My spectacles have a power of 1.5. In what units is this power measured ?

Question

My spectacles have a power of 1.5. In what units is this power measured ?

Answer 1

The unit of measure is called dioptre.

A dioptre, or diopter, is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres).

For example, a 3 dioptre lens brings parallel rays of light to focus at 1/3 metre.

Answer 2

Those be diopters, either plus or minus



Look 'em up on wikipedia, to learn more

Answer 3

it is measured in dioptres