Monitoring And Maintaining The Patient's Eye Position; Video Eye Monitor; Gaze Tracking (Model 740I - 750I) - Zeiss HUMPHREY 720i User Manual

5-4
MONITORING AND
MAINTAINING THE
PATIENT'S EYE
POSITION

Video Eye Monitor

Gaze Tracking
(model 740i - 750i)
REV. B 02/03 PN 51680-1
All HFA II models feature a video eye monitor. This monitor, which is automatically visible on
the Start of Test screen, enables you to view the patient's test eye. Accurate placement of the eye
is important. When the cross-hatches are seen over the pupil, the eye is centered.
Use the video eye monitor to:
• position the test eye in the center of the trial lens holder
• monitor the patient during testing.
The three controls on the video eye monitor are: a plus sign (+) to brighten the image, a
minus sign (-) to dim the image, and an OFF button to turn off the monitor display. To re-
display the monitor, press the upper-left EYE button.
Figure 5.2: The Video Eye Monitor
Gaze Tracking is a unique fixation tracking system that records whether the patient is
properly fixating while stimuli are being presented. A brief initialization procedure is required
at the start of each test to calibrate and adjust the gaze tracker to the patient's eye. It is
imperative, therefore, that the patient maintain the same position during gaze initialization and
testing. Deviations are recorded and displayed on the test screen and on the printout.
Note: Some patients with small pupils, ptotic lids, interfering lashes, or strong
prescriptions may not be good candidates for gaze monitoring.
At the Start of Test screen, you can make changes to the fixation monitoring system or turn the
monitoring system off entirely by pressing CHANGE PARAMETERS and selecting the desired
option. Gaze monitoring may only be selected at the start of a test, although it may be turned
off at any time during the test.
HUMPHREY FIELD ANALYZER II -
TESTING
i
series