Static threshold visual field in glaucoma with the Fastpac algorithm of the Humphrey Field Analyser. Is the gain in examination time offset by any loss of information?

A new algorithm (Fastpac) has been designed to speed up full threshold tests with the Humphrey Field Analyser. We studied the utility of this algorithm by comparing central 24-2 threshold programs obtained with standard and Fastpac algorithms in 43 hypertensive or glaucomatous eyes. The Fastpac reduced testing time by 35% to 45%. In glaucomatous eyes, the time spared was inversely correlated with the degree of visual field impairment. Global indices were used to compare visual fields. Mean absolute differences in indices did not exceed 0.98 dB. Correlations between indices in glaucoma patients with standard and Fastpac strategy were respectively 0.99 and 0.98 for mean deviation and pattern standard deviation. The intra-test variability (short-term fluctuation) was slightly higher with Fastpac with a lower correlation between algorithms (r = 0.62). The use of Fastpac achieves a mean time reduction of 40% and does not significantly modify global indices obtained with the Humphrey perimeter in hypertensive and glaucomatous eyes.