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Eyesight project Describe causes and symptoms of long and short sight and how they are corrected Introduction These extremely common problems are the result of small variations in the shape of the eyeball that affect the ability of the lens to focus light on the back of the eye. This focuses by varying the thickness of the lens, using tiny muscles around its perimeter. If the eyeball is either too short or too long in relation to the maximum power of the lens then the light can never be focused and vision is blurred. Short sight, myopia, results from having an eyeball too long for the focusing power of the lens. This means that light gets focused in front of the retina unless the object is brought extremely close to the eye. The opposite situation is the case in long sight, where the eyeball is short in relation to the power of the...

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