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The Clue
Eyeglass prescription measurement (7 letter answer)
The Answer
DIOPTER
Tags
Notes
The answer DIOPTER is so rare that it appears less than once every 2500 puzzles.
Related Clues
Unit of refractive power of a lens
Definition
DIOPTER as a noun:
1. (diopter, dioptre) = a unit of measurement of the refractive power of a lens which is equal to the reciprocal of the focal length measured in meters; used by oculists