What type of lens is used to correct (a) hypermetropia (b) myopia?
What type of lens is used to correct (a) hypermetropia (b) myopia?
(a) Convex lens
A defect of vision in which a person can't see the nearby object clearly (appears blurred), though can see the distant objects clearly is called hypermetropia. In this defect, light focuses beyond the retina, instead of directly on the retina.
Hypermetropia is corrected by using convex lenses of suitable focal length (or power) so that it can produce an additional conversion in the light rays and the final image is formed on the retina.
(b) Concave lens
A defect of vision in which a person can't see the distant object clearly (appears blurred), though can see the nearby objects clearly is called myopia. In a myopic eye, the light is focussed in front of the retina, instead of directly on the retina.
Myopia is corrected by using concave lenses of suitable focal length (or power) so that it can produce an additional diversion in the light rays and the final image is formed on the retina.
(a) Convex lens
A defect of vision in which a person can't see the nearby object clearly (appears blurred), though can see the distant objects clearly is called hypermetropia. In this defect, light focuses beyond the retina, instead of directly on the retina.
Hypermetropia is corrected by using convex lenses of suitable focal length (or power) so that it can produce an additional conversion in the light rays and the final image is formed on the retina.
(b) Concave lens
A defect of vision in which a person can't see the distant object clearly (appears blurred), though can see the nearby objects clearly is called myopia. In a myopic eye, the light is focussed in front of the retina, instead of directly on the retina.
Myopia is corrected by using concave lenses of suitable focal length (or power) so that it can produce an additional diversion in the light rays and the final image is formed on the retina.
