PREVENT-BLINDNESS-AMERICA VISUAL-FIELD SCREENING STUDY

PURPOSE: To assess the screening efficacy and practical use of two por table devices to detect moderate to severe visual field loss rapidly i n population screening. METHODS: Henson visual field analysis and Dama to campimetry for glaucoma were performed in a healthy adult populatio n, to determine false-positive rates; in established glaucoma patients and suspects, to determine false-negative rates; and in a general adu lt population, to assess practical use in actual screenings. RESULTS: There were no false-positive test failures among the 82 normal subject s who completed the Henson two-step screening. Eighty of 83 normal sub jects passed Damato campimetry, resulting in a false-positive rate of 3.6%. Among 83 glaucoma suspects and patients, the Henson test identif ied 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 held loss, The Damato campimeter detected 55 (81%) of 68 subje cts 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 s ubjects tested in general population screenings, 55 subjects (4.3%) fa iled either or both tests. CONCLUSIONS: The Henson visual field analyz er can discriminate moderately to severely dis eased from normal visua l fields with high sensitivity and specificity. The Damato campimeter can reliably detect moderate to severe visual field loss with a tolera bly low false-positive rate. To overcome the weakness of glaucoma scre ening by tonometry alone, some forms of visual field testing may be ac ceptably brief (cost effective) and accurate (sensitive and specific).