Myopia is the defect in vision in which a person cannot see the distant objects clearly whereas in hypermetropia is the defect in which a person cannot see nearby objects clearly.
Hypermetropia is caused due to :
(i) Decrease in converging power of eyelens.
(ii) Too short eye ball.
In a hypermetropic eye, the image of near by object lying at normal near point N (at 25‌cm ) is formed behind the retina.
Hypermetropic eye can be corrected using convex lenses. When a convex lens of suitable power is placed in front of hypermetropic eye, then the diverging rays of light from the object are converged first by the convex lens used. This form a virtual image of the object at another near point N′.
Now, the rays can be easily focused by the eye lens to form an image on retina.