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Refractive Error and Presbyopia
Very good information about refractive error and presbyopia. Refractive error exists when light does not focus perfectly onto the retina.
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Presbyopia
Information on how presbyopia affects the eye. Topics include symptoms, causes and treatments of the disease.
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All About vision.com: Eye Conditions and Diseases
Many articles with consumer information about lenses, eyewear, eye problems, and unique eye conditions. Vast content and many links to off-site information.