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TEST PARAMETERS AND STRATEGIES
REV.B 02/03 PN 51680-1
HUMPHREY FIELD ANALYZER
II -
i
series
One of the most important test parameter settings is strategy. For both screening and threshold
testing, the strategy can affect the total test time and the precision to which the measurements
are made. The strategy also dictates whether screening test results are displayed as qualitative
(symbols) or quantitative (decibels) information. All threshold strategies yield quantitative
results. Each measures the threshold at every test point. They differ only in the method used.
Refer to Tables 4.1 and 4.2 for a more detailed explanation of screening and threshold
parameters, respectively.
Table 4.1: Screening Test Parameters
(Standard parameter settings appear in
bold print
)
Screening
Parameter
Description
Parameters
Settings
Test Strategy
Two Zone
For each point in the test pattern, a stimulus is
presented 6 dB brighter than the expected hill of vi-
sion. Printouts display circles (O) for seen stimuli
and boxes (
■
) for missed stimuli. Since screening
is done with an intensity 6 dB brighter than the ex-
pected threshold, missed points are known to be at
least 6 dB deep.
Three Zone
Same as Two Zone, except each missed point is
measured again at maximum intensity of 10,000
apostilbs (0 decibels) to determine if the defect is
absolute. Printouts display circles (O) for seen
stimuli, “X’s” for relative defects, and boxes (
■
) for
absolute defects.
Quantify Defects
Same as Two Zone, except the sensitivity at each
missed point is measured relative to the expected
threshold. Printouts display circles (O) for seen
stimuli, and numbers (in decibels) to indicate the
depth of any defects. The greater the number, the
lower the retinal sensitivity (deeper the defect).
Test Speed
Normal
Two stimulus presentation speeds are available.
Slow
The test speed may be changed while a test is in
progress. The Normal setting automatically
adjusts test speed for a slow responding patient.
Fixation Target
Central
Yellow light in the center of the bowl.
Small Diamond
The Small Diamond is located below the Central tar-
get, and should be used when a patient cannot see
the central fixation light (e.g. macular degenera-
tion). The patient should look in the center of the
diamond formed by the four lights.
TEST STRATEGIES
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Summary of Contents for HUMPHREY 720i
Page 1: ...HUMPHREY FIELD ANALYZER II i series USER S GUIDE Model 720i Model 740i Model 745i Model 750i...
Page 4: ......
Page 26: ...1 18 INTRODUCTION INSTRUMENT SETUP REV B 02 03 PN 51680 1 HUMPHREY FIELD ANALYZER II i series...
Page 116: ...6 8 TEST RELIABILITY REV B 02 03 PN 51680 1 HUMPHREY FIELD ANALYZER II i series...
Page 208: ...10 20 CUSTOM TESTING REV B 02 03 PN 51680 1 HUMPHREY FIELD ANALYZER II i series...
Page 284: ...12 14 CARE AND CLEANING REV B 02 03 PN 51680 1 HUMPHREY FIELD ANALYZER II i series...
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