A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?

Q. A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?

 

Answer:-

The distance of far point x = 1.2m
To view distant objects, concave lens of focal length -1.2 should be used.
i.e. f = -x = -1.2m
Power of lens = 1/f = 1/(-1.2m) = -0.83D

To correct this defect of vision, he must use a concave lens. The concave lens will bring the image back to the retina