Full threshold vs. sita in normal individuals undergoing automated perimetry for the first time

R. B. Schimiti, R. R. G. Avelino, N. Kara-José and V. P. Costa

Glaucoma Service, University of Campinas, Londrina, Brazil

Purpose: To compare the Full Threshold and the SITA standard algorithms in normal individuals undergoing automated perimetry for the first time.

Methods: 54 normal individuals underwent visual filed examinations (30-2, Humphrey 750, San Leandro, CA, USA) using both the Full Threshold and SITA strategies. Individuals were randomized to start the examination with either Full Threshold or SITA. Only one eye per individual was randomly selected to be included in the study.

Results: The percentage of fixation losses and false negative responses were not statistically different in both groups (p>0.05). The false positive rate in the Full Threshold group (4.6 + 1.6%) was significantly higher than in the SITA group (2.3 + 3%) (p=0.006). The duration of the exam was significantly longer in the Full Threshold group (p<0.05). There were no significant differences in mean deviation (MD), pattern standard deviation (PSD), or glaucoma hemifield test (GHT) results (p>0.05). However, the number of points with p<5%, p<2%, or p<1% in the Pattern Deviation Probability Map were significantly higher in the SITA group (p<0.05).

Conclusion: Inexperienced normal individuals may show a higher number of suspect points in the Pattern Deviation Probability Map when the SITA strategy is employed, which is probably associated with the smaller inter-subject threshold variance observed with this algorithm.