Definition

Color blindness is a condition in which people have mild to severe difficulty identifying colors. Color blind people may not be able to recognize various shades of colors and, in some cases, cannot recognize colors at all.

Description

Normal color vision requires the use of special cells in the retina (the innermost lining) of the eye called cones. There are three types of cones—blue, green, and red—which allow an individual to recognize a large spectrum of colors. Cones sometimes do not function normally. When that happens, a person has trouble recognizing colors.

The three basic types of color blindness are as follows:

• Red/green color blindness. Red/green color blindness is the most common form of the disorder. It affects about 8 percent of all Caucasian (white) males and 0.5 percent of all Caucasian females. People with this disorder can distinguish red from green if...