color

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color

 [kul´er]
1. a property of a surface or substance due to absorption of certain light rays and reflection of others within the range of wavelengths (roughly 370 to 760 nm) adequate to excite the retinal receptors.
2. radiant energy within the range of adequate chromatic stimuli of the retina, i.e., between the infrared and the ultraviolet.
3. a sensory impression of one of the rainbow hues.
primary c's a small number of fundamental colors. In visual science this refers to red, green, and blue, the colors specifically picked up by the retinal cones; mixtures of varying proportions of the primary colors will yield the 150 discriminable hues of normal human vision. In painting and printing, the primary colors are red, blue, and yellow.
color vision deficiency inability to distinguish between certain colors, popularly called “color blindness.” A complete deficiency (monochromatic vision), the total inability to see colors, is rare, affecting only one person in 300,000. Much more common are the various types of partial deficiency. The most common is red-green confusion (see deuteranopia and protanopia), which affects approximately 8 million people in the United States.

Color vision is a function of the cones in the retina of the eye, which are stimulated by light and transmit impulses to the brain. It is now thought that there are three types of cones, each type stimulated by one of the primary colors in light (red, green, and blue or violet). In red-green color vision deficiency, there is a deficiency of either red or green receptors, so that the two colors do not appear distinct from each other.

Color vision is usually tested by the ishihara test with a series of pseudoisochromatic charts or plates. (See Atlas 4, Part F.) These have a letter, number, or symbol printed in dots of one color in the midst of dots of gray or other colors. The normal person can see the symbol with no difficulty, but the person with color vision deficiency cannot distinguish it from the background.

Although color vision deficiency may occasionally result from injuries, diseases, or certain drugs, most cases are hereditary. It is usually inherited by males through the mother, who carries the trait from her father although she is not color deficient herself. In some cases, if the grandfather is color deficient and the mother carries the trait, a daughter may inherit color vision deficiency, but the ratio of men to women with inherited forms is about 20 to 1. There is no known cure for color vision deficiency.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

col·or

(kŭl'ŏr),
1. That aspect of the appearance of objects and light sources that may be specified as to hue, lightness (brightness), and saturation.
2. That portion of the visible (370-760 nm) electromagnetic spectrum specified by wavelength, luminosity, and purity.
[L.]
Farlex Partner Medical Dictionary © Farlex 2012

col·or

(kŭl'ŏr)
1. That aspect of the appearance of objects and light sources that may be specified as to hue, lightness (brightness), and saturation.
2. That portion of the visible (370-760 nm) electromagnetic spectrum specified as to wavelength, luminosity, and purity.
Synonym(s): colour.
[L.]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Patient discussion about color

Q. Why is the color draining from my eyes?! When I was little I had rich shiny cobalt blue eyes! As I grew up they faded or just started to dim in color. Being partially blind you can see in my left eye the its a really light color and creamy instead of my deep blue color... Why does my eye color dim?! I didnt think going blind had anything to do with the color of my eyes changing... Or is it something else?! Please, and thank you!

A. depends on your blindness, if it is caused by your cornea changing (corneal opacity)- it'll change your eye color to a cloudy white. it can also be caused by cataract.
are those the reason of your blindness?

Q. If someone as alcoholism do there eyes change color? My husband says his work mate told him that if you’re an alcoholic your eyes can change color. As an example If you have blue eyes they become a darker blue because of something in your bloodstream?. I think my husband’s workmate is winding my husband up, or is he telling the truth?

A. That is an untruth. The color of the eyes in an alcoholic will not change color. The only thing in the eyes that will change color are the corneas (the whites of the eyes) they will turn yellow due to jaundice and probably cirrhosis of the liver. The skin will also turn yellow with the jaundice.

Q. What exactly is PPD? I heard it is a substance in hair color and that some women are allergic to it How can I know if I’m allergic to it?

A. That sounds nasty... so how can I know if i'm allergic to it or not?

More discussions about color
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References in periodicals archive ?
crotalifera have been introduced in the floriculture business mainly differentiated by the size and pigments colouration of bracts.
In this case, severe black colouration of the articular cartilage appears to have occurred due to haemosiderosis and lipofuscin deposition on the articular cartilage.
In none of the specimens the shell colouration is preserved around the entire shell circumference, but the combined observations of all the specimens suggest that bands originally circumscribed the shell surface.
monalisa could be found there again, and, if so, whether there was any change from the mostly copper colouration observed in late August 2013.
The region from between the approximate latitudes 51[degrees]N to 59[degrees]N showed a noticeable warm or reddish colouration. The northern edge of this region was marked by a dark belt.
University of St Andrews researchers monitored diet in 35 people, finding more colouration in those who eat more greens in their diet, BBC health reported.
During the first three years of the survey (2000-2002), all specimens collected were of the "typical" colouration that is found in eastern southern Africa, being black with cream or blue-grey markings on the body (Figs 1-3, 5).
"While some change owners for a few pounds, rare ones with what we described as mutated colouration can go for thousands of pounds these days, so it is fatuous to deny that it is a business.
The Kori Bustard is a large bird with mottled grayish-buff colouration, dark brown vermiculation, and a distinct white stripe over each eye.
At week 2 the Polygonum group had black colouration in the regrowing hair, while neither less visible hair growth nor black colouration was observed in the control group.
[Beta] - carotene 10% CWS Star - a high performance and natural-source [Beta] - carotene formulation for the colouration and fortification of food and beverages.