Single-step Transepithelial PRK for Hyperopia

Not Applicable

Completed

• Conditions: Moderate Hyperopia
• Interventions: Procedure: Single-step transepithelial PRK

• Registration Number: NCT05261685
• Lead Sponsor: Assiut University

Brief Summary

Hyperopia is one of the commonest refractive errors encountered in ophthalmology practice.

Laser in situ keratomileusis (LASIK) has been widely used to correct hyperopia especially with the advent of femtosecond laser technology allowing larger flap creation suitable for peripheral hyperopic ablations with resultant predictable, effective, and safe refractive outcomes. However, the encountered LASIK flap complications encouraged many surgeons to assess efficiency and safety of surface ablation techniques such as photorefractive keratectomy (PRK) to correct hyperopia.

Detailed Description

Although the initial refractive results of conventional manual or alcohol assisted PRK for hyperopia were encouraging, the frequently encountered post-PRK complications including undercorrection, overcorrection and regression of the hyperopic error had downgraded the conventional PRK as a preferred procedure for hyperopic correction.

Transepithelial PRK provides an alternative technique to uniformly remove the epithelium using the excimer laser to minimize the potential complications caused by mechanical or alcohol assisted epithelial removal in conventional PRK. Advances in transepithelial PRK technology have allowed refractive surgeons to remove the epithelium followed by stromal laser ablation in a single step instead of performing the procedure in 2 separate steps known as phototherapeutic keratectomy-photorefractive keratectomy (PTK-PRK).

Most of the previous studies paid particular attention to investigate the accuracy and safety of single-step transepithelial PRK in correcting myopia and myopic astigmatism. The aim of the current study is to evaluate the visual and refractive outcomes of the single-step transepithelial PRK procedure in correcting moderate hyperopia and hyperopic astigmatism.

Study Timeline

• Study Start: 2019-12-01
• Primary Completion: 2021-12-15
• Study Completion: 2021-12-15
• Study First Submitted: 2022-02-21
• Study First Submitted QC: 2022-02-21
• Study First Posted: 2022-03-02
• Status Verified: 2022-07
• Last Update Submitted: 2022-07-08
• Last Update Posted: 2022-07-12

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• Patients with moderate hyperopia with a hyperopic cycloplegic spherical equivalent between +2 and + 4.5 diopters D.
• A steep keratometry (Ks) ≤ 46 D.
• Minimum pachymetry of 500 μm with a calculated residual stromal bed exceeding 350 μm after epithelial and stromal ablation.

Exclusion Criteria

• Patients not candidate for corneal refractive surgery,
• Steep cornea (Ks > 46 D) with an expected postoperative keratometry > 48 D,
• Large angle kappa as estimated by Chord mu > 0.25 mm,
• Hyperopic amblyopia whether unilateral or bilateral with CDVA less than 0.2 . logMAR acuity,
• Recent contact lens wear, dry eye disease and autoimmune disorders.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Hyperopic patients planned to undergo single-step transepithelial PRK	Single-step transepithelial PRK	Patients with moderate hyperopia or hyperopic astigmatism were planned to undergo transepithelial PRK using the new single-step StreamLight PRK Technology.

Primary Outcome Measures

Name	Time	Method
Cycloplegic refraction	12 months	Cycloplegic sphere, cylinder and refractive spherical equivalent (SEQ) were measured with auto-keratorefractometer (KR-8900:Topcon, Korea republic)
Visual acuity	12 months	Uncorrected and corrected distance visual acuity (UDVA,CDVA) measurement using logMAR distant charts.

Secondary Outcome Measures

Name	Time	Method
Keratometry and corneal asphericity	12 months	Postoperative keratorefractive changes in mean keratometry (Km) and Q value were recorded using pentacam (Oculus GmbH, Germany)
Post-PRK haze	12 months	Post-PRK haze was evaluated using slit lamp based on Fantes et al. scale: Grade 0: No haze, completely clear cornea; Grade 0.5: Trace haze seen with careful oblique illumination; Grade 1: Haze not interfering with the visibility of fine details of the iris; Grade 2: Mild obstruction of iris details; Grade 3: Moderate obstruction of the iris and lens; Grade 4: Complete opacification of the stroma in the area of the scar, anterior chamber is totally obscured.

Trial Locations

Locations (1)

TIBA eye center; 🇪🇬 Assiut, Egypt