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

NCT ID: NCT07203976

Last Updated: 2025-10-02

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Total Enrollment: 100 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2025-05-03
• Study Completion Date: 2026-05-31

Brief Summary

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.

Detailed Description

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)

Conditions

Photorefractive Keratectomy

Study Design

• Observational Model Type: OTHER
• Study Time Perspective: RETROSPECTIVE

Study Groups

Patients aged 18-40 years, myopia up to -6.00 D and astigmatism up to -3.00 D and Stable refraction

The visual and refractive outcomes of Stream Light Photorefractive keratectomy with fixed epithelial removal.

No interventions assigned to this group

Patients aged 18-40 years, myopia up to -6.00 D and astigmatism up to -3.00 D and Stable refraction

The visual and refractive outcomes of manual Photorefractive keratectomy with fixed epithelial removal.

No interventions assigned to this group

Eligibility Criteria

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.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 40 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Assiut University

OTHER

Sponsor Role: lead

Responsible Party

Menatallah Gamal Saleh

lecturer of ophthalmology

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Faculty of medicine, Assiut

Asyut, , Egypt

Countries

Egypt

References

3. Marshall, J., Trokel, S. L., Rothery, S., & Krueger, R. R. (2018). Refractive corneal surgery: The role of epithelial healing and biomechanics. Cornea, 37(7), 853-860.

Reference Type: BACKGROUND

Fantes FE, Hanna KD, Waring GO 3rd, Pouliquen Y, Thompson KP, Savoldelli M. Wound healing after excimer laser keratomileusis (photorefractive keratectomy) in monkeys. Arch Ophthalmol. 1990 May;108(5):665-75. doi: 10.1001/archopht.1990.01070070051034.

Reference Type: BACKGROUND

PMID: 2334323 (View on PubMed)

Other Identifiers

04-2025-300627

Identifier Type: -

Identifier Source: org_study_id