Photorefractive KeratectomyNCT07203976
Visual and Refractive Outcomes Following Stream Light Photorefractive Keratectomy (55μm Epithelial Removal) Versus Conventional Photorefractive Keratectomy
An observational study of Photorefractive Keratectomy, run by Assiut University at 1 site in Egypt.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 40 years
- Conditions the study is for
- Photorefractive Keratectomy
- How many people
- 100 participants
- Where
- 1 siteEgypt
- Study dates
- 3 May 2025to Sep 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- No healthy volunteers
- Adult
Study population: Patients aged 18-40 years with myopia up to -6.00 D and astigmatism up to -3.00 D and Stable refraction for at least one year.
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
About this study
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.
Read the 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:
- 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
- Keywords
- stream light photorefractive keratectomy, conventional photorefractive keratectomy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| 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. | |
| 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Post operative distant uncorrected visual acuity
using snellen chart
Measured: 1 year
Secondary outcomes (1)
Post operative spherical equivalent of refractive error
using autorefractometer
Measured: 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Oct 2025
- Study start3 May 2025
- Primary completionSep 2027 (estimated)
- Study completionSep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Photorefractive KeratectomyStudies of the same condition, open and under way.
- More trials run by Assiut UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Retrospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assiut University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Menatallah Gamal Saleh, Assiut University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07203976
- Sponsor's protocol ID
- 04-2025-300627
- Status last verified
- Nov 2026
- First submitted
- 24 Sep 2025
- Last updated
- 3 Nov 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
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.
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.
PubMed 2334323
Study at a glance
From the registry record, last updated by the sponsor on 3 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Visual and Refractive Outcomes Following Stream Light Photorefractive Keratectomy (55μm Epithelial Removal) Versus Conventional Photorefractive Keratectomy
- ClinicalTrials.gov ID
- NCT07203976
- Acronym / sponsor ID
- 04-2025-300627
- Conditions
- Photorefractive Keratectomy
- Keywords
- stream light photorefractive keratectomy, conventional photorefractive keratectomy
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Assiut UniversityUniversity, hospital or other
- Study start
- 3 May 2025 (actual)
- Primary completion
- Sep 2027 (estimated)
- Study completion
- Sep 2027 (estimated)
- First posted
- 2 Oct 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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:
- 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)
Study design
- Observational model
- Other
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 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. |
| 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. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
- Study population
- Patients aged 18-40 years with myopia up to -6.00 D and astigmatism up to -3.00 D and Stable refraction for at least one year.
Key inclusion criteria (4 listed)
- 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.
Key exclusion criteria (4 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Post operative distant uncorrected visual acuity
Time frame: 1 year
using snellen chart
1 secondary outcome
Post operative spherical equivalent of refractive error
Time frame: 1 year
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Nov 2026.
- Background3. 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.
- Background: PubMed 2334323Fantes 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.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Photorefractive Keratectomy, run by Assiut University at 1 site in Egypt.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 3 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Post operative distant uncorrected visual acuity (time frame: 1 year). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07203976, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Nov 2026.