Zeiss CIRRUS HD-OCT 500, Руководство пользователя

Страница: 235 / 352

CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12
Analysis Related Report Options
10-13
measurements. A lavender “Possible Increase” summary box could indicate high
measurement variability.
Apply GPA Results in Context of the Patient
GPA reports statistically significant change for one eye, which may or may not be clinically
significant. Rate of loss, locations of the detected loss, age of the patient, stage of the
disease, and other clinical factors should be evaluated for clinical decisions. To confirm
that RNFL loss is clinically significant, correlate your results with other clinical tests such as
perimetry and IOP.
Consider Resetting the Baseline Scans
It is prudent to occasionally review the current Baseline scans and consider changing to a
more recent Baseline pair if there has been a significant change in the course of the
patient’s care. A stable period of RNFL thickness may follow a period of RNFL thinning due
to a change in therapy. This leveling off would be a good time to update the Baseline
images. This will allow GPA to flag change from this new point in time instead of having
the summary flags continuously checked off due to thinning that occurred at an earlier, less
stable time.
Statistical Significance
Guided Progression Analysis compares an observed change with its expected test–retest
variability, as illustrated in
Figure 10-11
.
cáÖìêÉ=NMJNN==aáëíêáÄìíáçå=çÑ=qÉëíÓoÉíÉëí=s~êá~Äáäáíó
Statistically Significant Change from Baseline
Guided Progression Analysis compares an observed change with its population test–retest
variability. The test–retest variability was determined by performing an in–house
repeatability and reproducibility study (results reported at ARVO 2008 in a poster, “
Inter–
Visit and Inter–Instrument Variability for CIRRUS HD-OCT Peripapillary Retinal Nerve Fiber
Cutoff Point for Flagging
Possible Increase (i.e.,

/2 = 97.5%)
Change considered within normal test–retest variability
(2.5% to 97.5%)
Cutoff Point for Flagging
Possible or Likely Loss
(i.e.,

/2 = 2.5%)
Measured RNFL Change