Describe the four vision problems of hyperopia, myopia, astigmatism, and presbyopia, including their causes and treatments

What will be an ideal response?

ANSWER: Answer will include that focusing is affected by the shape of the eye. If your eye is too short, nearby objects will be blurred but distant objects will be sharp. This is called hyperopia, or farsightedness. If your eyeball is too long, images fall short of the retina and you won't be able to focus distant objects. This results is myopia, or nearsightedness. When the cornea or the lens is misshapen, part of vision will be focused and part will be fuzzy. In this case, the eye has more than one focal point, a problem called astigmatism. All three visual defects can be corrected by placing glasses (or contact lenses) in front of the eye to change the path of light or through corrective surgery. As people age, the lens becomes less flexible and less able to accommodate. The result is presbyopia, from the Latin for "old vision," or farsightedness due to aging. Often older individuals can be seen reading a newspaper at arm's length because of presbyopia. If the middle­aged person was already wearing glasses for nearsightedness, they will need bifocal lenses to correct both near vision and distance vision.