What causes color blindness?
There are two types of color blindness. The most common is red-green color blindness, the less common form is blue color blindness. Both are cause by defective genes that control the production of rods in the retina. (Rods are the light sensors that allow us to see color.) In the case of red-green color blindness, the defective gene is found on the X chromosome and cause the red and green rod to respond to the same wavelengths of light. This gene is also recessive. Therefore, as long as the individual has a normal gene, they will not be color blind. Because of this, red-green color blindness is far more common among men than it is women. Since men only have one X chromosome, they have not backup if they inherit the defective gene. Since it is the x chromosome that carries this gene, the man inherits the condition from his mother and will bass the defective gene on to any daughters that he may father. However, he won’t pass it on to any of his sons. In order for a woman to inherit this
Color blindness is most often a genetic visual deficiency that limits the colors that an individual can detect. Color blindness that results in black and white vision is extremely rare. The colors affected are usually limited to green and red, which often appear as shades of tan or brown. Less often, the color blue may also be affected. The human eye detects color with photoreceptors located on the retina at the back of the eye. These photoreceptors come in two types, rods and cones. Rods fill the peripheral edges of the retina and are used in low-light conditions, such as in night vision. Rods do not detect color well, but allow people to see in the dark. Cones appear throughout the retina and contain pigments that are responsive to certain colors. The pigments communicate with the brain when fired. This is how a person detects color. Cones require brighter light to function than do rods, which is why we cannot see colors well in the dark. Color blindness is a result of certain cones
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. More men than women have color blindness. And usually people with a color deficiency are born with it. Photoreceptors in the retina include rods that enhance vision in low lighting, and cones that help us see in color vision. Inherited forms of color blindness often are related to deficiencies in certain types of cones or outright absence of these cones.
Most color vision problems are inherited (genetic) and are present at birth. Other color vision problems are caused by aging, disease, injury to the eye (acquired color vision problems), optic nerve problems, or side effects of some medicines. Inherited color vision problems are more common than acquired problems and affect males far more often than females.
The retina contains rods and cones that help us to see objects in different colors and varying degrees of brightness. The cones are photoreceptors that allow us to distinguish between many colors and different shades of these colors as well. The cones contain light sensitive pigments that are particular to range of range of wavelengths. There are three different types of cones with one sensitive to short wavelengths, or the color blue, one sensitive to medium wavelengths, or the color green , and the other sensitive to higher wavelengths, or the color red . When there are deficiencies in the cones, either at birth or acquired through other ways, the cones are not able to distinguish the particular wavelengths and thus, that color range is seen differently. Missing the cones responsible for green and red hues can also affect the sensitivity to brightness. Color blindness is hereditary and thus it is usually transferred at birth. As we age our sensitivity also diminishes as well but usua
