Color Blindness is an inaccurate perceptual sensitivity to certain colors. Although there are many forms of Color Blindness, the most common form of color blindness is red and green deficiency or red-green deficiency. The person does not pick up red or green colors correctly.
At the back of your eyes you have Cones and Rods. Cones pick up color and Rods pick up brightness. There are blue cones, red cones and green cones. They pick up different wavelengths of light. Color blind people have less numbers of particular cones than normal, so they get colors confused. Some people are more color blind than others. In the case of a red-green color Deficient individual there are not enough red and green cones (In some cases no green cones at all. In that case the red cones can pick up some green) this does not mean that that person sees in black and white. It means that that person confuses red, green, and brown colors. But it also depends on the intensity of the color and the brightness of the light conditions at that time. This is the same in every other type of Color Blindness. For example, if a person has yellow-blue color blindness (second most common form) they would have the same problems only with yellow and blue colors rather than red and green.
Color Blindness is a hereditary disease. It is passed through by genetics. It is more common with males than females. One in twenty males are color blind. The reason why it is more common in males than females is because males only need one allele while a female needs two alleles. This is an example of sex linkage. Therefore it is more dominant in males rather than females. Also, Color Blindness occurs from diseases. Glaucoma and Diabetes are known to destroy vision. They reduce blood supply to the retina, even though the specific mechanisms are different.
Color blindness severely affects people's lives. Very few companies or services give color blind people any thought.