Evaluation of FASTPAC, a new strategy for threshold estimation with the Humphrey Field Analyzer, in a glaucomatous...

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) double-staircase strategy.

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 using program 24-2, target size III. The order of strategy was randomized for each patient. The results were analyzed using analysis of covariance for a two-period crossover trial. Mean deviation, pattern standard deviation, short-term fluctuation, corrected pattern standard deviation, number of stimulus presentations, and examination time were analyzed separately; test sequence and severity of field loss were considered as between subject factors and age as a covariate.

The FASTPAC algorithm demonstrated a 36% saving in examination time (P < 0.001), 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 deviation (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 the standard full-threshold strategy (P = 0.033).

The FASTPAC strategy reduced the examination time but exhibited a decreased estimate of field severity and a greater intra-test variance.