Procedures for Testing Color Vision Report of Working Group 41 (1981) / Chapter Skim
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4. Using Color Vision Tests
4. Using Color Vision Tests
Pages 81-94
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From page 81... ...
Tests that were developed to evaluate color vision were both practical and empirical. While the anomaloscope remains the only clinical method for precise diagnosis of the presumed genetic entities, many tests have been devised for quick, inexpensive, and efficient screening of the color-defective population Screening tests are used to identify individuals who may eventually require more extensive color testing.
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From page 82... ...
Diagnosis of Red-Green Defects Anomaloscopes may be used for diagnosis of red-green color vision defects. The anomaloscope is the only clinical instrument for diagnosis and classification of the presumed Genetic entities of dichromacy and to both simple and extreme anomalous trichromacy as defined by Franceschetti (1928)
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From page 83... ...
Evaluation of Acquired Color Vision Defects The detection and classification of acquired color vision defects may be accomplished by use of an anomaloscope combined with a test that measures chromatic discr imination. In addition, 8 to 10 percent of males with acquired color defects have a concomitant congenital color defect; the examiner should be alert to this possibility.
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From page 84... ...
The correlation is not perfect since chromatic discriminative ability varies widely among anomalous trichromats. The NSMRL test battery will not necessarily predict the performance of the defective observer on other color tasks (Kinney et al., 19791.
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From page 85... ...
If the screening test does not include blue-yellow Plates, the F: plate may be added. Quantification of Chromatic Discriminative Ability Typically it is not appropriate to use the number of errors on a screening plate test as a numerical indication of chromatic discriminative ability.
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From page 86... ...
The Farnsworth-Munsell 100-hue test has been used as a quantitative test of chromatic discrimination even though its designer, Dean Farnsworth, originally suggested only that observers could be specified as showing superior, average, or inferior chromatic discriminative ability. It is generally accepted that the test involves not only chromatic discriminative ability but also cognitive parameters, such as concentration, patience, and cooperation.
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From page 87... ...
is evaluated best by a field trial using real materials; the materials should be identical to those encountered in the job situation, and the type and level of illumination must be exactly replicated. TEST ADMINISTRATION: TRAINING PERSONNEL TO ADMINISTER TESTS The majority of clinical color vision tests are designed for use by personnel with minimal training in color vision testing.
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From page 88... ...
If necessary, an observer may use a hand-held ophthalmic lens for screening plates or ophthalmic trial frames for arrangement tests. The Nagel Model I and Neitz anomaloscopes have adjustments for focus.
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From page 89... ...
The majority of normal trichromats with minor color defect show generally poor color discrimination and will not only fail color screening tests but show abnormal error accumulations on discrimination tests. Rarely, normal trichromats will fail a screening test but show no other sign of color defect.
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From page 90... ...
The Pickford-Nicolson anomaloscope should offer fewer difficulties to bifocal wearers. Testing Children Children under 12 years of age offer special problems in color testing, since many of the tests require intellectual abilities that develop at different ages: screening tests require knowledge of the alphabet or numerals; arrangement tests require the concept of serial ordering.
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From page 91... ...
The Guy's Hospital color vision test contains design flaws that make it ambiguous and confusing to adults, and thus presumably equally confusing to children (Alexander, 1975~. The Matsubara test contains symbols of items that are familiar and important in Japanese culture (e.g., cherry blossoms)
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From page 92... ...
Arrangement tests, such as the FM 100-hue test and Farnsworth Panel D-15 (Salvia, 1969) , also offer difficulties and may reveal high incidences of apparent color defect.
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From page 93... ...
Attempts to cure color vision defects reached a peak during World War II because of the number of young men with red-green color defects who were eager to be accepted into the Navy, Air Force, and office training programs. Some of the alleged cures and remedies, none
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From page 94... ...
Because of the relative changes in lightness that the filter produces, the lens may help the color-defective observer to make chromatic discriminations and to pass some color vision tents. However, neither the X-chrom lens nor any of the other color vision cures and remedies that have been proposed can restore normal color vision function.
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