What is hypermetropia?

Explanation

Hypermetropia (Long-sightedness) : A person suffering from hypermetropia can see distant objects clearly but cannot see nearby objects so distinctly. For such a defective eye the image of the nearby object N is formed behind the retina and not on the retina itself, therefore, the image of the nearby objects appears blurred. The near point of the eye is at N (the least distance of distinct vision, 25 cm) but for defected eye, near point gets shifted at larger distance say at P, as shown in Fig.
Causes of Long-sightedness. This defect arises due to either of the following two reasons :
(i) The eyeball becomes too short (i.e., the distance of retina from the eye lens decreases).

(ii) Focal length of eye lens is too large.
Correction of hypermetropia : This defect can be corrected by using a convex lens of suitable focal length.
A convex lens forms the image of the nearby object N at the point P, near point of the defective eye and hence forms the image of object on the retina itself.