Corneal High Order Aberrations After Stream Light and Mechanical Photorefractive Keratectomy
Study Details
Study Description
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
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
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.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Mechanical photorefractive keratectomy Laser photorefractive keratecyomy by Ex500 excimer laser after mannual removal of corneal epithelium |
Other: Photorefractive keratectomy
Laser keratectomy by EX500 excimer laser after removal of corneal epithelium either mannually or by laser ablation
|
| Stream light trans-PRK Laser photorefractive keratectomy by Ex500 excimer laser after removal of corneal epithelium by stream-light laser technique |
Other: Photorefractive keratectomy
Laser keratectomy by EX500 excimer laser after removal of corneal epithelium either mannually or by laser ablation
|
Outcome Measures
Primary Outcome Measures
- 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
Eligibility Criteria
Criteria
Inclusion Criteria:
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• Stable refraction for 1 year (refraction does not exceed 1D more than the last prescribed glasses).
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Discontinuation of soft contact lens wears at least 1 week before examination.
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Topography criteria:
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Corneal thickness equal or more than 470 um
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Symmetrical bow-tie
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Back elevation not more than +12
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Normal Belin\Ambrosio Enhanced ectasia display
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Spherical equivalent not more than -6D.
Exclusion Criteria:
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• Previous ocular surgery
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Concurrent ocular pathology; corneal scar, corneal dystrophy
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Systemic disease; Uncontrolled diabetes, collagen disease
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Post-operative complications; sub-epithelial haze.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Assiut university faculty of medicine | Assiut | Assiut University | Egypt | 71515 |
Sponsors and Collaborators
- Assiut University
Investigators
None specified.Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- 1799