Zeiss Humphrey II-i series, Руководство пользователя

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Humphrey Field Analyzer II-
i
series User Manual 2660021145640 A
Short-Wavelength Automated Perimetry (SWAP) 9-9
Note: It is particularly important to pay more attention to the STATPAC probability plots than to the
traditional grayscale plots. This is because reviewing the SWAP grayscale images using traditional
white-on-white rules may lead to a misinterpretation of the SITA-SWAP test results.
Note: SITA-SWAP test results and white-on-white test results cannot be printed on the same
Overview printout.
Blind Spot Monitoring with SITA-SWAP
The SITA-SWAP test uses the Size V spot size for both the stimulus and the blind-spot check. The Size
V stimulus is four times the angular size of the traditional Size III stimulus used with White-on-White
testing. It is common for patients to produce blind spot fixation errors with SITA-SWAP testing, even
when fixating well, due to the larger Size V stimulus. Therefore, fixation losses that exceed 20% are
not marked with the “XX” on the printout for SITA-SWAP tests, as is done for white-on-white tests.
In addition, the “Low Test Reliability” indication will not be displayed for high fixation losses on the
printout.
During the test, the HFA will still beep when the poor fixation level is surpassed, to alert you to
potential fixation problems. Attempting to re-find the blind spot during the test may help to lower
the number of fixation losses recorded and to silence the audible tone.
It is up to the clinician to determine whether the number of fixation losses is an indication of poor
patient fixation or an invalid blind spot indication. We recommend visually verifying whether the
patient’s fixation is stable during the SITA-SWAP test. Checking the Gaze Tracking graph will help to
verify patient fixation during and after the test.
Specificity of SITA-SWAP Testing
Specificity is the ability of a diagnostic technique to produce normal results in normal patients.
STATPAC for SITA-SWAP was designed to provide the same level of specificity for SITA-SWAP as is
currently enjoyed in standard white-on-white Humphrey perimetry.
The original SWAP research protocols called for laborious determination of the yellowness of the
crystalline lens. One conclusion of these protocols was that such measurements added little if
anything to the diagnostic power of the procedure. Measurement of the crystalline 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 justified.