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Vision disorders

This interactive model illustrates the structure of an eye. A ray of light, having passed through the transparent cornea, enters the crystalline lens, where it refracts. Ciliar muscle provides the mechanism responsible for changing the curvature of the crystalline lens, thus altering its optical strength and making it possible to see objects that are located at variable distances from the eye. As it leaves the crystalline lens, the ray passes through a transparent glass-like body and is then focused on the surface of the retina. Sensory neurons that are located on the retina become excited and send neural impulses to the brain, which then reconstructs the image.

Set the switch buttons to "Short Sight" or "Long Sight". A shortsighted person sees some objects as blurry because the image forms by the crystalline lens short of the retina. Similarly, a far-sighted person sees unclear images because they are formed in his eye beyond the retina. It is possible to change the shortcomings of sight with the help of diverging or converging lenses (glasses.) In this model you can observe the impact of glasses if you press "Correction" button.

Press "Show Text" button to see text commentary.

© OpenTeach Software, 2007