|MadSci Network: Physics|
The cornea refracts light because it is a lens, and that is what lenses do. By refracting the light, the
cornea focuses the light coming into the eye from all directions onto the retina, so that an image is
formed there. The retina then senses the image and converts it to electrical impulses that your
brain can interpret as an image.
Take a piece of white paper and hold it up. This is similar to your retina WITHOUT the cornea. Light hits the paper from all angles and no image is visible. Now take a lens (magnifying glass for example) and hold it in front of the paper. Change the distance between the lens and the paper until an image forms on the paper. The magnifying glass takes the place of the cornea. If the distance between them is not quite right, the image will be out of focus. That is what happens when someone has to wear glasses - because their cornea does not quite focus the light correctly on the retina.
Best regards, Todd
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