Compare Corneal High Order Aberrations Before and After Stream Light Trans-PRK and Mechanical Photorefractive Keratectomy
Conditions
Brief summary
Compare corneal high order aberrations before and after stream light trans-PRK and mechanical photorefractive keratectomy including third order aberrations; Trefoil and coma aberrations and forth order aberrations; spherical aberrations
Detailed description
Laser technology has played an important role in promoting the development of ophthalmology, especially corneal refractive surgery.1 Trans-epithelial photorefractive keratectomy (Trans-PRK) has become a highly researched topic in recent years.2 Different epithelial debridement methods with PRK showed favorable results for the surgical treatment of low to moderate myopia3. In mechanical PRK (m-PRK), epithelial debridement is achieved using a blunt spatula, whereas in stream light trans-PRK (t-PRK), there after an excimer laser is used to ablate corneal stroma3. The Stream Light t-PRK is a safe and effective treatment option for the correction of low to moderate myopia.4 Many studies have shown that the corneal asphericity developed significantly after refractive surgeries and introduce higher-order aberrations (HOAs).2 The present study focused on three of the most clinically important HOAs; spherical, coma, and trefoil aberrations, both preoperative and postoperative were recorded from topography over the 6-mm-diameter central corneal zone using Pentacam.
Interventions
Laser keratectomy by EX500 excimer laser after removal of corneal epithelium either mannually or by laser ablation
Sponsors
Assiut University
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
20 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
* • Stable refraction for 1 year (refraction does not exceed 1D more than the last prescribed glasses). * Discontinuation of soft contact lens wears at least 1 week before examination. * Topography criteria: * Corneal thickness equal or more than 470 um * Symmetrical bow-tie * Back elevation not more than +12 * Normal Belin\\Ambrosio Enhanced ectasia display * Spherical equivalent not more than -6D.
Exclusion criteria
* • Previous ocular surgery * Concurrent ocular pathology; corneal scar, corneal dystrophy * Systemic disease; Uncontrolled diabetes, collagen disease * Post-operative complications; sub-epithelial haze.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Corneal high order aberrations measured before and after the intervention by corneal topography machine | 1 monthe after surgery | * Third order aberrations; Trefoil and coma aberrations * Forth order aberrations; spherical aberrations Trefoil, spherical and coma aberrations |
Countries
Egypt
Contacts
Primary ContactEsraa R Mokhtar, master
Backup ContactKhaled A Mohamed, MD
Outcome results
None listed