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Outcomes of a New Trans-epithelial Photorefractive Keratectomy (Streamlight PRK) Compared to Conventional PRK Procedures

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ClinicalTrials.gov Identifier: NCT04710082
Recruitment Status : Completed
First Posted : January 14, 2021
Last Update Posted : July 20, 2021
Sponsor:
Information provided by (Responsible Party):
Mahmoud Abdel-Radi, Assiut University

Study Description
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Brief Summary:
Photorefractive keratectomy (PRK) involves mechanical or alcohol assisted debridement of the epithelium that leads to potential basement membrane (BM) injury ,with resultant more significant haze and pain compared to laser assisted epithelial removal known as 2 step trans-epithelial PRK (PTK-PRK). Our study is focusing on comparing the outcomes of the conventional 2 step trans-epithelial PTK-PRK to the new single step trans-epithelial PRK (StreamLight PRK, Alcon lab, TX, USA).

Condition or disease Intervention/treatment Phase
Myopia ≤ -6 Diopters or Myopic Astigmatism ≤ -4 Diopters Procedure: Photorefractive keratectomy (PRK) Not Applicable

Detailed Description:

Photorefractive keratectomy (PRK) is nowadays one of the commonest refractive procedures in laser vision correction (LVC). PRK differs from laser in situ keratomileusis (LASIK) in that it's a flapless procedure involving the removal of corneal epithelium with different techniques including manual removal , alcohol assisted removal or excimer laser assisted removal with phototherapeutic keratectomy (PTK). Mechanical or alcohol assisted debridement of the epithelium may lead to potential basement membrane (BM) injury ,with resultant more significant haze and pain compared to laser assisted epithelial removal known as 2 step trans-epithelial PRK (PTK-PRK).

Single step trans-epithelial PRK allows removing the epithelium and stroma in a single step with a single ablation profile.

Previous studies paid particular attention for comparing the 2 step PTK-PRK procedure or the new single step PRK procedure to the conventional PRK procedures involving epithelial removal whether manual or alcohol assisted.

The aim of this study is to focus on comparing the different outcomes of the new single step Trans-epithelial PRK (StreamLight Technology) versus the routine 2 step PTK-PRK in terms of postoperative vision, epithelial healing, pain scoring and haze evaluation.

Study Design
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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 50 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Outcomes of a New Trans-epithelial Photorefractive Keratectomy (Streamlight PRK) Compared to Conventional PRK Procedures
Actual Study Start Date : June 1, 2020
Actual Primary Completion Date : June 30, 2021
Actual Study Completion Date : June 30, 2021

Resource links provided by the National Library of Medicine


Arms and Interventions
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Arm Intervention/treatment
Active Comparator: Patients planned to undergo conventional 2 step trans-epithelial PTK-PRK

Patients planned to undergo:

  1. Epithelial removal using Phototherapeutic Keratectomy PTK as a separate step.
  2. Laser Vision Correction using Excimer laser wavefront optimized technology.
 Procedure: Photorefractive keratectomy (PRK)
Photorefractive keratectomy (PRK) is a surgical procedure used by ophthalmic surgeons to treat patients presented with refractive errors and involves corneal epithelial removal followed by application of excimer laser to correct different refractive errors including Myopia, Hyperopia and Astigmatism.
Active Comparator: Patients planned to undergo the new single step trans-epithelial (StreamLight) PRK.

Patients planned to undergo:

Epithelial removal and Excimer wavefront optimized Laser Vision Correction in a single step using the new StreamLight Technology.

 Procedure: Photorefractive keratectomy (PRK)
Photorefractive keratectomy (PRK) is a surgical procedure used by ophthalmic surgeons to treat patients presented with refractive errors and involves corneal epithelial removal followed by application of excimer laser to correct different refractive errors including Myopia, Hyperopia and Astigmatism.


Outcome Measures
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Primary Outcome Measures :
  1. Uncorrected distant visual acuity (UDVA) [ Time Frame: 6 months ]
    Visual acuity measurement using Snellen's Acuity Chart and will be expressed as decimal notation

  2. Postoperative Refraction (Spherical equivalent) [ Time Frame: 6 months ]
    Measured by Topcon Auto-Keratorefractometer


Secondary Outcome Measures :
  1. Epithelial healing duration [ Time Frame: 2 weeks ]
    Time for the epithelium to heal reported in days after PRK procudre

  2. Postoperative pain [ Time Frame: 1 week ]
    Verbal Rating Scale(a series of words commonly used to describe pain (0: no pain, 1: mild pain, 2: moderate pain, 3: severe pain, 4: disabling pain)

  3. Postoperative Haze [ Time Frame: 3 months ]

    Corneal Haze scoring using slit lamp bio-microscopy according to Fantes scoring system:

    0: No haze, completely clear cornea

    0.5: Trace haze seen with careful oblique illumination

    1. Haze not interfering with visibility of fine iris details
    2. Mild obscuration of iris details
    3. Moderate obscuration of the iris and lens
    4. Complete opacification of the stroma in the area of the scar, anterior chamber is totally obscured


Eligibility Criteria
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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

  • Inclusion Criteria: Candidates for Laser vision correction (LVC) with

    1. Myopia up to -6 diopters
    2. Myopic astigmatism up to -4 diopters
    3. Corneal thinnest location ≥ 500 um and a residual stromal bed ≥ 300um.

  • Exclusion criteria

    1. Patients not candidates for LVC.
    2. Hyperopic patients.
    3. Systemic disease that contraindicates LVC.
    4. Intra- or post-operative complications.
Contacts and Locations
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Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04710082


Locations
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Egypt
TIBA eye center
Assiut, Egypt
Sponsors and Collaborators
Assiut University
More Information
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Publications:

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Responsible Party: Mahmoud Abdel-Radi, Principal Investigator, Assiut University
ClinicalTrials.gov Identifier: NCT04710082    
Other Study ID Numbers: TEPRK
First Posted: January 14, 2021    Key Record Dates
Last Update Posted: July 20, 2021
Last Verified: July 2021
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Mahmoud Abdel-Radi, Assiut University:
Photorefractive Keratectomy PRK
Phototherapeutic Keratectomy PTK
Trans-epithelial PRK
Laser Vision Correction LVC
Additional relevant MeSH terms:
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Astigmatism
Refractive Errors
Eye Diseases