Cambridge Colour Test

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The Cambridge Colour Test for ViSaGe provides a rapid means of screening subjects for colour vision deficiencies. It can also be used to examine in more detail the changes in colour discrimination that occur as a result of congenital or acquired conditions. The test was developed by Professor John Mollon and his colleagues (Department of Experimental Psychology, University of Cambridge) and determines discrimination ellipses in colour deficient subjects by probing chromatic sensitivity along the colour confusion lines. Ellipses measured in individuals with even slightly anomalous colour vision are characteristically orientated and enlarged. The test is an ideal tool for monitoring quantitatively over time the progression or remission of disease. Many drugs affect colour vision and pharmacologists will find the test well suited to monitoring the short-term or long-term course of such side-effects.

The price below is for the Cambridge Colour Test for Visage, software only. You will also require a ViSaGe and other hardware. For a complete ready to run system including the Cambridge Colour Test plus Low Vision Colour Test, Visual Acuity, and Spatial & Temporal Contrast Sensitivity Function see Metropsis.

Guide Price: £1000

SKU: M1401

Investigate the limits of colour discrimination

The Cambridge Colour Test provides a rapid means of screening subjects for colour vision deficiencies; but it also can be used to examine in more detail the changes in colour discrimination that occur as a result of congenital or acquired conditions. It allows the investigator to monitor quantitatively over time the progression or remission of disease. Many drugs affect colour vision and the pharmacologist will find the test well suited to monitoring the short-term or long-term course of such side-effects.

The test determines discrimination ellipses in colour deficient subjects by probing chromatic sensitivity along the colour confusion lines. Ellipses measured in individuals with even slightly anomalous colour vision are characteristically orientated and enlarged (see references).

Easy to use

The procedure is easy to use for both the investigator and the subject. It uses the familiar Landolt C stimulus, defined by the two test colours that are to be discriminated, on an achromatic background.

The Cambridge Colour test uses the proven concept of introducing spatial and luminance noise into the stimulus, which is composed of grouped circles randomly varying in diameter and having no spatial structure. The Landolt C is therefore defined by chromaticity alone, ensuring that the subject's responses are not due to luminance or spatial cues in the stimulus, and thus avoiding the necessity for a preliminary procedure to find isoluminance for the test colours.

The test is conceptually very simple to explain to the subject, who responds to the orientation of the Landolt C using the 4-button infra-red response box. The chromaticity of the components of the C is varied along the protan, deutan and tritan lines (or other chromatic axes if desired) using a standard descending psychophysical staircase procedure.

The importance of stimulus resolution

The 8 bit output resolution of conventional computer graphics systems offer too coarse a resolution for measuring the limits of human colour discrimination. The stimuli are produced by ViSaGe, which provides 14 bit colour and luminance control and is calibrated using a ColorCAL. Cambridge Colour Test can therefore provide a finely graded measurement of discrimination and allows small changes to be monitored over time or in different experimental conditions.

Proven

The Cambridge Colour Test is an established method and has been widely used for both clinical and basic research including an extensive normative data set. (see references).

Results

Results are saved in ASCII format and presented graphically as discrimination ellipses in CIELUV or CIE(x,y) colour space. The results shown are typical of a subject with normal colour vision; in deficient subjects the discrimination ellipses are significantly extended in the protan, deutan or tritan chromaticity directions.

 

References

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