A 2-year Longitudinal Study on the Structural and Optical Effects of Orthokeratology Treatment on Eye

Study Overview
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Brief Summary
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This is a two-year longitudinal study investigating the optical and structural effects of increased compression factor of orthokeratology lens on eyes and the corresponding effect on change in choroidal thickness and therefore myopic control.

Official Title
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A 2-year Longitudinal Study on the Structural and Optical Effects of Orthokeratology Treatment on Eye

Conditions
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Myopic Progression

Intervention / Treatment
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* Device: Orthokeratology


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 6 to 10 years old Myopia: between 0.50 D and 4.00 D in both eyes Astigmatism: <1.50 D; ≤ 1.25 D for with-the-rule astigmatism (axes 180 ± 30); ≤ 0.50 D for astigmatism of other axes in both eyes Anisometropia: ≤ 1.50 D Symmetrical corneal topography with corneal toricity <2.00 D in both eyes Agree for randomization Exclusion Criteria: Contraindications for orthokeratology wear (e.g. limbus-to-limbus corneal cylinder and dislocated corneal apex) Any type of strabismus or amblyopia Myopic treatment (e.g. refractive surgery and progressive lens wear for myopic control) before and during the study period Rigid contact lenses (including orthokeratology lenses) experience Systemic condition which might affect refractive development (for example, Down syndrome, Marfan's syndrome) Ocular conditions which might affect the refractive error (for example, cataract, ptosis) Poor compliance for lens wear or follow-up

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 10 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 |
| --- | --- |
| No Intervention: Single-vision glasses<br>Subjects wearing single-vision glasses CR-39 of refractive index 1.56. | |
| Sham Comparator: Orthokeratology with normal compression factor<br>Subjects wearing orthokeratology lenses of normal compression factor about 0.50-0.75D. | Device: Orthokeratology<br> <br> * Other names: ortho-k;|
| Active Comparator: Orthokeratology with increased compression factor<br>Subjects wearing orthokeratology lenses of increased compression factor about 1.50-1.75D. | Device: Orthokeratology<br> <br> * Other names: ortho-k;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Axial length | axial progression of the eyeball | every 6 monthly in 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ocular aberration measured by Complete Ophthalmic Analysis System (COAS) aberrometer | ocular aberration measured by Complete Ophthalmic Analysis System (COAS) aberrometer | every 6 monthly in 2 years | 
| Corneal biomechanics (corneal response using ocular response) | corneal response using ocular response | every 6 monthly in 2 years | 
| Accommodation lag measured by Complete Ophthalmic Analysis System (COAS) aberrometer | accommodation lag measured by Complete Ophthalmic Analysis System (COAS) aberrometer using different accommodation targets | every 6 monthly in 2 years | 
| Choroidal thickness captured by Optical Coherent Tomographer (OCT) | choroidal thickness captured by Optical Coherent Tomographer (OCT) and measured using a customized software | every 6 monthly in 2 years | 

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