The sensitivity and specificity of alternate analytic strategies for recognizing glaucomatous visual field loss from automated threshold perimetry (C-30-2 test of the Humphrey Field Analyzer) were compared among one eye each of 106 patients with glaucoma and 249 normal subjects. Algorithms included commercially available global indexes and cross-meridional differences (Statpac 1 and Statpac 2), as well as cross-meridional and cluster analyses that were developed independently for natural history studies and clinical trials. The sensitivity of most algorithms was high, except for those that used only diffuse loss as an indicator of abnormality. Specificity was acceptably high for all algorithms. Subjects who failed to meet the manufacturer's standard for reliability had much reduced specificity, but sensitivity was also affected. Algorithms that were based on any of the alternate definitions of localized reduction in retinal sensitivity performed equally well, which suggests that any of these approaches is useful in searching for glaucomatous visual loss as typified by this database. Availability, familiarity, and convenience may govern the selection of any one analytic approach for use in a particular setting.