Comparison of visual field defects using matrix perimetry and standard achromatic perimetry.

PURPOSE: To compare visual field (VF) defects found by Swedish interactive thresholding Algorithm (SITA) perimetry and Matrix perimetry, a new VF device that utilizes frequency doubling technology in a 24-2 test pattern.
DESIGN: Prospective cross-sectional study. PARTICIPANTS: Fifty eyes from 50 subjects with SITA field defects were recruited for an observational study.
METHODS: Swedish Interactive Threshold Algorithm and Matrix VF testing were performed on patients from a glaucoma practice. To evaluate the learning effect on the performance of the VF, we tested subsets of each group who had previous experience with standard automated perimetry (SAP). MAIN OUTCOME MEASURES: Test duration, mean threshold, mean deviation (MD), pattern standard deviation (PSD), glaucoma hemifield test, and number of abnormal points on the pattern deviation plot were evaluated for each device.
RESULTS: Test duration was significantly shorter for Matrix (SITA, 357.0+/-85.6 seconds; Matrix, 319.5+/-16.5 seconds; P = 0.0002, paired t-test). Thirty-six percent of eyes with SITA VF defects showed a normal Matrix field. In 30 of 32 eyes (94%) where both devices showed VF defects, the defects were congruent. Mean threshold value was significantly lower with Matrix compared to SITA (P<0.0001, paired t-test), as was MD (-5.34+/-5.42 dB, -4.14+/-5.29 dB, respectively; P = 0.03, paired t-test). There was no significant difference in PSD between the 2 devices (P = 0.78, paired t-test). Matrix delineated significantly smaller (P = 0.005, Wilcoxon's test) and deeper (P<0.001, Wilcoxon's test) defects than those found with SITA. Similar results were observed in the subgroups with prior SAP experience.
CONCLUSIONS: The Matrix examination did not detect 36% of abnormal SITA fields. Matrix field defects were smaller and deeper than those appearing in SITA perimetry.