Superhuman vision : What is Tetrachromacy ?
Tetrachromacy is a condition that is more common than we previously thought. In fact, almost 12% of women have it. Find out more here !
Tetrachromacy is a condition that interests many scientists. It is a term that refers to visual quality; this means that people or animals with it have a greatly increased visual index.
In fact, they can see up to 100 million colors. Tetrachromacy is found in some animals, such as some birds, fish, insects, and amphibians. In fact, some people can have it too!
How do we see colors ?
Before explaining what tetrachromacy consists of, it’s important to have some basic ideas about how the visual process happens. The retina is a light-sensitive tissue at the back of the eyeball.
It consists of different cells with rods and cones. These are photosensitive cells. Cones allow us to see colors; this is called chromatic vision.
There are different types of cones depending on how they respond to light. Most of the human population has three types of these cones. Each responds to light with a different bandwidth. Then the information goes to the cerebral cortex via the optic nerve.
Therefore, most people have trichromatic vision. One type of cone detects red light, another type of blue light, and a third type of green light. In this way, you can see about 1 million colors.
However, something different happens with some animal species. For example, some fish actually have a fourth type of cone that allows them to perceive variations for each of the colors.
What is tetrachromacy ?
Tetrachromacy is a visual condition that allows you to capture about a hundred times more color than normal. It is estimated that almost 12% of all women in the world have this trait.
These people have a fourth type of cone. These people are called tetrachromats. This fourth cone allows them to achieve a four-dimensional sensory color space. That is, they have a much wider visible spectrum because they can combine more primary colors.
On the other hand, the rest of the people can only combine with three colors – red, green and blue. These are called trichromats. This means that they cannot see all possible variants.
How is it different from other categories ?
We currently know of different types of vision depending on the cones in the retina. The first is trichromatism. In fact, this is the most common way of seeing in humans.
However, vision can also be dichromatic. It is the most common species in animals such as dogs. They are sensitive only to blue and green cones.
Finally, there is tetrachromacy. Specifically, it is difficult to distinguish whether a person has trichromatism or tetrachromacy. Sometimes you can only tell by a biopsy of the retinal tissue.
What causes tetrachromacy ?
Apparently, this condition is almost exclusively for females. This is because it is a variation of the X chromosome where the dichromatic gene is located.
The genes responsible for expressing the red and green cones are on this chromosome. Therefore, females have more tetrachromacy because females have two X chromosomes while males only have 1.
That way, they are more likely to have two different versions of these genes. Thus, they can have four types of cones. But that doesn’t mean that men with tetrachromacy can’t.
How can it be defined ?
Until now, there is no test that can safely diagnose tetrachromacy. Online tests that attempt to confirm this have not been scientifically proven to work.
This is because these tests are performed on digital displays based on RBG technologies. In other words, they are performed with a trichromatic color representation system. However, scientists are trying to make the right tools to diagnose it.
On the other hand, there is a way to definitively diagnose tetrachromacy, but it is complex. To do this, you need to take a retinal sample. This type of biopsies is very difficult to perform because it involves many risks in terms of the patient’s vision.
Tetrachromacy is more common than you think
Tetrachromacy is a visual condition especially seen in some women. The eyes of these people contain another type of cone, which is the retinal cells responsible for color perception. Normally there are three different types, but these people have four types.
As a result, they can see almost a hundred times more color than normal. However, as of today, there is no established method for diagnosing the condition.