Imagine going through life with no perception of color; unable to recognize the color of the sunrise, fruit, the sky, water, flowers, etc. It's difficult to imagine such an existence, especially for those persons who were previously able to identify such colors, but, as a result of a trauma or other condition, are now unable to.
Color, however, serves more than an aesthetic purpose. It helps us to identify and classify objects. For example, a red traffic light indicates that we should not proceed through an intersection and the color of a banana helps us to determine how ripe it is. In addition, color perception aids us in indentifying one object from another and selecting objects when they are surrounded by numerous other objects. For example, an individual who does not suffer from color blindness can easily detect a strawberry amid a selection of other fruit or a bed of lettuce.
There are four basic colors: red, yellow, green and blue. Other colors are created by mixing colors (i.e., purple is created by mixing red and blue). Still other colors are created by modifying the intensity to make colors brighter or dimmer. In all, humans can distinguish between approximately 200 different colors.
Many individuals suffer from a condition known as color deficiency, which is a partial loss of color perception and is associated with problems with the receptors in the retina. There are three types of color deficiency: Monochromat, Dichromat and anomalous trichromat. Monochromatism is rare and is hereditary. In addition, persons with this condition have a sensitivity to light and have to wear dark glasses during the day to protect their eyes. Dichromats can perceive some colors, and can be categorized into three forms: protanopia, deuteranopia and tritanopia.
In essence, color is an important property which aids in our survival and enjoyment. However, persons who experience conditions in which they are not able to perceive color learn to adapt in order to acclimate to their new environment absent color.