Dioptrimeter

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Dioptrimeter

 

an instrument for measuring the refractive power of an optical glass (glass in spectacles) expressed in diopters (D) and for determining the positions of the principal meridians of an astigmatic lens in spectacles. It consists of a collimator, an optical tube, a reading microscope, a mechanism for holding the lens being measured, and a mechanism for measuring the diameter of, centering, and marking the lens. The dioptrimeter makes it possible to determine the power of an optical glass with an accuracy of ±0.12 D.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.