Question

What is hypermetropia? What are the possible reasons of hypermetropia? How is hypermetropia corrected? Explain with figures.

Answer 1

(a) Hypermetropia or Long Sightedness is an eye defect. A person suffering from it can see distant objects clearly but is not able to see nearby objects clearly.
(b) Hypermetropia is caused due to slight flattening of the eye ball and the image is formed behind the retina.
(c) The weak action of the ciliary muscles causeslow converging power of eye lens.
(d) The distance between eye lens and the retina decreases due to the flattening or shortening of the lens. This increases the focal length of the eye lens.
(e) This defect can be corrected by wearing spectacles having a convex lens which are of suitable focal length. The power of convex lens depends upon the degree of defect in the eye, it varies from person to person. The power of spectacles for a hypermetropic eye is positive because the focal length of the convex lens is positive.