The naturalist, chemist and mathematician of English origin John dalton (1766 -1844 ) was one of the main responsible for the study of the achromatopsia , a disease of a genetic nature and congenital profile that, according to experts, is not progressive. It is an anomaly that affects the view . For the valuable contributions of this specialist, over time the partial achromatopsia began to describe how colour blindness .

Color blindness is framed in the dyschromatopsia , a term that refers to an inconvenience based on the inability to differentiate colors . Although not all colorblind people confuse the same shades, most often they have difficulty distinguishing between green and red. Instead, a colorblind may appreciate more shades of violet than a subject with normal vision
When we talk about this genetic problem we have to state that there are several types of it. Specifically at a general level we can determine that there are three:
Monochromatic The person who suffers from this kind of color blindness is characterized in that in the retina he only has a sensitive cone so he only sees one color.
Dichromatic. Two cones of the aforementioned are those of the citizen who suffers from this problem. This fact entails that we find in turn three types of colorblind: protanopes that are absolutely insensitive to red; the deuteranopes that are the ones that confuse the red, green and yellow shadows; and tritanopes that are insensitive to blue while confusing blue and green shadows.
Abnormal trichrometric One of the most frequent cases is this in which the people who suffer from it encounter the fact that they fail to distinguish colors, confuse one another.
In addition to these three kinds of color blindness, we cannot ignore the fact that there is also another one that is called Chromatic. This is a visual defect that occurs very infrequently but is characterized by the fact that whoever suffers it sees everything in black and white and in the corresponding gray range.
There are several methods that exist to determine that someone suffers from color blindness. However, the most frequent procedure is to make use of the so-called Ishihara letters in which numbers in different colors are represented.
Color blindness disorder is linked to a recessive allele associated with X chromosome . In the case of men, inheriting a single X chromosome with the deficiency already becomes colorblind. Women, meanwhile, need a pair of X chromosomes with the deficiency to be diagnosed as colorblind; otherwise, they will only be carriers (so they can transmit color blindness to their children). This difference translates into a broad predominance of the male sex among those who suffer color blindness.
Color blindness implies a flaw in the sensory cells of the retina that react to colors and are known as cones . These are responsible for processing the light that reflect the objects and determine the colors. There is one type of cone that is sensitive to red light, another type of cone that is sensitive to green light and a third type of cone that is sensitive to blue light. The problem of colorblindness arises from the failure of the genes that must produce the pigments of these cones.