EVALUATION OF THE HUMPHREY-FASTPAC THRESHOLD PROGRAM IN GLAUCOMA

The makers of the Humphrey perimeter have developed a rapid thresholdi ng program, FASTPAC, to address the problems of fatigue and poor test performance associated with, prolonged perimetry. The performance of F ASTPAC was compared with the standard threshold program of the Humphre y visual held analyser (program 24-2) in 44 glaucoma patients. FASTPAC reduced the mean test time by 35% (from 12.6 to 8.2 minutes), owing t o a reduction in the number of stimulus presentations. FASTPAC underes timated the mean deviation (MD) (Wilcoxon, p = 0.007) and corrected pa ttern standard deviation (CPSD) (Wilcoxon, p = 0.005). The sum of the differences between FASTPAC and the standard program was -1.19 (SD 2.3 7) dB for MD and 0.97 (2.14) dB for CPSD. The measured difference betw een the two methods was independent of the value of either MD or CPSD, indicating that the measurement error was just as likely to occur wit h either early or advanced visual held loss. No difference was noted i n short term fluctuation or in the reliability indices of test perform ance. These results indicate that FASTPAC, while considerably faster, is not as accurate as the standard threshold program at measuring reti nal sensitivity in glaucoma. This inaccuracy may be offset in practica l terms by greater patient acceptability and by increasing the number of patients capable of performing reliable threshold perimetry because of the reduction in duration of the FASTPAC program.