• We compared the traditional intuitive criterion (fixed at 5 dB) with the variable Statpac 2 criterion of the Humphrey Field Analyzer for identifying visual deterioration at individual points within a visual field. The separation of depressed from stable points in 123 follow-up fields of 17 patients, when all points within a field were considered, was reasonably equivalent between the two methods (k = 0.55 ± 0.027 [± SE]). Centrally located points within the field demonstrated a stronger agreement (k = 0.68 ± 0.028), because the fixed criterion more often labeled the edge points as having progressed than did the Statpac 2 algorithm. The glaucoma change probability printout is more simply obtained than the manual comparison required for intuitive interpretation with a fixed criterion, and it is potentially more accurate because of its reliance on a database that permits a variable criterion to be applied.
Morgan RK, Feuer WJ, Anderson DR. Statpac 2 Glaucoma Change Probability. Arch Ophthalmol. 1991;109(12):1690-1692. doi:10.1001/archopht.1991.01080120074029