Definition of diopter in English:
A unit of refractive power that is equal to the reciprocal of the focal length (in meters) of a given lens.
- The focusing power of a lens is measured in dioptres.
- Refractive error is measured in dioptres, and myopia is designated with a minus sign.
- The difference between the focusing powers of these two axes, measured in dioptres, is the astigmatism.
Definition of diopter in:
- British & World English dictionary