TO-3 is designed to measure the posterior vertex refraction (in the range from +25 to - 30 dptr) and the prismatic action of eyeglass lenses (in the range from 0 to 6 srad) with a diameter of 34 to 75 mm, and is also used when applying the position of the optical center or main sections in astigmatic lenses and the direction of the main sections in prismatic spectacle lenses.
The diopter meter is used in polyclinics in the selection of glasses and in the control of ready-made glasses in places where points are sold to the public. In addition, it can be used to measure individual lenses, mounted in the frame of the lenses, parts of glasses for glasses.

Measurement range of rear vertex refraction of spectacle lenses, diopter from +25 to –30

The price of the division of the scale of refractions, dptr 0,25

The accuracy of the device when measuring the posterior vertex refraction of spectacle lenses, in the ranges, diopters:

- from 0 to 6 dptr

- from 6 to 12 dptr

- from 12 to 15 dptr

-sv. 15 diopters ± 0,06

± 0.12

± 0.18

± 0.25

Range of measurement of prismatic action, srad from 0 to 6

Angular scale measurement range, degrees from 0 to 180

The accuracy of the device when measuring the prismatic action of eyeglass lenses in the ranges of:

-from 0 to 3 srad

- above 3

± 0.10

± 0.15

Diopter mass, not more than, kg 3.7

Measurement error on the angular scale, not more than, degree 1

Overall dimensions, not more than, mm 325 x 225 x 150