Glaucoma follow-up when converting from long to short perimetric thresholdtests

Objectives: To study the influence of test length in automated perimetry fo llow-up of glaucomatous eyes and, particularly, to determine if it is possi ble to usefully interpret test results obtained using a testing algorithm s horter than that used for baseline testing. Methods: Automated perimetry findings were retrospectively evaluated in 31 patients with glaucoma for whom multiple Humphrey 30-2 tests were available on the Full Threshold strategy and the SITA Standard strategy. Results: Variability around the mean deviation regression lines was smaller with SITA than with the Full Threshold strategy. Mean deviation values wit h SITA averaged about 1 dB less severe. Although localized scotomas measure d in decibels were deeper on the Full Threshold strategy, number of signifi cantly depressed points on total deviation and pattern deviation probabilit y plot analyses did not differ significantly between the 2 strategies. Conclusions: The SITA strategy showed test-retest consistency that was at l east as good as that of the Full Threshold strategy. The 2 strategies produ ced similar results when analyzed relative to their respective normal signi ficance limits. Generally, it is appropriate to establish a new baseline wh en converting from one perimetric algorithm to another. When necessary, how ever, results may be usefully compared if such comparisons are based on tot al and pattern deviation probability maps rather than on decibel values.