Zeiss CIRRUS HD-OCT 500, User Manual

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CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12
Posterior Segment
8-37
Optic Nerve Head Changes
RNFL Guided Progression Analysis includes features to follow changes to the optic nerve
head. This includes the following:
• A graphical plot of the Average Cup–to–Disc Ratio as a function of patient age using
the same layout as the graphical plots of RNFL average thickness measurements
versus patient age. This graphical plot is available on a second page of the analysis
screen. You may access this page by selecting the ONH toggle button.
• The GPA summary box also includes a colored checkmark whenever “Possible Loss”,
“Likely Loss”, or “Possible Increase” has been detected using the Average Cup-to-Disc
Ratio. Note that ACDR increases as the thickness of RNFL decreases. Therefore,
”Possible Loss” of RNFL is indicated by an increase in ACDR, and thus ”Possible Loss”
is checked when an there is an increase in ACDR observed (that exceeds the expected
variability of ACDR).
• The RNFL thickness maps that are displayed as a function of time include a mask to
indicate the location of the cup and disc boundaries. This display is similar to what is
seen on the ONH & RNFL OU Analysis.