Color Vision

Friday, October 11th

INFORM: Pacing

Module four is a wonderfully fascinating unit - with lots of great activities for you to do. Remember, however, that the pace of the module is faster than we have been moving - you frequently need to complete more than one assignment a day. Please do not fall behind!

INSTRUCT: Color Vision

Like many of the other differences we find in human beings, there are also differences in our ability to see color. This photo of the Earth shows normal vision.

It is commonly known that some of our population is “color-blind.” Just over 8 percent of all males show color weaknesses, but slightly less than .05 percent of all females show similar deficits. (Color defects are genetically transmitted; recent research has conclusively mapped the pattern of this transmission.)

What is it like to be Color-Blind?

Check out this short video from Kids Health, and then read the information about types of color variance!


Monochromats have either no functioning cones or only one functioning cone type and respond to light in much the same way that a black and white film does. Only a very small percentage of people actually suffer from this form of color blindness.


Dichromats have one malfunctioning cone system.

Deuteranopia, the most common form of dichromacy, is a malfunction in the green cone system. People with this deficiency are able to respond to green light but cannot distinguish green from certain combinations of red and blue.


Tritanopia, an absence or malfunction of the blue cone system, was not discovered until about 1950. The individuals with this disorder, instead of seeing the spectrum as composed of blues and yellows as do other dichromats, see the longer wavelengths as red and the shorter ones as bluish green.

Color Test - Online Color Challenge from X-Rite

Check out this online color vision test - It takes a little time, but It's pretty cool!

Photo Credits

World photos