​Color Blindness and Its Types

The three types of cones which are present in our eyes are used for distinguishing colors. Cones send color messages to the brain which then identifies the various colors. Not all can experience this. Some people have faulty cones either one faulty cone or two faulty cones. This results in different degrees of color blindness. If there is only one faulty cone then the color perception is decreased to some extent. Whereas, if there are two faulty cones then the color perception defect is more. Thus the degree of vision problem varies accordingly. Men are much affected by color blindness than women. The people affected by color blindness might not be aware of their defect.

People with normal vision are called as Trichromacy. Here, the word ‘tri’ –refers to all three types of cones that correctly allow people to see all the colors. When there is one faulty cone, then that condition is called as dichromat. The word ‘chrome’ refers to color. Men are most among the colorblind people the genes involved in supplying color vision that lie on the X chromosome is only one in men. The common color that is affected in colorblindness is known as red-green color. Hence this is usually termed as red-green color blindness. This is due to the limited sensitivity to red light due to the cone that is missing or the L- cones that are defective. Such condition is called as Protanopia or protanomaly respectively. A deprivation in the sensitivity to green light is caused due to the missing or defective M-waves. This situation is called as Deuteranopia or deuteranomaly respectively. Patients with this kind of color blindness find it difficult to differentiate color variations like reds, greens and oranges. It also cause affectations to differentiate blues and yellows. When the S-cones are absent or weakened, the condition is known as Tritanopia or Tritanomaly respectively. This condition is very rare among people throughout the world. It makes it difficult for the patients to recognize the alteration between some blue colors from greens and some yellow colors from violet.

In some people, their vision only sees black and white color. This condition is termed as monochromacy or achromatopsia. It is caused by the non-functioning of the retinal cones or the absence of the retinal cones. This condition is also rare among the worldly population.

Color blindness is a hereditary factor. This is gained through acquired color vision defect which is due to some chronic illnesses or chemicals or any accident or medications. Color blindness can rarely be cured. Researchers have tested gene therapy with monkeys for its effectiveness. But consulting a doctor is always advisable in this disease too. Ishihara Plate test comes for help.