A person can see the objects lying between 25 cm and 10 m from his eye. His vision can be corrected by using lens of power:
- 0.1 D
His distance of distinct vision at 25 cm is normal. By using a concave lens of focal length 10 m he will be able to see distant objects.
P =1 /f
=1/ -10 m
=-0.1 D