Color blindness is the inability of one to distinguish colors, i.e. to make difference between some colors which is normal for many people. Colors play a significant role in a human life. So by not being able to perceive all the colors people suffering from color blindness are deprived from pleasure of enjoying in different scenery. However, this disorder is also harmful in a way that it may cause some difficult and life-threatening situations. For instance, people suffering from color blindness may have frequent car accidents. Some of them, if the condition is severe enough, must not even drive.
The Eye Structure
The human eye is equipped with the organ called retina. This is a light sensitive organ made of two types of cells, rods and cones. As for cone cells, there are three type of these cells. They differ according to a pigment they contain. So each type of cone cells allows us to perceive red, green or blue color. Perceiving different colors is obtained by different extent of stimulation of different types of cones. The presence of these three types of cones makes humans trichromats.
What Causes Color Blindness?
In majority of cases, color blindness is genetic. It is also possible for the condition to become acquired due to some damage to the eye, brain or the optic nerve.
Scientists have shown that damage to chromosomes 19 and several more genes located on X chromosome is responsible for congenital color blindness. Damage to genes on X chromosome makes the condition more frequent among men, because unlike women, they have only one X chromosome.
Color blindness can be of the same intensity or even progress. In such case an individual eventually ends up completely blind.
Types of Color Blindness
Types of color blindness are classified according to damage to different types of cone cells. An individual is normally capable of making difference between three colors, red, blue and yellow. However, in people suffering from color blindness one cannot perceive such difference. The affected person most commonly cannot differentiate blue from yellow. In extreme cases one is so affected that he/she can only differentiate white and black color and their shades without ability to recognize any other color.
Rod monochromacy is a condition characterized by absence of cone cells in the retina. People with this anatomical abnormality have difficulty seeing during normal light intensities.
Cone monochromacy is a condition in which a person has only one kind of cone cells. This person is a cone monochromat and he/she simply cannot distinguish hues.
Protanopia is a problem related to lack of retinal cones, the ones that detect wavelengths. These people are not capable of making difference between colors and hues in the green-yellow-red section. For instance, pink color for these people may appear blue.
Deuteranopia leads to diminished brightness when observing objects due to deficiency of the medium wavelength sensitive cone cells.
Finally, tritanopia is a type of color blindness in which an individual cannot differentiate colors in the blue-yellow section.