Orthokeratology for High Myopia (OHM) Study

Sponsor

The Hong Kong Polytechnic University (Other)

Overall Status

Recruiting

CT.gov ID

NCT03881358

Collaborator

Queensland University of Technology (Other), Aston University (Other)

Enrollment

Location

Arms

64.9

Anticipated Duration (Months)

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Myopia High Myopia	Device: ortho-k lenses and thinner spectacles Device: newly designed ortho-k lenses	N/A

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 Design

Study Type:

Interventional

Anticipated Enrollment :

66 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Single (Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

Orthokeratology for High Myopia (OHM) Study

Actual Study Start Date :

Aug 4, 2018

Anticipated Primary Completion Date :

Nov 1, 2023

Anticipated Study Completion Date :

Jan 1, 2024

Arms and Interventions

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)

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)

Outcome Measures

Primary Outcome Measures

Change in axial length elongation over 24 months. [2 years]
To determine the change in axial length measured at baseline and two years after lens wear using IOLMaster

Secondary Outcome Measures

First fit success rate of a newly designed ortho-k lens for high myopic children [1 month]
The success rate in using the first pair of lenses to achieve target refractive correction will be determined
Quality of life (questionnaire) [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
Ocular aberration [2 years]
Ocular aberration will be measured by Complete Ophthalmic Analysis System (COAS) aberrometer

Eligibility Criteria

Criteria

Ages Eligible for Study:

7 Years to 13 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	School of Optometry, The Hong Kong Polytechnic University	Kowloon		Hong Kong

Sponsors and Collaborators

The Hong Kong Polytechnic University
Queensland University of Technology
Aston University

Investigators

Principal Investigator: Pauline Cho, PhD, The Hong Kong Polytechnic University

Study Documents (Full-Text)

None provided.

More Information

Publications

Responsible Party:

Pauline Cho, Professor, The Hong Kong Polytechnic University

ClinicalTrials.gov Identifier:

NCT03881358

Other Study ID Numbers:

HSEARS20180322002

First Posted:

Mar 19, 2019

Last Update Posted:

Feb 16, 2021

Last Verified:

Feb 1, 2021

Individual Participant Data (IPD) Sharing Statement:

Undecided

Plan to Share IPD:

Undecided

Studies a U.S. FDA-regulated Drug Product:

Studies a U.S. FDA-regulated Device Product:

Keywords provided by Pauline Cho, Professor, The Hong Kong Polytechnic University

Myopia control

Orthokeratology

Children

Additional relevant MeSH terms:

Myopia

Study Results

No Results Posted as of Feb 16, 2021