In this image every visual field is represented as a box with 2 whiskers. This element is a compressed form of the Bebié curve (cumulative curve). The upper whisker reaches up to the best value, the lower whisker down to the worst value. The upper border of the box is an average good value (percentile 15), the lower border of the box an average bad value (percentile 85). The waist line is the median (percentile 50).
The box plot image shows the visual field development. Time is the X axis and total deviation (defect depth) the Y axis (height). The time axis is proportional, the distance between the boxes represents the time interval
The cross is the index MD. The MD values are connected to a line.
The box turns yellow, if an examination could be unreliable, i.e. the limits for quality indicators (false positive..) are exceeded. It also turns yellow, if a learning effect is suspected (see example).
Defect depth or total deviation are norm-related values. A normal value has 0 dB -- Click here for more information about this value type, the meaning and interpretation
If one region deteriorates and another improves, the box plot does not change.
MD and median are only equal if the value distribution is symmetrical.