Effectiveness of Myopia Control by Breath-O Correct Orthokeratology Lenses

Study Overview
=================
Brief Summary
-----------------
This is a 24-month longitudinal randomized controlled trial aiming to evaluate the effectiveness of myopia control by Breath-O correct orthokeratology lenses in different myopia progression groups classified according to their initial electro-retinal responses.

Detailed Description
-----------------
Myopia is the most common refractive error in the world. In Hong Kong, the number of children in myopia is on the rise and approximately 80% of children are myopic by the end of childhood. Orthokeratology is one of the most successful myopia control methods adopting the strategy of peripheral defocus, in which the natural emmetropization process is harnessed by the myopic defocus induced by the orthokeratology lenses.Currently, Breath-O correct lenses are new designed ready-made orthokeratology lenses which are made of new material with higher elasticity as compared traditional lens material. A recent study has shown young children with an initial weakened central electrical signal from the inner retina had faster myopia progression as measured by multifocal electroretinogram(ERG). We will classify the slow and fast progression group based on the ERG results, so as to evaluate the clinical effectiveness of the newly designed lenses in controlling myopia in children with different rates of progression.

Official Title
-----------------
Effectiveness of Myopia Control by Breath-O Correct Orthokeratology Lenses in Different Myopia Progression Groups

Conditions
-----------------
Myopia, Orthokeratology

Intervention / Treatment
-----------------
* Device: Breath-O orthokeratology lenses


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Refractive error: Spherical: -1.00D to -4.00D; Cylindrical: half of Sph (against-the-rule Astig.: less than -0.75D) Best corrected Visual acuity: monocular ETDRS 0.1 or better Exclusion Criteria: Ocular abnormality Contra-indicated for overnight orthokeratology lens wear History of refractive surgery Systemic diseases History of orthokeratology lenses wearing or other myopia control methods

Ages Eligible for Study
-----------------
Minimum Age: 8 Years
Maximum Age: 12 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Randomized clinical trial
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: OrthoK (orthokeratology)<br>Group wearing Breath-O corrected orthokeratology lenses for 2 years | Device: Breath-O orthokeratology lenses<br>* Specially designed rigid gas permeable lenses which reshapes corneal profile for myopia control has higher elasticity compared to traditional lens material.<br>|
| No Intervention: SV Lenses (Single vision)<br>Group wearing spectacle with single vision lenses for 2 years | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subjective Refraction | Refractive Error ( in Diopter ) | up to 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Axial Length | Length of eye ball | up to 24 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Myopia, Myopia Control, Orthokeratology, Electroretinogram, Multifocal Electroretinogram