Colors are not perceived equally by everyone. Daltonists are all those who have problems with color perception, and we differentiate several types of daltonism. The most commonly stated is the inability to distinguish between red and green color, especially in the male populations. In a large number of cases it is hereditary, and occurs in 7% of men and 1% of women. Why more in men than in women? The reason lies in heredity, and the gene responsible for such a situation is located on chromosome X. It is a recessive gene. People with a lack of color perception that are complementary to red and green may have problems with the perception of other colors. It is not right to think that these people do not any color.They just perceive color in a different way. There are also people who do not have color sensitivity at all. In this case, it takes a lot more time to differentiate colors, which is not surprising given the narrowed vision perception that facilitates recognition. Difficulty in differentiating colors, especially red and green, is hereditary. Rare disorders in the yellow-blue spectrum of colors can also be detected by an anomaloscope examination.