EVALUATION OF FASTPAC, A NEW STRATEGY FOR THRESHOLD ESTIMATION WITH THE HUMPHREY FIELD ANALYZER, IN A GLAUCOMATOUS POPULATION

Purpose: A new fast strategy for the estimation of threshold, FASTPAC, has been introduced for the Humphrey Field Analyzer. The aim of this study is to evaluate the performance, in a glaucomatous population, of FASTPAC compared with the standard full-threshold 4-2-decibel (dB) do uble-staircase strategy. Methods: The sample consisted of 30 glaucoma patients experienced in automated perimetry, ranging in age from 26 to 84 years. One eye of each patient was examined with both strategies u sing program 24-2, target size II. The order of strategy was randomize d for each patient. The results were analyzed using analysis of covari ance for a two-period crossover trial. Mean deviation, pattern standar d deviation, short-term fluctuation, corrected pattern standard deviat ion, number of stimulus presentations, and examination time were analy zed separately; test sequence and severity of field loss were consider ed as between subject factors and age as a covariate. Results: The FAS TPAC algorithm demonstrated a 36% saving in examination time (P < 0.00 1), a lower mean deviation (0.91 dB) (P < 0.001), and a greater short- term fluctuation (0.64 dB) (P = 0.008). The differences in mean deviat ion (P = 0.015) and short-term fluctuation (P = 0.033) became greater with an increase in age. As the severity of the field loss increased, the short-term fluctuation increased (P = 0.043), and examination time was increased for the FASTPAC strategy, while it became shorter for t he standard full-threshold strategy (P = 0.033). Conclusions: The FAST PAC strategy reduced the examination time but exhibited a decreased es timate of field severity and a greater intra-test variance.