Prevent blindness America visual field screening study

PURPOSE: To assess the screening efficacy and practical use of two portable devices to detect moderate to severe visual field loss rapidly in population screening. METHODS: Henson visual field analysis and Damato campimetry for glaucoma were performed in a healthy adult population, to determine false-positive rates; in established glaucoma patients and suspects, to determine false-negative rates; and in a general adult population, to assess practical use in actual screenings. RESULTS: There were no false-positive test failures among the 82 normal subjects who completed the Henson two-step screening. Eighty of 83 normal subjects passed Damato campimetry, resulting in a false-positive rate of 3.6%. Among 83 glaucoma suspects and patients, the Henson test identified 49 (84%) of 58 subjects whose full-threshold fields from Humphrey perimetry were abnormal, 38 (97%) of 39 of whom had moderate to severe visual field loss. The Damato campimeter detected 55 (81%) of 68 subjects with any pathologic loss on full-threshold visual fields, 44 (92%) of 48 of whom had moderate to severe visual field loss. Among 1,278 subjects tested in general population screenings, 55 subjects (4.3%) failed either or both tests. CONCLUSIONS: The Henson visual field analyzer can discriminate moderately to severely diseased from normal visual fields with high sensitivity and specificity. The Damato campimeter can reliably detect moderate to severe visual field loss with a tolerably low false-positive rate. To overcome the weakness of glaucoma screening by tonometry alone, some forms of visual field testing may be acceptably brief (cost effective) and accurate (sensitive and specific).