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. © 1997 The College of Optometrists. Published by

Colour–coolant–aroma interactions and the impact of congruency and exposure on flavour perception

“…All subjects presented no taste or olfactory deficits and they had normal or superior colour vision discrimination according to the Farnsworth-Munsell 100 Hue Test (GretagMacbeth Ltd., Preston Brook, UK) and Ishihara test (Birch, 1997). Moreover, they presented no hearing deficiency at 4000 Hz (Hou & Dai, 2004).…”

A lantern color vision test for the rail industry

“…As Birch [1997] states, many of the errors made by the color-normals on the Ishihara test are not usually typical of errors made by color-defectives and an experienced clinician would not have much of a problem interpreting their results. However, the FRA uncovered problems by interpreting the patients' responses and concluded``it may not be prudent to allow examiners any discretion in interpreting a patient's response.''…”

“…The reason for this comparison is that the FRA criteria for passing most editions of the Ishihara test are more stringent than typically recommended for clinical use. The FRA failure criterion for all editions is errors on over 18% of the screening plates, whereas others allow errors ranging from 23% to 38% [Hackman and Holtzman, 1992;Johnson, 1992;Birch, 1997]. For the 38 plate edition of the Ishihara test, these percentage scores translate into four or more errors for the FRA as compared to values ranging from ®ve to eight or more errors for the others.…”

“…Previous studies suggest that the number of false positives in the color-normal population could range from 1 to 6% using the FRA guidelines [Hackman and Holtzman, 1992;Johnson, 1992;Birch, 1997]. In addition, our preliminary work suggests that about 1% of the color-defective population as well as colornormals can perform on a ®eld test and these individuals would also be excluded from the position of a locomotive engineer [Hovis and Oliphant, 1998].…”

Ishihara test in 3- to 6-year-old children

“…This test is known to have excellent sensitivity and specifi city for screening purposes. 2,3 Because of problems concerning the availability and suitability of new color vision tests for young children and individuals with low cognitive ability, we undertook to reevaluate the effi cacy of the Ishihara test in preschool children.…”