elektron eye technology Henson 9000, Manual, Page: 51 / 155

51 Vis ua l field tes ts
E l e k t r o n E y e T e c h n o l o g y 2 0 1 8
3 .2 .7 P rogression : Rate of c h an ge
You can monitor the rate of change in the visual field in the Database program.
The progression screen below shows two graphs (one for each eye) that display the global
indices Mean Defect and Pattern Standard Deviation versus the age of the patient. As a visual
field defect gets worse the Mean Defect will become more negative and the Pattern Standard
Deviation more positive. Each data point represents a visual field record (collected or imported)
and when there are 4 or more data points a best fitting (least squares linear regression) line is
drawn through the points.
The Mean Defect rate of change (dB/year) is given below the plots along with its 95%
confidence limits. In the example shown the rate of change is -0.49dB/year in the RE while the
confidence limits are +/-0.36dB/year. As the rate is higher than the confidence limits the
progression is significant at the 95% limit.
The three vertical lines on each plot represent the time points that correspond to the three gray
scale images shown above each graph. When first entering the analysis these will be the last
three visits. You can move to different visits by clicking the left/right arrows to either side of the
gray scales.
Outliers in the data series can have a large effect upon the gradient of the regression lines. They
can be removed by clicking over the data point. Clicking a second time re-introduces the data
point.
The data can also be presented on a Glaucoma Staging System II (GSS) chart by clicking the
button.
The GSS II chart plots Mean Defect versus Pattern Standard Deviation and divides the plotted
area into seven stages (Normal, Borderline and five levels of loss).
Click to return to the database. On return visual field chart on the right hand side of the
screen will be replaced by an image of the last progression screen.
This can then be printed by pressing
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