Question

Match the disorders of the eye with the type of lens used for their correction.

• A. Cylindrical lens
• B. Concave lens
• C. Convex lens

Answer 1

People who suffer from myopia can see nearby objects clearly, but not the objects that are far. The image is formed in front of retina and not on it. In order to rectify the defect, glasses with concave lenses must be worn. Concave lenses diverge the light from distant objects in such a way that the refracted rays finally fall on the retina.

People who suffer from hypermetropia can see distant objects clearly, but not the objects that are near. In this, the image falls behind the retina. Correction of hypermetropia can be done by wearing glasses containing convex lenses. These lens converge the rays in such a way that the rays focus on the retina.

Astigmatism is because of non-uniform curvature of the cornea, resulting in a distorted or blurry vision at any distance. Correction of astigmatism can be done by using a cylindrical lens.