Orthokeratology for High Myopia (OHM) Study

February 14, 2021 updated by: Pauline Cho, The Hong Kong Polytechnic University
This project aims to investigate/examine high myopic subjects on full correction ortho-k (using Topaz ortho-k lenses for high myopia) compared to subjects undergoing partial reduction ortho-k and their relationship with myopia and myopic progression.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

For many years, commercially-available ortho-k lenses aim to reduce low - moderate myopia. Attempts to use these lenses for reduction of high myopia have been shown to give rise to complications such as corneal staining and lens decentration. Thus, practitioners may choose a more conservative way for high myopic children, that is, offering partial reduction ortho-k. Partial reduction ortho-k is target for 4.00-5.00D reduction and the residual refractive errors will be corrected with single vision spectacles to allow good visual acuity in the daytime. Partial reduction ortho-k has been shown to slow axial elongation in high myopic children, however, the main disadvantage is that the children have to wear spectacles in the daytime to correct residual refraction.

Euclid has recently designed a new lens, Euclid's Topaz, for high myopic children. It is currently commercially available to correct myopia for up to 10 D. However, evidence of its effectiveness for visual correction and slowing AL growth is lacking. While numerous studies have shown that orthokeratology is an effective clinical treatment to slow axial eye growth in children, the exact mechanism underlying this reduction in myopia progression associated with orthokeratology remains unclear.

Study Type

Interventional

Enrollment (Anticipated)

66

Phase

  • Not Applicable

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

Study Contact Backup

Study Locations

  • Hong Kong
      • Kowloon, Hong Kong
        • Recruiting
        • School of Optometry, The Hong Kong Polytechnic University
        • Contact:
        • Contact:
        • Principal Investigator:
          • Pauline Cho, PhD

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

5 years to 11 years (Child)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Myopia: at least 5.00D in one eye or in both eyes
  • Astigmatism: ≤1.50D; with-the-rule astigmatism (axes 180 ± 30) ≤1.25D; astigmatism of other axes ≤0.50D in both eyes
  • Anisometropia: not be more than 1.00D in the former and not more than 2.00D in the latter.
  • Best-corrected Monocular Snellen visual acuity 6/7.5 or better

Exclusion Criteria:

  • Strabismus at distance or near
  • Previous experience in contact lens wear or myopia control treatment (e.g. refractive therapy or progressive spectacles)
  • Contraindication for contact lens wear and orthokeratology (e.g. limbus to limbus corneal cylinder and dislocated corneal apex)
  • Previous history of ocular surgery, trauma, or chronic ocular disease
  • Concurrent use of medications that may affect tear quality or contact lens wear
  • Systemic or ocular conditions that may affect tear quality or contact lens wear (e.g allergy and concurrent medication) or that may affect refractive development (e.g Down syndrome, ptosis)
  • Poor compliance to tests (e.g poor fixation in noncontact tonometry or intolerance of lens wear)
  • Not willing to comply with the allocated treatment, use and care of lenses and follow-up schedule

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

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: ortho-k lenses and thinner spectacles
participants using conventionally designed ortho-k lenses (target for 4.00D) and thinner spectacles during day time
Device: ortho-k lenses and thinner spectacles
Conventinally designed (Emerald) ortho-k lenses (target for -4.00D) and thinner specs during day time
Experimental: newly designed ortho-k lenses
participants using newly designed ortho-k lenses for high myopia (target for full correction)
Device: newly designed ortho-k lenses
Newly designed (Topaz) ortho-k lenses for high myopia (target for full correction)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in axial length elongation over 24 months.
Time Frame: 2 years
To determine the change in axial length measured at baseline and two years after lens wear using IOLMaster
2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
First fit success rate of a newly designed ortho-k lens for high myopic children
Time Frame: 1 month
The success rate in using the first pair of lenses to achieve target refractive correction will be determined
1 month
Quality of life (questionnaire)
Time Frame: 3 months
Quality of life will be determined by questionnaires (using revised Pediatric Refractive Error Profile (PREP) 1 in traditional Chinese version) before and after ortho-k in the two groups of subjects
3 months
Ocular aberration
Time Frame: 2 years
Ocular aberration will be measured by Complete Ophthalmic Analysis System (COAS) aberrometer
2 years

Collaborators and Investigators

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

Sponsor

The Hong Kong Polytechnic University

Collaborators

Aston University
Queensland University of Technology

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 (Actual)

August 4, 2018

Primary Completion (Anticipated)

November 1, 2023

Study Completion (Anticipated)

January 1, 2024

Study Registration Dates

First Submitted

February 21, 2019

First Submitted That Met QC Criteria

March 18, 2019

First Posted (Actual)

March 19, 2019

Study Record Updates

Last Update Posted (Actual)

February 16, 2021

Last Update Submitted That Met QC Criteria

February 14, 2021

Last Verified

February 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HSEARS20180322002

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

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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