UPSC 2016 CDS I GK Paper

If a myopic person has a power of –1.25 Dioptre, then the focal length will be 80 cm and the type of his lens will be concave. Power = 1/f. Therefore, f = 80 cm, and a person suffering from hypermetropia can see distinct objects clearly but faces difficulty in seeing the nearby objects clearly. It happens because the eye lens focusses the incoming divergent rays beyond the retina. This defect of vision is corrected by using a convex lens. A convex lens of suitable power converges the incoming light.