Survey of the accuracy of new pseudoisochromatic plates

Abstract

The accuracy of three new pseudoisochromatic tests for detecting red-green colour deficiency was assessed. These were the Ishihara plates, the Ishihara test for 'unlettered persons' and Ohkuma's test cards. We examined 500 subjects; 471 normal trichromats and 29 colour-deficient people. Results obtained for the 1989 edition of the Ishihara plates were compared with the 9th edition and the most efficient plates identified. Although normal trichromats may be expected to make several interpretive misreadings, the Ishihara plates were found to be superior to the 9th edition and to the Ohkuma test (1986) for colour vision screening. The new symbol designs of the Ishihara plates for 'unlettered persons' (1990) were found to be very effective for colour vision screening, and a further study with young children is proposed. The 38 plate 1989 edition of the Ishihara test is recommended for use in clinical practice. The designs included in the concise 24 plate edition and the new abbreviated 14 plate edition are not selected from the point of view of accuracy and more reliable results are obtained if the full test is given or if the practitioner shows only the most efficient designs.

Assessing the Severity of Color Vision Loss with Implications for Aviation and Other Occupational Environments

“…as an example of a non-typical error, has been described previously and such confusions are more likely to occur when weak color signals are involved (7,9,12). Birch and McKeever have described non-typical errors made by normals as ''misreadings" -as a partial filling up of serif design of the digits of the IT, for example a '5' may be interpreted as a '6', or '3' as '8' (7). Although such factors may well contribute to a 'misreading', these factors apply equally well to subjects with congenital color deficiency in the context of a numeral defined by weaker and often different chromatic signals.…”

“…Transformation or confusion: plates 2-9 -normal trichromats and subjects with color vision deficiency read different numbers. as an example of a non-typical error, has been described previously and such confusions are more likely to occur when weak color signals are involved (7,9,12). Birch and McKeever have described non-typical errors made by normals as ''misreadings" -as a partial filling up of serif design of the digits of the IT, for example a '5' may be interpreted as a '6', or '3' as '8' (7).…”

“…Currently three versions are available: the full version containing 38 plates, the abbreviated version with 24 plates and the concise version containing 14 plates. The full version has been recommended for routine clinical use (7), albeit the abbreviated and concise versions being subsets of the full version. In the full version, the first 25 plates contain numerals (single or double digit numbers) which have to be named verbally, whereas the remaining plates have pathway designs intended for examination of nonverbal subjects and are rarely used.…”

Colour Vision in Stargardt Disease

“…In this study we used a combination of the Ishihara and HRR PIC plates because their functions are complementary [41]. Sensitivity and specificity of the Ishihara test for the detection of congenital R/G CVDs are close to 100%, which is why this test should be included in the basic battery of tests for the assessment of colour vision in clinical practice, especially if anomaloscopy is unavailable [42,43]. An important limitation of the Ishihara test is that it provides no useful information about the severity of the colour vision defect, since the number of errors in the Ishihara test is not a measure of severity, and the intended classification of the type of R/G deficiency using the classification plates is not always achieved [29,42,44].…”

A study on differences in human perception between a real and an AR scene viewed in an OST‐HMD

“…Before the formal experiment, all the participants have performed visual function tests, including the visual acuity test, the stereo acuity test, and the Ishihara test to ensure that they have normal or correcting normal vision functions. As a result, 18 participants (nine males and nine females) have passed the tests and could participate in the experiment.…”