Efficacy and Visual Quality of Orthokeratology Lenses With Different Designs

Orthokeratology (ortho-k) lens is very effective in slowing down axial elongation in myopic children by 30% to 63% when compared to children wearing single-vision spectacles or contact lenses. More recently, it is reported that the children wearing orthok lens of smaller back optical zone diameter (BOZD) demonstrated a smaller axial elongation when compared to children wearing lens with larger BOZD. We aimed to explored the myopia efficacy and visual quality of ortho-k with different BOZD (5.0mm or 6.2mm).

Study Overview

• Status: Completed
• Conditions: Myopia; Myopia; Refractive Error
• Intervention / Treatment: Device: Orthokeratology with 5.0mm back optical zone diameter; Device: Orthokeratology with a 6.2 mm back optical zone diameter

Detailed Description

This prospective study aimed to evaluate the efficacy of orthokeratology lenses with different back optical zone diameters (BOZD) in slowing axial elongation. Additionally, visual quality will be assessed through measurements of wavefront aberrations, contrast sensitivity, and subjective visual quality using a validated questionnaire. The study seeks to explore the effectiveness of various Ortho-K lens designs and the potential factors influencing their outcomes.

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Tianjin
    • Tianjin, Tianjin, China, 300020
      • Tianjin Eye Hospital Opotometric Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age between 8 and 13 years.
• Subjective refraction under cycloplegia: spherical power between -4.00 D and
• 1.00 D, with cylindrical power≤ 1.50 D.
• Best-corrected visual acuity (BCVA) of ≥ 1.0 based on subjective refraction.
• Willing to participate in the clinical trial and provide signed informed consent.

Exclusion Criteria:

• One eye met the inclusion criteria
• Patients with systemic diseases causing immunocompromised or affecting orthokeratology
• There are other eye diseases that affect orthokeratology lens wearing, such as dacryocystitis, blepharitis, various inflammation, glaucoma, etc
• Abnormal cornea
• Previous corneal surgery or corneal trauma history
• Active keratitis (e.g., corneal infection)
• Patients with best corrected distance visual acuity of less than 5.0
• Patients with corneal flat curvature lower than 39.00D, or higher than 48.00D
• Patients with refractive instability
• Patients with overt strabismus
• The corneal epithelium showed obvious fluorescent staining, which was not suitable for patients wearing orthokeratology lenses
• Patients with dry eye are not suitable for orthokeratology
• Patients with corneal endothelial cell density less than 2000 cells /mm2
• Patients who had worn rigid contact lenses (including orthokeratology lenses) within the previous 30 days

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental Group; Myopic children who need OK lens treatment	Device: Orthokeratology with 5.0mm back optical zone diameter; The orthokeratology lenses used in this study were Double Reservoir Lenses (DRL) manufactured by Precilens (Creteil, France). The lenses feature a dual reverse-curve design with a back optic zone diameter (BOZD) of 5.0 mm.
Active Comparator: Control group; Myopic children who need OK lens treatment	Device: Orthokeratology with a 6.2 mm back optical zone diameter; The orthokeratology lenses used were Euclid lenses manufactured by Euclid Systems (Herndon, VA, USA). These lenses feature a four-zone, five-curve design with a back optic zone diameter (BOZD) of 6.2 mm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in axial length	Axial length was measured with a biometer	The change of baseline and 1years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change of visual quality	The visual quality questionnaire used in this study was adapted from the questionnaire developed by Tilia et al. The questionnaire comprises five categories with a total of nine questions, each accompanied by descriptive text and illustrative images to assist participants in providing their responses. Participants were asked to select the image corresponding to each question, and their responses were converted into numerical scores ranging from 1 to 10, where a score of 1 represents the poorest visual quality.	Follow-up evaluations were conducted at baseline, and at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months after lens wear. The differences from baseline were calculated for each follow-up period.
Change of wavefront aberrations	Wavefront aberration data for the eye were obtained using a Hartmann-Shack wavefront sensor (i.Profiler plus, Carl Zeiss Co., Aalen, Germany). The data were analyzed using Zernike polynomial decomposition to calculate the root mean square (RMS) values of total higher-order aberrations (HOAs), spherical aberration, coma aberration, trefoil, astigmatism, and fourth-order aberrations.	Follow-up evaluations were conducted at baseline, and at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months after lens wear. The differences from baseline were calculated for each follow-up period.
Change of contract sensitivity	Contrast sensitivity was assessed using the OPTEC 6500P contrast sensitivity tester (OPTEC 6500P, Stereo Optical Company, Inc., Chicago, USA) at five spatial frequencies: 1.5, 3, 6, 12, and 18 cycles/degree. The contrast sensitivity scores were expressed in logarithmic units (base 10) following a logarithmic transformation.	Follow-up evaluations were conducted at baseline, and at 1 week, 1 month, 3 months, and 12 months after lens wear. The differences from baseline were calculated for each follow-up period.

Collaborators and Investigators

• Sponsor: Xiaoyan Yang
• Investigators: Principal Investigator: Tianjin Eye Hospital, Tianjin Eye Hospital Opotometic Center

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2021
• Primary Completion (Actual): March 31, 2022
• Study Completion (Actual): May 31, 2022

Study Registration Dates

• First Submitted: February 9, 2025
• First Submitted That Met QC Criteria: February 9, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 9, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Eye Diseases; Myopia; Refractive Errors
• Other Study ID Numbers: Different Orthk lens

Drug and device information, study documents

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