A Comparative Study Between Laser and Manual Removal of Corneal Epithelium for Photorefractive Keratectomy

December 19, 2024 updated by: Sandra Adel Nashed, Assiut University

Photorefractive keratectomy (PRK) is a laser eye surgery used to ablate the corneal stroma to correct visual refractive errors . PRK was developed in 1983 by Dr. Steven Trokel and colleagues and first performed in 1987 by Dr. Theo Seiler in Berlin. After receiving approval by the US Food and Drug Administration (FDA) in 1996, PRK was briefly the preferred surgical treatment of ametropia as it provided more predictable and stable results than incisional keratotomy. However, the number of PRK procedures fell in the late 1990s with the growing popularity of laser in situ keratomileusis (LASIK).

The study aims to compare the visual and refractive outcomes along with the pain score and patient satisfaction after photorefractive keratectomy in patients who underwent transepithelial or mechanical removal technique

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

Today, LASIK remains the most commonly performed visual refractive surgery; nonetheless, there remain select situations in which PRK may be preferable, such as post penetrating keratoplasty , in thin corneas , irregular topographies , treatment of some LASIK flap complications or residual refractive errors after LASIK, It is also indicated in patients that have a high risk for traumatic postoperative flap dislocation as athletes .Several modifications of the traditional PRK have been introduced in an attempt to overcome drawbacks of postoperative pain and corneal haze and irregular epithelial healing associated with the procedure .PRK employs an excimer laser ablation of the anterior corneal stroma beneath the epithelium .The first step of PRK is the removal of the superficial epithelial cells, which may be through a variety of techniques such as mechanical removal with spatula , application of a diluted alcohol solution , use a rotatory brush or transepithelial laser . Each of these techniques should be performed quickly to avoid desiccation and skillfully to avoid nicking Bowman's layer.

The first technique, Mechanical debridement, involves using a blunt spatula to scrape off epithelium from the periphery toward the center. The next step is wiping a sponge hydrated with balanced salt solution (BSS) or carboxymethylcellulose 0.5% across the cornea. This technique benefits from not depending on laser optics; however, mechanical debridement tends to be a lengthy process in inexperienced surgeons, which subsequently increases patient anxiety and reduces stromal hydration .

In the late 1990s, Transepithelial PRK was introduced as an alternative laser-assisted method for epithelial removal . The advantages of this method have been cited as minimum surgical time, zero contact of laser machine with corneal surface, shorter time for surface healing and visual correction, and decreased post-operative discomfort and dry eyes,this technique is popular among patients but requires a longer time for mastery.

Study Type

Observational

Enrollment (Estimated)

64

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Patients in the age group between 18 and 45 years will be included in this study. Subjects selected, which will consist of patients with myopia ( less than - 6 D ) will be divided into 2 groups.

Description

Inclusion Criteria:

  • • Age : older than 18 years old .

    • Gender: Include both males and females.
    • Stable refraction for at least 12 months .
    • Intraocular pressure less than 21mmHg.
    • A period without wearing contact lenses (more than 4 days for soft , more than 2 weeks for rigid contact lenses )
    • No history of any Autoimmune disease .
    • The refractive error must be one that can be treated by PRK

Exclusion Criteria:

  • _ patients with any eye disease (significant cataract or unstable glaucoma )

    • uncontrolled external disease such as blepharitis, dry eye syndrome, and atopy/allergy.
    • patients with Keratoconus and other abnormalities of the cornea such as corneal ectasias , thinning , edema , interstitial or neurotrophic keratitis and extensive vascularisation .
    • Patients with active systemic connective tissue disease such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA)
    • Ineligibility for Surgery: Exclude patients who are not suitable candidates for surgery .
    • Consider excluding pregnant or lactating women .
    • Patients unwilling to participate in the study .

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
group A
patients who are assigned for transepithelial PRK
group B
patients who are mechanical PRK using a spatula

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
visual acuity
Time Frame: 6 month
best corrected visual acuity (BCVA) will be observed for at least 6 months postoperatively.
6 month

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Assiut University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 1, 2025

Primary Completion (Estimated)

January 1, 2026

Study Completion (Estimated)

March 1, 2026

Study Registration Dates

First Submitted

December 19, 2024

First Submitted That Met QC Criteria

December 19, 2024

First Posted (Actual)

March 25, 2025

Study Record Updates

Last Update Posted (Actual)

March 25, 2025

Last Update Submitted That Met QC Criteria

December 19, 2024

Last Verified

December 1, 2024

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • Laser Vs Manual Keratectomy

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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