The City University test (also known as TCU test
or CU test
) is a
color vision test
A color vision test is used for measuring color vision against a standard. These tests are most often used to diagnose color vision deficiencies ("CVD"; color blindness''), though several of the standards are designed to categorize normal color vis ...
used to detect
color vision deficiency
Color blindness, color vision deficiency (CVD) or color deficiency is the decreased ability to color vision, see color or differences in color. The severity of color blindness ranges from mostly unnoticeable to full absence of color percept ...
. Unlike commonly used
Ishihara test
The Ishihara test is a color vision test for detection of red–green color deficiencies. It was named after its designer, Shinobu Ishihara, a professor at the University of Tokyo, who first published his tests in 1917.S. Ishihara, Tests for c ...
, City University test can be used to detect all types of color vision defects.
Description
The commonly used
Ishihara test
The Ishihara test is a color vision test for detection of red–green color deficiencies. It was named after its designer, Shinobu Ishihara, a professor at the University of Tokyo, who first published his tests in 1917.S. Ishihara, Tests for c ...
is used to detect mainly congenital red-green color blindness, but its usefulness is limited in detecting acquired color vision deficiencies.
But City University test contains test plates that can be used to detect all types of color vision deficiencies.
The TCU test was derived from Farnsworth D15 color arrangement test.
The test consists of 10 plates, containing a central colored dot surrounded by four peripheral dots of different colors. The subject is asked to choose the dot closest to the central hue. Among the four peripheral dots, three peripheral colors are designed in such a way that, it makes confusion with the central color in
protan,
deutan and
tritan deficiency.
The fourth color is an adjacent color in D-15 sequence
and that would be most similar to the central color.
Procedure
In a well illuminated room, hold the test plates at about 35 cm from patient. Show the test plates and ask the patient to mention which dot is identical to central dot. Allow about 3 seconds for each page. In response to the scores noted in score sheet abnormality can be detected.
See also
*
Color vision
Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different frequencies independently of light intensity.
Color perception is a part of the larger visual system and is mediated by a co ...
*
Color vision deficiency
Color blindness, color vision deficiency (CVD) or color deficiency is the decreased ability to color vision, see color or differences in color. The severity of color blindness ranges from mostly unnoticeable to full absence of color percept ...
References
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Optometry
Color vision
Diagnostic ophthalmology