Total Deviation Probability Plots for Size V Perimetry: A Comparison With Size III

Abstract

 

Purpose:

 

To develop databases from a common set of normal participants for empiric probability plots for Humphrey size V and III testing and compare with the STATPAC^TM size III (SITA) database.

 

Methods:

 

We computed empiric probability plots from data collected from testing 60 normal participants (ages 40 - 78) on size III and size V testing. We then analyzed the probability plots of 120 Glaucoma patients (ages 38 - 81, mean deviation -6.67±4.4). We counted the number of test locations without and with loss at <1%, <2%, and <5% levels and compared the number of normal and abnormal test locations using size III vs. size V and size III results with Humphrey STATPAC^TM software results. Two-way repeated measures ANOVA was used to compare the number of normal and abnormal test locations among the three tests.

 

Results:

 

The graph shows the differences in the number of normal and abnormal test locations flagged by the three types of probability plots. There was no significant difference between size V and size III. At <2% and <5% loss, the number of abnormal test locations did not differ significantly among the tests. For the normal test locations, STATPAC^TM identified significantly more locations than size III; however, at <1% loss STATPAC^TM identified significantly fewer locations than size III.

 

Conclusions:

 

Size V full threshold testing gives a similar number of abnormal test locations in glaucoma patients. This may be due to its better retest variability and tighter confidence limits.  

 

Keywords: perimetry • visual fields