Abstract
Purpose::
To compare the new GATE algorithm, which is independent of test point arrangement and applicable to any kind of visual pathway lesion, with SITA and with the conventional 4-2-1 dB thresholding procedure with regard to local differential luminance sensitivity (DLS), retest reliability (RR) and examination time (ET).
Methods::
Four perimetric strategies were carried out in partially randomised order in each of two visits: a conventional 4-2-1 dB thresholding procedure (O-421), an initial session applying the GATE strategy (GATE-i), a regular, subsequent GATE strategy (GATE), each performed on the Octopus 101 perimeter (Haag-Streit, Koeniz, Switzerland), and the SITA standard strategy, using the HFA II instrument (Carl Zeiss Meditec, Jena, Germany). Stimuli (size III = 26') were arranged in a conventional 24-2 grid and presented on a background luminance of 10 cd/m² in all sessions.Thirty-six eyes of 36 subjects (16 females, 20 males; age range 27 through 85 years), 9 with OHT, 9 with suspected glaucoma and 18 with manifest glaucoma were enrolled in this study until 11/2006.
Results::
DLS of GATE was systematically 2.1 dB (95% confidence interval [CI] 1.5 to 2.7 dB) higher than DLS of GATE and 0.4 dB (CI -0.4 to 1.0 dB) higher than DLS of O-421. DLS differences between GATE and SITA depended strongly on the local DLS level. Comparison between the strategies is probably hampered by the different dynamic ranges of the two perimeters. SD of differences between visits were 3.8 dB (2.7 dB) for O-421, 4.3 dB (3.2 dB) for GATE-i, 4.3 dB (3.5 dB) for GATE and 3.6 dB (3.1 dB) for SITA (values in brackets indicate SD of differences excluding absolute defects in any strategy). RR measured by median rank correlation of locations was 0.84 for O-421, 0.73 for GATE-i, 0.77 for GATE and 0.80 for SITA. ET was 9.1 min (95% reference interval [RI] 7.8 to 10.5 min) for O-421, 5.7 min (RI 4.3 to 7.5 min) for GATE-i, 4.7 min (RI 4.3 to 5.3 min) for GATE and 5.4 min (RI 4.0 to 7.3 min) for SITA.
Conclusions::
DLS values of the GATE strategy are comparable to those of conventional thresholding strategies. RR of GATE is lower than in conventional thresholding and SITA. ET for GATE is considerably shorter than for conventional thresholding and shorter than for SITA.
Keywords: perimetry • visual fields