23. Optical center
Fig. 6
fig.6
Fig. 7
: Distance between rim center and optical center by the steps of 0.1mm
: Crossing distance from optical center to lens vertically
: Crossing distance from optical center to the bottom of lens vertically
24. FPD (Frame pupil distance) - Pupil distance of glasses frame
DBL (Distance between nasal points) - Distance between nasal points and frame.
(Fig.6,7)
DB
L
LL
L
PD
FPD
