30
11.
Once contact is achieved, it may be necessary to adjust the angle of contact to align
the probe with the visual axis. To do this, ensure the center of the probe tip is in stationary
contact with the center of the cornea. Then, slightly tilt the back end of the probe. As the
angle of contact changes and the probe comes closer to aligning with the visual axis, the
beep rate will increase. A high tone beep indicates the probe is properly aligned.
NOTE:
An aid for aligning the probe to the visual axis is, after contacting the center of the
cornea, adjust the angle of the probe until the back side of the probe is pointing at the
fixation target.
12.
In
Auto Measurement Mode
, a measurement is automatically recorded when proper
contact and alignment with the visual axis is detected. Typically, measurements will be
obtained almost instantaneously. AXL, ACD and LT measurements are ranked and placed in
the measurement bank. If the unit is configured for the
“
Aphakic
”
lens type, only AXL
measurements will be given.
If a measurement is not obtained successfully upon contact and/or the beep rate is still very
low, remove the probe from the cornea and position the probe at a slightly different
location or angle. Repeat this probe removal and repositioning procedure until a rapid beep
rate is obtained or a measurement is taken.
NOTE:
Refer to the
Alignment Ranking System
section for information on how
measurements are evaluated during Auto Measurement Mode.
In
Manual Measurement Mode
, a measurement is only recorded in the measurement bank
if the user presses the
Enter
key (on the keyboard) or
Right Foot Pedal
(accessory).
Measurements manually placed in the measurement bank are given a
“
MAN
”
ranking.
NOTE:
It is possible to acquire a video in Manual Measurement Mode and then enter
measurements during replay of the video. Refer to the
Reviewing A
-
Scan Videos and
Measurements
section.
13.
Scanning is stopped as follows:
In
Auto Measurement Mode
, the scan will stop automatically as soon as eight (8)
measurements are obtained that meet the alignment ranking and standard deviation
requirements. Scans can also be aborted manually (as stated below).
In
Manual Measurement Mode
, scans must be stopped manually.
To Stop scanning
†:
-
Click the
[STOP SCAN]
button; or
-
Press the
Space Bar
(on the keyboard); or
-
Press the
Foot Pedal
(Single Pedal accessory); or
-
Press the
Left Foot Pedal
(Double Pedal accessory)
14.
If measurements of the other eye are needed, click the
[CHANGE EYE]
†
button and repeat
steps
1
—
13.
CORNEAL COMPRESSION SENSITIVITY
The Compression Sensitivity (Comp track bar) adjusts the sensitivity of the unit in detecting
corneal compression. Higher settings allow for less compression, making measurements more
accurate, but also more difficult to obtain.
If a low
-
tone beep / constant tone is heard during the procedure, corneal compression has been
detected and measurements are being locked out. To correct this, maintain the probe alignment
and slowly withdraw the probe from the cornea to relieve compression until measurements are
obtained.
†
This command may be executed through voice control. Refer to the
A
-
Scan Voice Controls
section.
