13
7.
Turn diopter measuring hand-wheel to obtain clearest focus of 3 long green
lines of round dot drone and cross-line drone. At this time, spherical diopter
(SPH), astigmatism degree (CYL) and astigmatism axis (AXIS) of this lens
are shown on the liquid crystal display screen (Fig. 13).
Fig. 12
Fig. 13
Matters Needing Attention
If it is required to do light degree switching, press measurement switching key +/,
then the device sends out sound of “DuDu”, and switched value is shown whereat
(Fig. 14).
Fig. 14
4.2.3
Measurement of Bifocal Lens
Function of measuring bifocal lens is to check how much near vision is added
to distant vision.
1.
According to measuring procedures of spherical lens and cylindrical lens
in above stated Sections 5.2.1 and 5.2.2, measure distant vision of bifocal
lens (i.e. diopter of big lens).
