Corneal High Order Aberrations After Stream Light and Mechanical Photorefractive Keratectomy

Assiut University

Status: Enrolling

Conditions: Compare Corneal High Order Aberrations Before and After Stream Light Trans-PRK and Mechanical Photorefractive Keratectomy

Treatments: Other: Photorefractive keratectomy

Study type: Observational

Funder types: Other

Identifiers

NCT06110286

1799

Details and patient eligibility

About

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

Full 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.

Enrollment: 60 estimated patients

Sex: All

Ages: 20 to 40 years old

Volunteers: No Healthy Volunteers

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.

Trial design

60 participants in 2 patient groups

Mechanical photorefractive keratectomy

Description:

Laser photorefractive keratecyomy by Ex500 excimer laser after mannual removal of corneal epithelium

Treatment:

Other: Photorefractive keratectomy

Stream light trans-PRK

Description:

Laser photorefractive keratectomy by Ex500 excimer laser after removal of corneal epithelium by stream-light laser technique

Treatment:

Other: Photorefractive keratectomy