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Orthokeratology for High Myopia (OHM) Study

Orthokeratology for High Myopia (OHM) Study

Status
UNKNOWN
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03881358
Enrollment
66
Registered
2019-03-19
Start date
2018-08-04
Completion date
2024-01-31
Last updated
2021-02-16

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

High Myopia, Myopia

Keywords

Myopia control, Orthokeratology, Children

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.

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.

Interventions

DEVICEortho-k lenses and thinner spectacles

Conventinally designed (Emerald) ortho-k lenses (target for -4.00D) and thinner specs during day time

DEVICEnewly designed ortho-k lenses

Newly designed (Topaz) ortho-k lenses for high myopia (target for full correction)

Sponsors

Queensland University of Technology
CollaboratorOTHER
Aston University
CollaboratorOTHER
The Hong Kong Polytechnic University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
7 Years to 13 Years
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

Design outcomes

Primary

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

Secondary

MeasureTime frameDescription
First fit success rate of a newly designed ortho-k lens for high myopic children1 monthThe success rate in using the first pair of lenses to achieve target refractive correction will be determined
Quality of life (questionnaire)3 monthsQuality 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 aberration2 yearsOcular aberration will be measured by Complete Ophthalmic Analysis System (COAS) aberrometer

Countries

Hong Kong

Contacts

Primary ContactPauline Cho, PhD
pauline.cho@polyu.edu.hk(+852) 2766 6100
Backup ContactYajing Yang, BSc
grace.yj.yang@connect.polyu.hk(+852) 6486 2435

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026