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NCT Number: NCT07203976

Visual and Refractive Outcomes Following Stream Light Photorefractive Keratectomy (55μm Epithelial Removal) Versus Conventional Photorefractive Keratectomy

Photorefractive keratectomy (PRK) is a well-established corneal refractive surgery that involves epithelial removal followed by stromal ablation to correct myopia, hyperopia, and astigmatism. The method of epithelial removal in PRK significantly impacts healing, pain levels, and visual outcomes.

Trans-epithelial PRK (StreamLight) performed on the EX500 excimer laser platform removes the epithelium and reshapes the corneal stroma in a single laser-guided step, potentially reducing tissue manipulation and enhancing epithelial healing. In contrast, manual epithelial removal PRK involves mechanical debridement, with epithelial removal depth being manually controlled. The variability of epithelial thickness in StreamLight PRK may influence visual outcomes, whereas in manual PRK, a fixed epithelial removal depth of 55 microns provides a standardized approach.

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Key information

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Faculty of medicine, Assiut

Asyut, Egypt

About this study

This study aimed to compare the visual and refractive outcomes of StreamLight PRK versus manual PRK with fixed epithelial removal.

Type of the study: Retrospective cross-sectional study

  • Study Setting: Alforsan Eye Centre
  • Study subjects:

a. Inclusion criteria:

  • Patients aged 18-40 years.
  • Myopia up to -6.00 D and astigmatism up to -3.00 D.
  • Stable refraction for at least one year.
  • No history of ocular surgery or corneal pathology. b. Exclusion criteria:
  • Presence of keratoconus or suspected corneal ectasia.
  • Severe dry eye disease or significant ocular surface disease.
  • History of autoimmune disease or systemic conditions affecting wound healing.
  • Prior herpetic eye disease. c. Sample Size Calculation: A sample size calculation will be performed to ensure adequate statistical power. Anticipated enrollment: [e.g., 50 eyes per group] based on previous PRK outcome studies (Marshall et al., 2018).
  • Study tools (in detail, e.g., lab methods, instruments,steps, chemicals, …):
  • Alcon Wavelight EX500 excimer laser (Alcon Laboratories, Fort Worth, TX, USA)
  • Wavelight Oculyzer II Am Wolfsmantel 5, Erlangen, Germany
  • Autorefractor KR-8900 (Topcon, Tokyo, Japan)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients aged 18-40 years.
  • Myopia up to -6.00 D and astigmatism up to -3.00 D.
  • Stable refraction for at least one year.
  • No history of ocular surgery or corneal pathology.

Exclusion criteria

  • Presence of keratoconus or suspected corneal ectasia.
  • Severe dry eye disease or significant ocular surface disease.
  • History of autoimmune disease or systemic conditions affecting wound healing.
  • Prior herpetic eye disease.

Treatment and study plan

Primary outcomes

  1. Post operative distant uncorrected visual acuity

    Time frame: 1 year

    using snellen chart

Secondary outcomes

  1. Post operative spherical equivalent of refractive error

    Time frame: 1 year

    using autorefractometer

Sponsors and collaborators

Lead sponsor

Assiut University

Other

Registry information

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Oct 2, 2025
Registry last updated
Oct 2, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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