You must have seen middle aged people holding a book away from their eyes to read properly. This is because they are not able to see the nearby objects clearly. We say that those people are suffering from hypermetropia (long sightedness).
Hypermetropia or hyperopia is the defect of the eye due to which the eye is not able to see clearly the nearby objects though it can see the distant objects clearly.
Let us now see how this defect is rectified. A long sighted eye forms image of a nearby object behind the retina. Thus, long sightedness is due to the decreased converging power of the lens. Therefore hypermetropia can be rectified by making the eye lens more convergent. This is done by placing a convex lens of suitable focal length before the eye lens as shown in the figure.
