"Colorblindness" includes all forms of color deficiency. "Daltonism" was first discovered by the English biologist-schoolmaster (Dalton) who determined that he saw things differently. The most common type of color deficiency (red-green) is inherited by men from their Mothers, who do not have it, but might be called carriers. We miss the ability to see 'green'. Other types are inherited differently and miss different colors. One may also lose colorvision by taking certain drugs or getting diseases, such as Alzheimers or diabetes (low blood sugar).
How things look to someone who is colorblind. Overview of tests and genetics.
Aspects of Perception
Illustrates "how people with less than three types of cones can confuse different wavelengths."
Presents symptoms, causes, types, and tests. Includes a form for questioning an optometrist.
Short facts on condition. Links to self-diagnostic test.
Explains mechanics and physiology, and includes color wheels to simulate what the disabled see.
Colors for the Color Blind
Provides background information and a set of charts to help those working with computer colors.
Wikipedia article includes a simple diagnostic test, rates of incidence, causes, and types of deficiency.
Mayo Clinic: Poor Color Vision
Includes overview, causes, screening, diagnosis, treatment, and coping skills.
Arizona State University provides definitions and tests.
The Upside of Color Blindness
DISCOVER Magazine reports, "Color-blind monkeys make better insect hunters." Includes pictures of what the colorblind (do not) see, and Pseudoisochromatic plate.
Software utility that transforms colors of the computer display into the discriminable colors for people with color blindness.
Genetic Studies Endow Mice with New Color Vision
Howard Hughes Medical Institute researchers give human color vision to mice. (March 23, 2007)