How do you appreciate the different lenses for their role in our vision ?

Explanation

1) Now a days somany people are sufffering from either myopia or hypermetropia or presbyopia.
2) The defect, in which people cannot see ojbects beyond far point is called myopia.
3) Myopia can be rectified by using a concave lens.
4) The defect, in which people cannot see the objects between neart point and the least distance of distinct vision is called hypermetropia.
5) Hypermetropia can be rectified by using a convex lens.
6) Some people may suffer from both myopia and hypermetropia with ageing is called presbyopia.
7) Presbyopia can be rectified by using bi-focal lenses.
8) So, I appreciate the lenses , for their great role in our vision.