What is Color Blindness?
- Color blindness – A condition where a person has a deficiency with color vision – this is mostly an inherited condition and there are certain colors a person cannot distinguish from another. If a person is inflicted with the most common Red/Green form of color blindness they have difficulty telling the difference between shades of red and green colors. This form represents 99% of color blindness. The other form of color deficiency is Blue/Yellow. This form of color blindness is not common and testing is difficult to obtain.
- Red/Green color blindness inflicts about 12% of boys and 1% of girls. Shades of gray color blindness, a.k.a. totally color blind, is very rare.
- No treatment exists today to minimize the condition or to reverse color blindness.
- Contrary to popular belief, being color blind does not mean a person sees the world in black, white, or gray shades, rather, just some colors get confused. It is rare for this to occur.
- Color sensitive receptors are located in the eye called cones; contain blue, green, and red light. Each of the cones contain vision pigments that when reduced or one of the color cones is missing, color vision is disrupted. The X chromosome carries the gene for color blindness; since a boy has X-Y, color blindness is more prominent than in girls who have X-X chromosomes.
- Encoding colors is the responsibility of cones. Each cone consists of visual pigments or structures that are sensitive to either a green, blue, or red wavelengths of light. Normal people have the ability to appropriately use a mixture of just three of the fundamental colors and their sensitivities. People see so many colors because of the response the cone cells have to wavelengths of light’s of different compositions.
- The levels of red and green deficiencies vary per individual and blue color deficiency is rare.
- Color blindness is tested and detected by using a common test called the Ishihara Color Test.
How Does Color Blindness Work?
- Light coming into the eye and resting on the retina is how the human eye is able to see images. The retina contains many Cones and Rods. The cones are located in the central part of the retina; this is call the macula, and is good during daylight vision for viewing colors. The rods are what allow a person to have night vision, but are no use for seeing colors.
- People having normal color vision and cones see different colors (all) and any mixture of colors; this is achieved by cones utilizing light wavelengths, one of three; green, blue, and red.
- If one or more of the three cones does not function well, mild color deficiency can result. If even one of the cones stops functioning all together or isn’t present, then the color deficiency can be poor.