Range of diopter measurement

0 Diopter – ±20 Diopter

Minimal scale value 

0.125D at 0D to ±5D, .25 at ±5D to ±20D

Astigmatism axis of cylindrical lens

0 to 180°, minimum scale value 5°

Prism base angle

0 to 180°, minimal scale value 5°

Regulation of ocular visibility

±5 Diopter

Size of lens

30MM to 90MM