Purpose:
To compare false negative rates for Full Threshold (FULL) and SITA Standard automated perimetry in a group of glaucoma patients.
Methods:
One eye of 18 glaucoma patients with varying amounts of field loss underwent visual field testing once a week for 5 weeks on the Humphrey Field Analyzer II using 24-2 FULL and 24-2 SITA testing procedures. The order of presentation of test procedures was counterbalanced across patients. False negative responses were evaluated by presenting a stimulus 9 dB greater than a previously determined threshold value at specific locations in the visual field, and evaluating whether the patient responded to this suprathreshold stimulus for FULL and SITA testing procedures. We compared the percentage of false negative responses for the FULL test and the SITA test before (Peridata output - SITA A) and after (printout of results - SITA B) post processing of the data.
Results:
As shown in the figure, the percentage of false negatives was almost twice as high for FULL testing compared to the two SITA analyses. The standard deviation of false negative percentages was half as large for SITA B (post processing) compared to FULL and SITA A (Peridata) procedures. Because the distributions were not normally distributed, a Kruskal-Wallis analysis of variance revealed a statistically significant difference (H=13.094, p<0.001) for false negative percentages among the three evaluations
Conclusions:
Full Threshold test procedures yield about twice as many false negatives as SITA procedures. This may be related to the SITA method of testing for false negatives in relatively normal areas as opposed to any location (even if it has low sensitivity) with Full Threshold.