Zeiss Humphrey II-i series, User Manual

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Humphrey Field Analyzer II-
i
series User Manual 2660021145640 A
Reference to Older Test Strategies L-3
Global Indices SF & CPSD
SF stands for Short-term Fluctuation, which the Humphrey Field Analyzer measures during the test.
It is an index of the consistency of the patient’s responses during the test and is obtained by testing
twice at ten (10) pre-selected points. Categories for p values are the same as for MD.
CPSD stands for Corrected Pattern Standard Deviation. It is a measure of how much the total shape
of the patient’s hill of vision deviates from the shape of the hill of vision normal for the patient’s age
(PSD), corrected for intra-test variability (SF). The hill of vision may be irregular in shape because of
unreliable patient responses, because of actual field losses, or a combination of the two factors.
Categories for “p” values are the same as for MD.
In calculating CPSD, STATPAC attempts to remove the effects of patient variability and to present
only the irregularity caused by actual field loss. CPSD depends on both PSD and SF and is, therefore,
not available unless the fluctuation option remains on during testing. The SITA testing strategies do
not calculate SF, therefore only MD and PSD are available when using SITA Standard or SITA Fast.
Change Analysis Printouts Displaying Mixed Test Strategies
When SITA results are mixed with Full Threshold results, FastPac results, or both, no SF or CPSD
values will display for the SITA tests.
Note: For the Change Analysis printout, you can mix tests done using the FastPac strategy with
those using Full Threshold. Because some of the STATPAC limits are slightly different depending on
whether FastPac was used or not, the significance lines for plotting PSD, SF, and CPSD will not be
on the printout if you are analyzing a series of FastPac and non-FastPac tests. Significance lines,
however, will be displayed for Mean Deviation. When SITA tests are included, the normal box plot is
not displayed for comparison (see
Figure L.1 ).
The Change Analysis program will also perform a regression analysis of mean deviation over time
when a series of tests using mixed strategies are used. When strategies are mixed, a minimum of six
test results are required for regression analysis; when all tests have used the same test strategy, only
five results are required. When tests are mixed with SITA results, or SITA Standard or SITA Fast are
mixed with each other, no linear regression will be performed. Mixture of strategies is not
recommended, however, as the relationship of results across strategies is complex and difficult to
quantify.
Note: The normal box plot and the p values for the global indices are not displayed. In addition, no
linear regression information is presented when SITA tests are included.