Explain Hypermetropia with its correction.

1.       It is the defect in which human eye can see distant objects clearly but is unable to see nearby objects clearly.

2.       The image of near object falls behind retina. Two possible reasons of Hypermetropia are :

a.       Weak action of ciliary muscles causes low converging power of eye lens.

b.       The distance between eye lens and retina decreases on account of either shortening of eyeball or flattening of lens. In this case focal length of the eye lens is too long.

3.       A convex lens of suitable focal length can correct this defect.

4.       The rays coming from nearby object are first converged by convex lens and then converged by eye lens to retina.