Question

Short sightedness is otherwise known as
A) Myopia
B) Hyperopia
C) Astigmatism
D) Presbyopia

Answer 1

Hint:Eye is the organ of sight and the most important sense organ. These are situated in the deep protective bone cavities called orbits present in the skull.

Complete answer:
>Myopia: It is the condition in which the light focuses in front of the retina and not on the retina. So the person suffering from this has clear near vision but blurred distant vision due to longer antero-posterior diameter of the eyeball. It is also known as short-sightedness and it is corrected by using a concave lens.
>Hyperopia: It is also known as hypermetropia or long sightedness. The person with this defect has clear distant vision but blurred near vision. It occurs due to shorter antero-posterior diameter of the eyeball. The near objects are not focused on the retina but behind it. It can be corrected by using a convex or converging lens.
>Astigmatism: In this, due to irregular curvature of the corneal surface, some light rays bend more than the others which result in improper focusing and distorted images on the retina. The eyes are not completely round in this condition which causes blurry or distorted vision. A cylindrical lens is generally used for the correction of this defect.
>Presbyopia: It is a hyperopic condition caused due to the loss of elasticity of lens in old age. The ciliary muscles fail to increase its convexity. It is corrected by using convex or bifocal lenses.

Hence the correct answer is option ‘A’. Myopia.

Note:So myopia, hyperopia, astigmatism and presbyopia are defects of the eye that can be corrected using suitable lenses.There are few cases where a person may suffer from both myopia and hypermetropia. It can be corrected with the help of bifocal lenses.