is a deficiency in color perception. About 8 percent of men and 5
percent of women are affect by this disorder. People who are colorblind
either are missing specific types of cones or their cones do not work properly.
the deficiency occurs in the red receiving cones (protanopia) or the green-receiving
cones (deuteranopia). Occasionally, there will be a problem with
the blue receiving cones, but this is much more rare. Colorblindness
can develop as a symptom of certain diseases or as a side effect of some
medications, but it is usually inherited and present at birth.