Sight & Hearing

Oct 2000

Colorblindness is probably the least recognized and most ignored of all vision defects

The cone cells at the center of the human retina determine the perception of color during daylight conditions. This information is then transmitted to the brain for interpretation. Defects in color vision arise from cone-cell pigments that are either lacking or abnormal. Those affected can see the difference between most or many colors and are blind to only a few.

In extremely rare cases, all cone pigments are lacking and the person can see only white, black and shades of gray. However, 99% of those with colorblindness are red-green colorblind. When trying to select a color from a box of 96 crayons, for instance, a person who is red-green colorblind sees only varying intensities of blue and yellow, along with white, gray and black.

Colorblindness is more common in men versus women ‹ about 9% of men and .25% of women ‹ because the genes that determine the ability to distinguish colors are carried on the X chromosome, the sex chromosome that boys inherit from their mothers.

The inability to distinguish colors can cause difficulties in daily life ‹ in education (reading and math), driving (problems with stoplights) and in certain job situations.

Currently, there is no cure for congenital colorblindness; however, there are many products that can help. If you would like to learn more about colorblindness, check out this helpful Web site: http://members.aol.com/nocolorvsn/color.htm.