Single-step Transepithelial PRK for Hyperopia

Twelve-Month Outcome of Single-step Transepithelial Photorefractive Keratectomy for Moderate Hyperopia and Hyperopic Astigmatism

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.

Study Overview

• Status: Completed
• Conditions: Moderate Hyperopia
• Intervention / Treatment: Procedure: Single-step transepithelial PRK

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 Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Assiut, Egypt, 71516
    • Tiba Eye Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: NONE

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Hyperopic patients planned to undergo 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.	Procedure: Single-step transepithelial PRK; Single-step transepithelial Photorefractive keratectomy (PRK) is a corneal refractive surgical procedure utilized to correct myopia, hyperopia and astigmatism where excimer laser is used in a single step to remove the corneal epithelium followed by stromal laser ablation to correct the patient's refractive error.

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Keratometry and corneal asphericity	Postoperative keratorefractive changes in mean keratometry (Km) and Q value were recorded using pentacam (Oculus GmbH, Germany)	12 months
Post-PRK haze	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.	12 months

Collaborators and Investigators

• Sponsor: Assiut University
• Investigators: Principal Investigator: Mahmoud Abdel-Radi, Assiut University

Publications and helpful links

General Publications

• Adib-Moghaddam S, Arba-Mosquera S, Walter-Fincke R, Soleyman-Jahi S, Adili-Aghdam F. Transepithelial Photorefractive Keratectomy for Hyperopia: A 12-Month Bicentral Study. J Refract Surg. 2016 Mar;32(3):172-80. doi: 10.3928/1081597X-20160121-01.

Study record dates

Study Major Dates

• Study Start (ACTUAL): December 1, 2019
• Primary Completion (ACTUAL): December 15, 2021
• Study Completion (ACTUAL): December 15, 2021

Study Registration Dates

• First Submitted: February 21, 2022
• First Submitted That Met QC Criteria: February 21, 2022
• First Posted (ACTUAL): March 2, 2022

Study Record Updates

• Last Update Posted (ACTUAL): July 12, 2022
• Last Update Submitted That Met QC Criteria: July 8, 2022
• Last Verified: July 1, 2022

More Information

Terms related to this study

• Keywords: Hyperopia; Photorefractive keratectomy; Single-step PRK; StreamLight PRK
• Additional Relevant MeSH Terms: Eye Diseases; Refractive Errors; Hyperopia
• Other Study ID Numbers: STEPRKH

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No