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I.E. Pacey, J.M. Wild, I.A. Cunliffe; Perimetric Fatigue Is Not Dependent Upon Threshold Algorithm . Invest. Ophthalmol. Vis. Sci. 2003;44(13):58.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: to evaluate the magnitude of the perimetric fatigue effect for the Full Threshold and SITA Standard algorithms in glaucoma and in age-matched normal subjects Methods:One eye of 20 patients with glaucoma and of 20 normal individuals underwent perimetry four times at each of two visits. At one visit SITA Standard and Program 30-2 were used. At the other visit the Full Threshold algorithm was used with, alternatively, one of two user-defined custom programs each comprising one separate half of the stimulus locations of Program 30-2. When combined, the two custom programs approximated to a complete Program 30-2 examination. The data were analysed in two separate ways in order to investigate the fatigue effect for 1) a similar examination duration and 2) a complete examination of the central visual field with each of the threshold algorithms. Results:For both analyses, the magnitude of the fatigue effect was similar for each of the two algorithms and was greater for the glaucoma group (approximately 1.51dB) than for the normal group (approximately 0.71dB). The fatigue effect exhibited a maximum at least within the first twelve to 15 minutes of perimetry. Conclusions:The perimetric fatigue effect was independent of the algorithm used to estimate threshold. The previously reported higher sensitivity and reduced between-subject variability for SITA Standard compared with Full Threshold cannot therefore be attributed to fatigue. The narrower confidence limits of normality for SITA may result in the fatigue effect reaching greater statistical significance on probability analysis.
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