Bifocal Soft Contact Lenses and Their Effect on Myopia Progression in Children and Adolescents.

Study Overview
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Brief Summary
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The purpose of this study is to determine whether bifocal soft contact lenses are effective in controlling the progression of myopia in children and adolescents that exhibit a tendency to excessively cross their eyes while reading (esophoria or eso fixation disparity). Several studies have demonstrated that bifocal or progressive multifocal spectacles are effective in slowing the progression of myopia in children either with near point esophoria and/or with inadequate focusing at near. A prominent theory for one cause of myopia progression is that poorly focused images on the back of the eye (retina) cause the eye to lengthen, causing an increase in myopia. Bifocal contact lenses may reduce this retinal defocus, reducing the stimulus to eye elongation, and thus may reduce myopia progression.

Detailed Description
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Myopia has become the focus of growing attention and concern because the prevalence of myopia appears to increasing in some populations (reaching 90% for some university student populations in Asia). There are serious risks to higher levels of myopia, including cataracts, glaucoma, retinal detachment and myopic retinal degeneration. Several studies have shown mild to moderate control of myopia progressionwith bifocal or multifocal spectacles in children with esophoria at near and/or with accommodative deficiencies. Pilot studies by the P.I. have suggested that bifocal contact lenses may control myopia progression in children with near point eso fixation disparity. CONTROL is a controlled, randomized, prospective, double-blind, one year study of the changes in myopia in 80-90 subjects from age 8-18 with low to moderate levels of myopia, low levels of astigmatism, and eso fixation disparity at near, when fitted with either bifocal soft contact lenses or single vision soft contact lenses. The primary outcome measures will be cycloplegic refraction and axial length measures.

Official Title
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Bifocal Soft Contact Lenses - Do They Slow Progression of Myopia Relative to Single Vision Soft Contact Lenses in Children and Adolescents?

Conditions
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Myopia, Esophoria, Fixation Disparity

Intervention / Treatment
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* Device: Bifocal Contact Lenses
* Device: Placebo Control


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Myopia between -0.50 and -6.00 Eso fixation disparity at 33cm with distance correction Astigmatism 1.00 or less Ability to wear soft contact lenses Exclusion Criteria: Presence of ocular disease preventing wear of contacts Pregnancy or nursing Use of certain medications

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 18 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bifocal Contact Lenses<br>Use of bifocal contact lenses to control the progression of myopia | Device: Bifocal Contact Lenses<br>* Use of bifocal contact lenses of varying add powers to control the progression of myopia<br>* Other names: Simultaneous Vision Bifocal Contact Lenses;|
| Placebo Comparator: Control<br>Single vision soft contact lenses | Device: Placebo Control<br>* Single vision soft contact lenses<br>* Other names: Single Vision Soft Contact Lenses;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Cycloplegic Autorefraction in One Year. |  | One year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Keratometric Changes at One Year. |  | One year | 
| Changes in Manifest Refraction at One Year. |  | One year | 
| Relationship Between Residual Fixation Disparity and Myopia Progression. |  | One year | 
| Changes in Cycloplegic Subjective Refraction in One Year |  | One year | 
| Changes in Axial Length at One Year. |  | One year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Myopia Progression, Myopia Control, Bifocal Contact Lenses, Esophoria, Fixation Disparity