Myopic Control for High Myopes Using Orthokeratology

Study Overview
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Brief Summary
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The purpose of this study is to evaluate and compare the eyeball elongation in high myopic children using partial correction orthokeratology and single-vision spectacles.

Detailed Description
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Orthokeratology (ortho-k) has been shown to have strong potential for retardation of myopic progression in low myopes. To date, clinical experience has shown the technique to be less effective in achieving full myopic reduction in high myopes. Would myopic control be possible for high myopes undergoing partial correction ortho-k treatment? A randomized, longitudinal study is designed to investigate the efficacy of partial correction ortho-k in retardation of myopic progression in high myopic children. Eye growth in terms of axial length elongation in children wearing ortho-k and over-spectacles (to correct residual refractive errors) (study group) and those wearing single-vision spectacles (control group) will be evaluated and compared.

Official Title
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High Myopia - Partial Reduction Orthokeratology Study

Conditions
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Myopia

Intervention / Treatment
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* Device: Orthokeratology lenses
* Device: Single-vision spectacle lenses


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Myopia (refractive sphere): > 5.75D Astigmatism: < ½ of myopia; with-the-rule astigmatism (axes 180 +/- 30) ≤1.25D; astigmatism of other axes ≤ 0.50D Spherical equivalent (SE): > 5.75D Anisometropia: ≤ 1.50D in both refractive sphere, refractive cylinder and SE Best corrected monocular visual acuity: equal to or better than 0.10 in logMAR scale in both eyes Willingness for randomization Availability for follow-up for at least 2 years Exclusion Criteria: Strabismus at distance or near Contraindication for contact lens wear and orthokeratology (e.g. limbus to limbus corneal cylinder and dislocated corneal apex Systemic or ocular conditions which may affect contact lens wear (e.g. allergy and medication) Systemic or ocular conditions which may affect refractive development (e.g. Down syndrome, ptosis)

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 11 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Orthokeratology lenses<br>Children wearing orthokeratology at night for partial correction and spectacles at daytime for residual refractive error will be study group | Device: Orthokeratology lenses<br>* Nightly use of orthokeratology to correct the refractive error and over-specs for a period of two years<br>* Other names: Corneal reshaping therapy;|
| Other: Single-vision spectacle lenses<br>Children wearing single-vision spectacles in the daytime for correcting the refractive error will serve as control group | Device: Single-vision spectacle lenses<br>* Daily use of spectacles to correct the refractive error for a period of two years<br>* Other names: Spectacles;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determine the change in cycloplegic axial length in the study and control groups |  | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determine the incidence of adverse effects in cornea, the palpebral, bulbar and tarsal conjunctiva in the study and the control groups |  | 2 years | 
| Rate of regression during the daytime |  | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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children, corneal reshaping, myopia control, orthokeratology, myopia