RECRUITING
- Sex
- All
- Target Recruitment
- 128
- 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
- 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
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Arm && Interventions
Group Intervention Description Group A Laser assisted in-situ keratomileusis Contoura topography-guided LASIK Group C Laser assisted in-situ keratomileusis Wavefront-optimized LASIK Group D Photorefractive keratectomy Wavefront-optimized PRK Group B Photorefractive keratectomy Contoura topography-guided PRK
- Primary Outcome Measures
Name Time Method Amount of Residual Astigmatism postoperatively (in Diopters) 3 month residual astigmatism 3 month postoperatively
Number of lines of preoperative CDVA compared to postoperative 3 month Change in lines of CDVA from baseline preoperative to 3 month postoperative (in LogMAR)
Postoperative mean spherical equivalent MSE compared to Preoperative MSE (in Diopters) 3 month changes in mean spherical equivalent baseline preoperative to 3 month postoperative
Change in Postoperative UDVA compared to preoperative CDVA (in LogMAR) 3 month UCVA 3 month after surgery compared to baseline preoperative CDVA
- Secondary Outcome Measures
Name Time Method Amount of High order aberrations 3 month (Spherical aberration, trefoil, vertical \& horizontal coma)
Change in Contrast sensitivity test 3 month