Potec PDR-7000 - Page 39

PDR-7000 Operation Manual
10.Refine the spherical power with the red-
green test.
1) Press
The SPH +0.50 D lens is automatically added to
fog the vision. The red-green chart is presented.
When the cylindrical power is 0.00, the
message whether the cross cylinder test is
skipped or not appears.
When the skip is selected, Steps 10 to 12 are skipped and the red-green test
starts in Step 13.
2) Reduce fogging gradually until the sharpness of the letters on the red and green
sides appears equal.
Letters on the red side are sharperTurn the dial clockwise by increments of one.
Letters on the green side are sharper Turn the dial counterclockwise by
increments of one
NOTE
In this spherical refinement, circle of least confusion is maintained on the retina for
the next cylindrical axis measurement with the cross cylinder. When the patient can
not see the red and green sides equally, make the green side sharper slightly.
11.Measure the cylindrical axis.
1) Press .
The dots chart is presented.
A cross cylinder lens is placed. The cross cylinder lens type is switched between [Auto],
[±0.25], and [±0.50].
When the cylindrical power is 0.00 in the cylindrical power measurement, Steps 11 and 12
are skipped.
2) Measure the cylindrical axis with the cross cylinder lens.
Flipped cross cylinder :
Ask the patient which is sharper, chart 1
presented by pressing or chart 2 presented
by pressing .
when chart 1 is sharper.
 Turn the dial counterclockwise by
increments of one.
(Also possible by pressing )
when chart 2 is sharper.
 Turn the dial clockwise by increments of one. (Also possible by pressing )
Repeat the above until the both charts appear equal.
Dual cross cylinder:
Charts 1 and 2 are presented simultaneously.
Both chart positions appear in the lower left corner of the screen.
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