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vision defects click to hear : vision defects

Images do not form on the retina, thus resulting in blurry vision; such defects are corrected by eyeglasses, contact lenses or even surgery.
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See vision defects in : french | spanish
astigmatism focus toric lens

astigmatism click to hear : astigmatism

Usually caused by a curvature of the cornea, it is manifested by blurred vision when viewing both near and far objects, depending on various axes.

focus click to hear : focus

Point where light rays converge to form an image; the brain interprets the retina’s upside-down image as right-side-up.

toric lens click to hear : toric lens

Has various powers depending on the rays’ axes of convergence; it is used to offset the visual distortion caused by the cornea.