The unequal crossover in the X-chromosome which causes this disorder is much more easily achieved than the mechanisms which cause other types of color blindness, due to the proximity of the two pigment genes. Five to eight percent of men are affected with this genetic condition, and due to a lacking pigment, have trouble distinguishing between red, green and brown. However, current research on blue-cone monochromats shows that signals from some rods and cones may be traveling by separate pathways to where wavelength discrimination takes place, making color vision possible in this type of monochromat, when both rods and blue cones are working simultaneously under twilight conditions. There is no treatment for this color deficiency, only ways to alleviate its expression. The consequences on the lives of complete achromats are many, and those of children should especially be considered.
Many educational materials use different colors to teach.
They may also not have yet learned to discern the different shades of grey, and may need help deciphering traffic signals. His deficiency made him group colors by their shades of gray or black. He would place red and black blocks together, green and blue blocks together, and have separate piles of white and yellow. A complete achromat has no functional cones at all and sees completely within the scotopic region. A person with normal color vision shows a maximum sensitivity at 530 nm, but for incomplete achromats, there is no wavelength discrimination beyond 520 nm, and near normal discrimination is observed between 440 and 500 nm.