what is myopia. . which causes and with diagrams
Answers
Answer:
Myopia is a defect of vision in which a person clearly sees all the nearby objects, but is unable to see the distinct object comfortably and his eye is known as myopia eye. A myopic eye has its far pint near that infinity. It forms the image of an distinct object in front of the retina as shown in the figure A.
Myopia can be caused by
1. increase in curvature if the lens.
2. increase in the length if the eye ball.
Since concave lens has an ability to diverge incoming rays, it us used to correct this defect of vision. The image is allowed to form at thee retina by using a concave lens of suitable power as shown in the figure B
solution
Explanation:
Myopia is defect of vision. It it it is also called as nearsightedness.
In this case the eye can see nearby objects clearly but the distant object appear indistinct.
This means that the far point of the eye is not at infinity but shifts closer to the eye.
In myopia the image of a distance object form in front of the retina.
There are two reason for this defect.
(1) The curvature of the Cornea and eye lens increase. The muscle near the lens cannot relax so that the converging power of lens remain large.
(2)The eyeball elongates so that the distance between the lens and retina increases.
The focal length of concave lens is negative ,so a lens with negative power is required for correcting myopia.
