Question

How is +1.5 dioptre different from –1.5 dioptre? Define dioptre

Answer 1

Dioptre is the unit of power of lens

Power of lens are defined as the ability of eye lens  convergence or divergence .

It is also defined as reciprocal of focal length.

p=1/f (in m)

P=100/ f

P=+1.5 dioptre

1.5= 100/f

f= 100/1.5

=100x 10/15

=6.6 x10=+66cm

f=+66cm is suggested by doctor to treat Hypermetropia eye defect  and lens used is convex lens

P= -1.5 Dioptre is suggested by doctor to correct myopia eye defect by using concave lens