What enables people to see color

Deutan color blindness is a form of red-green color blindness characterized by the shifting of green light-sensitive cone cells closer to red-sensitive cells than is normal. This causes “green-deficient” color blindness.

Protan color blindness is a form of red-green color blindness characterized by the shifting of red light-sensitive cone cells closer to green-sensitive cells than is normal. This causes “red-deficient” color blindness.

Tritan color deficiency is most commonly acquired later in life due to aging of the eye or medical complications. It is characterized by a reduction in the sensitivity of the blue light-sensitive cones such that blue shades seem darker and less vibrant. In extremely rare cases tritanopia can be inherited also.

Achromatopsia is also known as “complete color blindness” and is the only type that fully lives up to the term “color blind”. It is extremely rare, however, those who have achromatopsia only see the world in shades of grey, black and white. In some cases low vision disorders such as progressive cone dystrophy can cause a gradual deterioration of color vision that eventually turns into complete achromatopsia.

Still curious to learn more? Check out our Types of Color Blindness page for a more in-depth look at these and more forms of color blindness and how they affect those who have them.