Causes of Color Blindness and How Does it Happen
By Jannah J Smith
During college days, I remembered when we took the college
entrance examination. A friend of mine did not pass the physical
exam of the school because he is color blind. How could this
happen? Is it possible that a person is color blind? Let me first
discuss what color blindness is. Color blindness or color vision
deficiency is the inability of a person to know the differences
between some colors.
Color blindness is due to a default gene and it can also occur due to eye, nerve and brain damage or exposure to chemicals. A chemist named John Dalton, a color blind conducted a study about color blindness. Because of his work, the condition was named Daltonism. This term is now referred to as Deuteranopia. It is classified as a mild disability. There are situations that color blind individuals have an advantage over those that have normal color vision because they can better penetrate certain color camouflages.
The human retina has two kind of light cells. The rod cells that is active in a low light and the cone cells that are active in a normal day light. In a normal eye, there are three kinds of cones that contain different pigments. These pigments are activated when it absorbs the light. The absorption capacity of the cones differ, one is sensitive to a short wavelength, one to a medium wavelength and the other one to a long wavelength. The absorption capacity of these three systems covers much of the visible spectrum.
Different colors are recognized when the different types of cones are being stimulated to a different degree. For example, a red light stimulates the long wave length cones. When the wave length is reduced, the other two cones are stimulated increasingly that causes the change of color to blue. The gene that is involved in color vision is the X chromosome. Color blindness is more common in males than females because of the fact that males have only one X chromosome while females have two.
Color blindness can be inherited and can be congenital. Individuals that are color blind since birth can be color blind for the rest of his life depending on the mutation. In some cases, certain color blindness can progress to legal blindness and sometimes a person will totally become blind.
Color blindness is due to a default gene and it can also occur due to eye, nerve and brain damage or exposure to chemicals. A chemist named John Dalton, a color blind conducted a study about color blindness. Because of his work, the condition was named Daltonism. This term is now referred to as Deuteranopia. It is classified as a mild disability. There are situations that color blind individuals have an advantage over those that have normal color vision because they can better penetrate certain color camouflages.
The human retina has two kind of light cells. The rod cells that is active in a low light and the cone cells that are active in a normal day light. In a normal eye, there are three kinds of cones that contain different pigments. These pigments are activated when it absorbs the light. The absorption capacity of the cones differ, one is sensitive to a short wavelength, one to a medium wavelength and the other one to a long wavelength. The absorption capacity of these three systems covers much of the visible spectrum.
Different colors are recognized when the different types of cones are being stimulated to a different degree. For example, a red light stimulates the long wave length cones. When the wave length is reduced, the other two cones are stimulated increasingly that causes the change of color to blue. The gene that is involved in color vision is the X chromosome. Color blindness is more common in males than females because of the fact that males have only one X chromosome while females have two.
Color blindness can be inherited and can be congenital. Individuals that are color blind since birth can be color blind for the rest of his life depending on the mutation. In some cases, certain color blindness can progress to legal blindness and sometimes a person will totally become blind.
Janna contributes to many free article directories and is a paid
staff writer for
FreeArticleDigest.com, where you can find articles on subjects ranging from wood file cabinets [http://www.freearticledigest.com/computers-and-office/woodfilecabinets.html] to stackable storage bins [http://www.freearticledigest.com/home-and-garden/stackablestoragebins.html]. You may republish this article free of charge, anywhere online, as long as all keyword links are left intact.
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