Question

plz help me guys,
Explain near sightedness,its cause and correction,with the help of figure.

Answer 1

Near-sightedness, also known as short-sightedness and myopia, is an eye disorder where light focuses in front of, instead of on, the retina.

Myopia occurs when the eyeball is too long, relative to the focusing power of the cornea and lens of the eye. This causes light rays to focus at a point in front of the retina, rather than directly on its surface.

Myopia may be corrected with lenses. Concave lenses are used here. They spread the light out before it reaches the convex lens in the eye, therefore letting the image focus directly on the retina.

Answer 2

Nearsightedness also can be caused by the cornea and/or lens being too curved for the length of the eyeball. In some cases, myopia is due to a combination of these factors. Myopia typically begins in childhood and you may have a higher risk if your parents are nearsighted.