title: Efficiency of the Ishihara test for identifying red-green colour deficiency.
abstract: The Ishihara test is the most widely used screening test for red-green colour deficiency. Results obtained by 401 people with red-green colour deficiency show that the combined sensitivity of the Transformation and Vanishing plates of the 38 plate Edition of the Ishihara plates is 95.5% on eight errors, 97.5% on six errors and 99.0% on three errors. The Hidden digit designs only identified approximately 50% of colour-deficient subjects. The protan/deutan classification plates were found to be more effective for deutans than for protans. No classification was obtained for 18% of protanopes and 3% of deuteranopes who saw neither figure on classification plates; 40% of protanomalous trichromats and 37.5% of deuteranomalous trichromats saw both classification figures and were classified on the relative luminance (clarity) of these figures. The specificity of the Ishihara test was determined in a previous study (Birch and McKeever, 1993) and the results combined with the present data to obtain the overall efficiency of the Ishihara plates for a representative cross section of colour-deficient subjects.
authors.affiliation: Department of Optometry and Visual Science, City University, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Birch
mesh_terms: D000328:Adult; D003119:Color Perception Tests / Q000379:methods*; D003117:Color Vision Defects / Q000145:classification / Q000175:diagnosis* / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D015351:Vision Screening / Q000379:methods