SENSITIVITY, SPECIFICITY, AND PREDICTIVE VALUES OF SCREENING-TESTS FOR EYE CONDITIONS IN A CLINIC-BASED POPULATION

Purpose: To assess four commonly available visual function tests to de tect visually disabling or vision-threatening eye conditions among new patients of a large, urban, public, general ophthalmology clinic, Met hods: Three hundred seventeen patients were tested for contrast sensit ivity, Amsler grid abnormalities, and visual acuity at near and at dis tance, A complete eye evaluation found the prevalence of serious eye d iseases, allowing determination of the sensitivity (Sn), specificity ( Sp), likelihood ratio (LR), and other characteristics of each test, Re sults: Of 317 patients, most were Hispanic (77%), women (60%), and mid dle-aged (44 +/- 17 years). Normal findings were reported in 18%; refr active error in 43%; cataracts in 16%; glaucoma in 7.3%; and macular d egeneration in 4.1%. Near visual acuity of 20/40 or worse (Sn = 0.75; Sp = 0.74; LR = 2.8); and distance visual acuity testing of 20/30 or w orse (Sn = 0.74; Sp = 0.73; LR = 2.7) correlated significantly with oc ular disease, whereas contrast sensitivity testing (Sn = 0.62; Sp = 0. 41; LR = 1.1) and Amsler grid test (Sn = 0.19; Sp = 0.92; LR = 2.4) di d not. Test performance decreased when refractive errors were excluded and among those younger than 40 years of age relative to those 40 yea rs of age or older. Conclusion: Of the four screening tests studied, d istance and near threshold visual acuities as defined above were judge d to have the best correlations of an abnormal result with ocular dise ase, both including or excluding refractive error, Different combinati ons of tests did not result in more accurate detection of ocular disea se. More efficient screening tools for detecting ocular disease need t o be developed.