Color Blindness: Causes, Types And Treatment
Color blindness is a vision disorder that makes it difficult, even impossible, to distinguish colors. The severity level is very variable; they range from the difficulty in distinguishing some shades of red, green, yellow or blue to the inability to recognize any color.
This disorder is the consequence of an anomaly in the photoreceptors of the eye, called rods and cones. These cells interact with each other and are connected to the brain centers via the optic nerve. We talk about color blindness when the cells are unable to reproduce the image of the pigments.
What are the causes of color blindness?
The perception of color depends on the retina, in which the cones and rods are located. The latter capture white, black and the whole range of grays. Cones, on the other hand, are sensitive to red, blue and green. By collaborating with each other, they make it possible to perceive the different colors and their respective shades.
Color blindness occurs when either rods or cones or both have an abnormality or are not present. These conditions are attributable to genetic causes, the effect of some drugs or a pathology. Let’s find out more.
Genetics
Most cases of color blindness have a genetic origin. The problem is usually passed on from mother to child and does not cause any vision impairment. Although women carry the faulty chromosome that causes the disease, men are more likely to get it.
Medicines
There are several drugs that can alter the perception of colors. Some antipsychotics, such as chlorpromazine and thioridazine, are sometimes responsible for color blindness.
Ethambutol, given to treat tuberculosis, can also alter color perception. These side effects should be evaluated by the doctor who prescribed the drugs in question.
Pathologies
Various eye conditions can cause color blindness. For example, in some cases, glaucoma damages the optic nerve by reducing the ability to distinguish colors or shades. On the other hand, maculopathy or diabetic retinopathy deteriorates the retina and causes the same effect.
In case of cataracts, color perception is not lost, but the latter can be significantly reduced. Other conditions, such as diabetes, multiple sclerosis, Alzheimer’s or Parkinson’s, may also cause color blindness.
Other factors
It has been observed that aging may be responsible for a deficit in color perception in some people. In addition, exposure to toxic chemicals such as styrene, present in some plastics, is associated with this vision disorder.
Types of color blindness
A first classification of different types of color blindness can be drawn up on the basis of the responsible causes. In this case, it is distinguished in inherited and acquired color blindness. The first is transmitted from mother to child, the second is the result of other factors.
Color blindness can also be classified according to the type of dysfunction in color perception. We therefore speak of anomalous trichrome, achromatopsia, monochromacy and dichromacy. Let’s analyze each of them.
Abnormal tri-color
The subject affected by this anomaly has cones inside the retina, but they do not allow him to distinguish colors. It is the most common form of color blindness and can manifest itself in three ways:
- Protanomaly : difficulty in perceiving red light.
- Deuteranomalia: errors in the perception of green light.
- Tritanomalia: difficulty in perceiving blue light.
Achromatopsia: color blindness in black and white
The person sees only in black and white, including shades of gray, because they have no cones inside the retina or as a result of neurological damage. This is a very rare condition, with an incidence of 1 in 100,000 people.
Monochrome
Monochrome takes the name of total color blindness or extreme color blindness. The view is black and white with a wide range of grays. The cones lack two of the three pigments that must be present in these cells. It affects a limited number of people.
Dichromacy, a form of color blindness
It is a form of color blindness that is considered moderately severe and as a result of which there is an absolute lack of perception of one of the three types of light. As in the case of anomalous tri-color, there are three types.
Protanopia
In this case there is a total absence of retinal red photoreceptors. This causes poor color perception at very long band wavelengths. Affected people only perceive these shades as being beige or gray. This is the most common form of dichromacy.
Deuteranopia
In this case, the green retinal photoreceptors are absent. The subject has difficulty perceiving colors with a wavelength at medium bay. This is a severe form of deuteranomaly.
Tritanopia
It is the rarest form of color blindness characterized by the total absence of photoreceptors for the perception of blue color. A difficulty arises associated with the perception of short-band wavelength colors. At the same time, yellow is perceived as being pink.
Treatments and options to improve the life of the color blind person
Today, we have no therapies for the treatment of hereditary color blindness. If the disease was caused by taking certain drugs, by other diseases or by exposure to toxic products, the triggering cause should be addressed.
Lenses with color filters or special contact lenses can help distinguish colors better, but they don’t solve the problem. The research hopes to develop gene replacement techniques that could definitively solve the problem.
People with color blindness can use some techniques and tools to overcome the limitations imposed by the disease. For example, they could memorize the color order of the traffic light, so that they can interpret the signals to know whether to stop or continue.
It may be useful to put a sign on objects that indicates a certain color in order to recognize the shade in question because it is combined with others. Today there are some electronic devices that help distinguish colors.
