by Barbara Stanley

Created on: January 26, 2009   Last Updated: March 05, 2011

Color blindness is a malfunction of the retina, which converts light energy into electrical energy that is translated to the brain. It is extremely rare for someone to be totally color blind. Most people actually have a form of color deficiency. There are several types of color deficiency. The person may tell another that he is color blind, but this does not necessarily mean that he sees no color at all. He may not be able to tell red from green or blue from purple, but he sees colors.

There are different types of color deficiency:  Anomalous Trichromacy - A mild shift in the sensitivity of pigments of the cones in the back of the eyes: Protanomaly - shades of red appear weaker in  brightness; Deuteranomaly - shades of green appear weaker; Tritanomaly - very rare case where shades of blue appear weaker; Dichromacy - Great deficiency or missing completely one of the cones; Protanopia - shades of red are greatly reduced, if present at all, in brightness; Deuteranopia - shades of green are greatly reduced, if present at all, in brightness; Tritanopia - very rare case where shades of blue are greatly reduced, if present at all, in brightness. 

There are a few methods for Color Blindness testing. The most used is the Ishihara plates test. This test consists of plates that contain a circle filled with bubbles in shades of colors to be tested. In this circle is formed certain numbers that people with certain color deficiency will not be able to distinguish. To take a color blindness test and get a color scheme of different color deficiency, please visit http://www.iamcal.com/toys/colors/index.php.

Color blindness mainly affects males, although females are rarely affected. Females are usually carriers of the color blind trait, passing the condition to their male children. When females are color blind, they almost never have the rarest form in which no color is seen.

This author had a maternal grandfather who was totally color blind. He and his wife had thirteen children, six girls and seven boys. Four of the sons were color blind. Three of the girls were color blind. This author's mother is one of the color blind girls. Was it blind luck, pun intended, that she married a man who is totally color blind? What are the odds? I guess we will have to ask an expert. As it turned out, this author's parents had three sons and two daughters. The three sons are color blind and this author has a form of

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