Zeiss CIRRUS HD-OCT 500, User Manual

Page: 161 / 352

CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12
Posterior Segment
8-39
GCL+IPL Summary Graphs
As described in "
Guided Progression Analysis" on page 8-31
GCL+IPL Average
Thickness Graphs identify global thinning in the retinal nerve fiber layer by calculating a
trend over time.
cáÖìêÉ=UJOQ=^îÉê~ÖÉ=d`iHfmi=qÜáÅâåÉëë=~åÇ=qçí~ä=pìéÉêáçêLfåÑÉêáçê=qÜáÅâåÉëë=dê~éÜë=çîÉê=íáãÉ
For Ganglion Cell GPA three graphs can be seen as shown in Figure 8-24 :
1. The graph of the overall average thickness of the GCL + IPL is calculated by dividing
the selected GCA annulus into 6 sectors and taking the average. For example, in
Figure 8-15 , the average of all 6 OS sectors is 79.5.
2. The graph of the Total Superior Thickness is determined by averaging the top 3 sectors
(in Figure 8-15 , 91.6)
3. The graph of the Total Inferior Thickness is determined by averaging the bottom 3
sectors (in Figure 8-15 , 67.3).
NOTE: Do not use GCL Guided Progression Analysis with thickness maps or cubes with
clear segmentation errors, or where the fovea is far from the center of the scan. If the
annulus is simply off-center, return to the Ganglion Cell OU Analysis ("
Macular
Thickness OU Analysis" on page 8-16 ) to make adjustments.
NOTE: The GCL Guided Progression Analysis automatically excludes data where the Scan
Strength is less than 6. However, such data can be included by using the Manual Selection
function.
GCL+IPL Summary Chart
Ganglion Cell GPA has two different indicators for detecting Ganglion Cell change, each
with a checkbox in the summary:
• GCL +IPL Thickness Map Progression (best for focal change)
• GCL +IPL Thickness Progression (best for diffuse change)