Percentile Plot

This image uses 11 percentiles (0% thru 100%) from every visual field. Percentiles are a compressed form of the Bebié curve (cumulative curve). Each percentile represents a rank in the total deviation values (defect depth): The percentile 0 is the best value, the percentile 50 the median and the percentile 100 the worst value.

The Percentile Plot shows the course of percentiles as a line diagram. Time is the X axis and total deviation (defect depth) the Y axis (height).

The line color indicates whether the percentile values have significantly deteriorated (red) or improved (green). Statistical method is the t-test

CONCLUSION: This image type shows the better, the medioce and poorer portions of the visual field in the time course. Learning effects and long-term fluctuations are well recognizable. -- The image contains no spatial information. For a complete evaluation, topographical trend analysis (SuperTrend, GATT) are needed in addition.

Further information

Example 1 (see above) shows improvement in the better portions (could be a learning effect) and, simultaneously, a deterioration in the poorer portions, i.e. the existing defects. This is a "balanced" trend which does not show in the index MD.
Example 2 shows a deterioration in all portions, but there is more loss in the worser portions. This example also shows the bottom effect (maximum defect depth, given by the measurement range).