Operation
Humphrey FDT User Manual
2660021149532 Rev. B 2015-11
3-10
Note: The Operator LCD Display will indicate if there is too much ambient light to
perform a reliable test. Lower the room lighting or change the test location until suitable
test conditions are achieved. Also, if the Patient Response Button is not connected or
the Patient Visor is in the wrong eye position, this will be indicated on the Operator LCD
Display.
The PERCENT COMPLETE scale, field location being tested, PATIENT RESPONSE, FIXATION
ERRORS, FALSE POS ERRORS and FALSE NEG ERRORS are displayed on the Operator LCD
Display during the test. Remind the patient to keep looking at the dot in the middle of the
screen and inform them of the approximate percent complete 3 or 4 times during the test
to encourage good patient compliance. Monitor the catch trials (FIXATION ERRS, FALSE
POS ERRS, and FALSE NEG ERRS) during the test. The catch trial display fields will be
highlighted on the Operator LCD Display if 2 or more catch trials have been responded to
by the patient. A high ratio on any of the catch trials indicates unreliable results and that
the test should be restarted or repeated.
For the right eye, near the end of a SCREENING N-30 TEST or a THRESHOLD N-30 TEST, the
FDT will pause for approximately 15 seconds. The internal fixation target will move to the
right on the screen. This allows two extra nasal points to be tested. At the same time the
following instructions will appear on the screen: “Inform Patient Fixation Moved Right.”
Advise the patient to re-fixate on the black spot in its new position and continue to press
the Button until the test completes. The instruction will note fixation moved to the left
when testing the left eye.
Patient reliability (Fixation, False Positive, and False Negative) errors that exceed 1 are
highlighted on the operator LCD and marked with an asterisk (*) on the results printout.
FULL THRESHOLD C-20 TEST (RIGHT EYE)
PERCENT COMPLETE:
2%
PATIENT RESPONSE : N
FIXATION ERRS : 0/0
FALSE POS ERRS : 0/0
FALSE NEG ERRS : 0/0
GRN BUTTON PAUSES
24 JUN 1997 04:05 PM
