What Is Color Vision?

About one out of 12 people lack the ability to see all colors.

Color vision refers to your eyes' ability to see colors, particularly the colors of red, yellow and green. When light hits the cones, or color-sensitive cells, in the back of your eye, chemicals send color information to your brain, which distinguishes hundreds of colors from each other.

Lack of Color Vision

Poor color vision, or colorblindness, occurs when the cones in the eye lack the chemicals needed to distinguish certain colors. Most colorblindness is inherited, with men much more likely to be colorblind than women. The most common kind of poor color vision is a deficiency in the ability to see green and red. In addition, some diseases, medications, and chemical exposure can limit the ability to see color well.

Tests for Color Vision

Most tests for color vision ask the person being tested to distinguish a number from within a multi-colored pattern of dots; a person with poor color vision is unlikely to see any number at all. Similar tests for young children ask them to distinguish shapes rather than numbers.

What Things Look Like to the Colorblind

People with poor color vision can see colors other than those for which they are colorblind; a person with red/green colorblindness has no trouble seeing shades of blue or yellow, for instance. Shades of colors change for the colorblind as well, so that someone with red/green colorblindness will see purple as blue, with the red hues removed. Blue/yellow colorblindness does exist, as does total colorblindness, but both are extremely rare.

References

• Mayo Clinic: Poor Color Vision
• Color Vision Testing: What Color Deficient People See
• Vischeck: Color Vision Simulator Examples
• Toledo Bend: What Color Vision Deficiency Is