Prism Lenses; Prism Lenses Measured In X-Y; Prism Lenses Measured In B-P; Lens Offset - Reichert Lensometer LensChek Plus User Manual

Operation
(continued)
Marking Lenses

Prism Lenses

For prism lenses, the prescription is measured in
either X-Y, P-B, or in mm.

Prism Lenses Measured in X-Y

1. Select "X-Y" from "Prism" on the Setup screen.
2. Move the lens so that the prism values displayed
on the screen match with the ones on the pre-
scription. Refer to Figure OP-34.
The meanings of the prism values displayed are
as shown below.
Px I Base In
Px O Base Out
Py U Base Up
Py D Base Down
Prism Lenses Measured in P-B
1. Select "P-B" from "Prism" on the Setup screen.
2. Move the lens so that the prism values displayed
on the screen match with the ones on the pre-
scription. Refer to Figure OP-35.
P: Prism Value
B: Base Direction

Lens Offset

1. Select "on" from "Prism (mm)" on the Setup
screen to have the offset from optical center ap-
pear when measuring a lens.
2. Move the lens so that the offset value on the
screen reads 0.0 for both values.
Note: The arrows shown indicate the direction from
optical center. Refer to Figure OP-36.
Note: If "Prism" is set to "off", and "Prism (mm)" is
set to "on", the offset from optical center will
still be shown on the screen. "Prism" does
not have to be set to either "A-B" or "X-Y" in
order to have the offset shown.
30
(continued)
(base inward)
(base outward)
(base upward)
(base downward)
Figure OP-34 X and Y Values Match
Figure OP-35 P and B Values Match
Figure OP-36 Offset Value
15180-101 Rev. F