15
VIII. VERIFYING PACHETTE 2 CALIBRATION
Pachymeter calibration is verified by using the electronic calibration box (CalBox) that
is supplied with the
Pachette 2
(see Figure III-C). It is important to realize that the
CalBox does
not
calibrate the pachymeter. The CalBox generates a sequence of
precise, predetermined thicknesses that can be measured by the pachymeter. The values
of these thicknesses have been purposely selected to span the full measurement range of
the unit. Therefore, by measuring these predetermined thicknesses, the operator can
quickly verify that the pachymeter is properly calibrated.
Procedure For Verifying Calibration
1. With the
Pachette 2
turned off, connect the probe to the front panel.
2. Enter the CalBox mode by holding in the
↑
key and turning on the
Pachette 2
.
3. After power-up is completed, the display will indicate “CALBOX MODE” on the
top line and “#1 = 0u” on the bottom line.
4. Disconnect the probe and connect the CalBox to the
Pachette 2
.
5. Press the CalBox button until the LED lights, and the
Pachette 2
will begin taking
measurements.
If the LED fails to light or goes out before the test sequence has completed, or if
"POOR APPLANATION" is displayed, then replace the 9V alkaline battery.
If no measurements are taken within 2½ minutes after the CalBox button is pressed,
the CalBox will automatically turn off.
6. Observe actual measurement values of 200µm thru 1000µm in steps of 100µm.
(Units with FLAP option start at 100µm)
All values are based on a corneal velocity of 1640m/s and should be within ±5µm.
If any measurements are out of tolerance, contact DGH Technology, Inc.
7.
Important!
Before taking any corneal measurements, re-connect the probe and exit
the CalBox mode by pressing
CLEAR
.