April 9, 2019
Did you know that you can go through life never knowing that you are color blind? It is only when you take a color blind test, or when you are first learning your colors as a child that color deficiencies are even detected. The most common form of color blindness is red-green color blindness. One form of this is deutan color blindness. It is divided into two types: deuteranopia and deuteranomaly.
What does the human eye see when it has deutan vision? It is when you can’t discern red or green colors very well.
Our eyes contain three types of special cells called cones that contain photopigments (known as opsins) that allow us to see in color. These cones are located in the back of the eye. Most of them are found in a place called the fovea. This is located in the center of the macula.
There are three types cones: red, green and blue. With normal color vision, you use all three types of light cones correctly.
If you have deuteranopia, you don’t have working green cone cells. That is why is it sometimes called green-blind. It means that you have the green cones present in your eye, but only your red and blue cones function.
If you have deuteranopia, you can only distinguish 2 to 3 different hues. Someone with normal color vision can distinguish 7 hues.
If you have deuteranomaly, you have working green cone cells, but they are not working properly. It is sometimes called green-weak.
This is a condition you inherit. Certain genes known as OPN1LW, OPN1MW, and OPN1SW provide instructions for making the three opsin pigments in cones. Genetic changes involving the OPN1LW or OPN1MW gene cause red-green color vision defects.
Fortunately, it is so easy to find out that you are color blind. You can get tested at the eye doctor using Ishihara color plates. However, you don’t need to go to an eye doctor. You can also test your color vision by taking an online color blind test like this one. The EyeQue Insight offers a color vision test in addition to other tests like contrast sensitivity and visual acuity from your smartphone. Learn more about the other types of color blindness here.