Zeiss HUMPHREY 720i, User Manual

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TEST PARAMETERS AND STRATEGIES 4-15
REV. B 02/03 PN 51680-1 HUMPHREY FIELD ANALYZER
II -
i series
5. Corrected Pattern Standard Deviation (CPSD) values are not available when
Short-term Fluctuation is turned OFF. Fluctuation may be turned ON at the
Parameter Setup screen without altering any other test parameters. The test will
run longer as the HFA II retests additional points when fluctuation is turned ON. If
you wish to run most Blue-Yellow tests with fluctuation ON, refer to Section 2:
“Altering the Main Menu Screen”.
6. Blue-Yellow perimetry tests take only about 15% longer than conventional perimetry.
The most likely explanation for this is simply that current testing algorithms are not fully
optimized for Blue-Yellow. In any case, 15% is only about 1 additional minute in a 6
minute test, and does not appear to be a serious drawback. SWAP and STATPAC for Blue-
Yellow both fully support the use of FastPac. Using FastPac will greatly improve patient
acceptance simply because it significantly shortens test time.
Specificity is the ability of a diagnostic technique to correctly identify actual normals as being
normal. Humphrey’s STATPAC for Blue-Yellow was designed to provide the same level of
specificity for SWAP as currently enjoyed in standard white-on-white Humphrey perimetry.
The original Blue-Yellow research protocols called for laborious determination of the yellow-
ness of the crystalline lens. One conclusion of these protocols was that such measurements
added little if anything to the diagnostic power of the procedure
8
. Measurement of the crystal-
line lens does add information about the overall height of the hill of vision, but most of the
visual field information used in glaucoma diagnosis has to do with localized sensitivity loss, not
with general sensitivity. From a practical point of view, crystalline lens measurements do not
appear to be worth the clinical time consumed.
Although Humphrey’s Blue-Yellow Perimetry is available for screening tests in addition to
threshold tests, research studies dealing with Blue-Yellow have involved threshold testing
exclusively. Because screening strategies have been optimized for white testing, you may find
an increased number of screening fields to appear abnormal. We suggest for now you use
Blue-Yellow testing only with the threshold testing strategies.
Specificity of blue-yellow
testing
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