The far-sighted eye sees well without tension at a distance of at least 60 cm.What optical power of glasses

The far-sighted eye sees well without tension at a distance of at least 60 cm.What optical power of glasses should be taken so that the eye can freely distinguish objects at a distance of 20 cm

As you know from the physics course, the optical power of glasses in our case can be calculated using the following formula:

D = 1 / d0 – 1 / d1, where d0 is the distance at which the eye must distinguish objects, and d1 is, accordingly, the distance at which it actually distinguishes them.

Let us determine what optical power the glasses should have, which are intended for a person who sees at a distance of at least 60 cm:

1 / 0.2 – 1 / 0.6 = (3 – 1) / 0.6 = 3, (3)

We round up to the accepted diopters – 3.5.

Answer: 3.5.