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

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

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.

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.

Bifocal Soft Contact Lenses, Hydrophilic Bifocal Contact Lenses, Simultaneous Vision Bifocal Contact Lenses

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

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Tarrant J, Severson H, Wildsoet CF. Accommodation in emmetropic and myopic young adults wearing bifocal soft contact lenses. Ophthalmic Physiol Opt. 2008 Jan;28(1):62-72. doi: 10.1111/j.1475-1313.2007.00529.x.

Aller TA. Design of a prospective clinical trial of the use of bifocal soft contact lenses to control myopia progression (CONTROL). Proceedings of the 10th International Myopia Conference 2004:29.

Aller TA, Wildsoet C. Results of a one-year prospective clinical trial (CONTROL) of the use of bifocal soft contact lenses to control myopia progression. Ophthalmic and Physiological Optics 26(S1), 8-9.