Question

Differentiate between short-sighted eye and long-sighted eye.

Answer 1

Short-sighted eye can see objects clearly and disctinctly, if they are placed near the eye.  Objects beyond a distance x, cannot be seen clearly.

Long-sghted eye can see objects beyond a distance clearly. It cannot clearly focus image of objects on retina if the objects are closer than that distance y.

Answer 2

Differences are:
i) Short-eye sightedness is called Myopia & Long-eye sigtedness is called Hypermetropia.

ii) In Myopia near objects can be seen properly; and distance objects cannot be seen properly whereas in Hypermetropia distance object can be seen clearly; and near objects cannot be seen clearly.

iii) In Myopia the eyeball elongates or the distance between the retina from the eye lens increases whereas in Hypermetropia the image of the object formed is behind the retina.

iv) Myopia is generally seen in young persons whereas Hypermetropia is observed in old people.

v) Myopia can be rectified by using spectacles with concave lens of appropriate focal length whereas in Hypermetropia it is rectified by using spectacles with convex lens of appropriate focal length.