A color vision test, also known as the Ishihara color test, measures your ability to tell the difference among colors. If you don’t pass this test, you may have poor color vision, or your doctor may ...

Squirrel monkeys, which are naturally red-green color-blind, can attain humanlike color vision when injected with the gene for a human photoreceptor. The research, performed in adult animals, suggests ...

Many genetic mutations in visual pigments, spread over millions of years, were required for humans to evolve from a primitive mammal with a dim, shadowy view of the world into a greater ape able to ...