Color distinction or the innate ability to judge the subtle differences featuring different colors is one of the finest perceptions of humans. Color blindness is either partial or impartial inability to take note of color distinctions despite the presence of light. Eye with its 'retinal cones' makes for the color perception. Faulty development of color distinguishing retinal cones accounts for color blindness. It is to be borne in mind that people with color blindness can see colors, but is unable to take note of the subtle differences. Test for color blindness also known as "Color vision test" serves to throw light on this distinguishing ability.

Color blindness occurs when light-sensitive cells in the retina fail to respond appropriately to variations in wavelengths of light that enable people to see an array of colors. Photoreceptors in the retina are called rods and cones. Rods are more plentiful (there are approximately 100 million rods in the human retina) and they are more sensitive to light, but rods are incapable of perceiving color. The 6 to 7 million cones in the human retina are responsible for color vision, and these photoreceptors are concentrated in the central zone of the retina called the macula. The center of the macula is called the fovea, and this tiny (0.3 mm diameter) area contains the highest concentration of cones in the retina and is responsible for our most acute color vision.

1. Impairment in the way of retinal development, affecting its color distinguishing cones leads to color blindness.
2. Genetic distribution is one of the principal causes of color distribution.
3. Heredity has a part to play as well and so many a time you can inherit it from your predecessors.
4. Besides the reasons of heredity and that of genetic distribution, color blindness can also result from causes of injury.
5. Physical injury to eye or its associated nerve endings can bring about color blindness
6. Damage to brain can be one of the causative factors.
7. The subtle ability for color distinction can also take place with age.
8. Diseases affecting the neural aspects of eyes including their optic nerves can result in color blindness.