Do you know what are the various types of color blindness? This article will give you all the information about color blindness and its various types.
The term color blindness is used to describe an eye problem wherein the person has difficulty in telling some of the colors apart. This problem might either be genetic or it might be due to some minor damages in the eye, brain or the nerves. This is a mild disability and only a small percentage of the population suffers from it. It is said that women are usually the carriers while it’s the male who suffer more from it. Well, females too can suffer from this problem although it is rarer in women.
Definition and Causes of Color Blindness
In the year 1798, an English chemist, John Dalton, published a scientific paper on this matter for the first time. Dalton himself was color blind and that is why this disease is also sometimes known as ‘Daltonism’. In simple terms, color blindness is the color deficiency, where a person cannot see some colors. People who have this problem, face certain difficulties in their daily lives; they have problems in following the traffic signals, since green and red are the important colors that they cannot see, they face problems at home or at workplace etc. People who suffer from this problem should avoid driving, as it can be risky for them as well as for others. Let us now see the various causes of color blindness.
I am sure you have learned about the retina of our eyes. This retina contains around 120 million rods and cones, which help us to see. These rods and cones are called photoreceptors, and their main task is to pass light to our brains. The rods however are not responsible for color vision. The cones are the ones that help us to see the various colors around us. These cones are of three types; one which helps us to see the blue color or the short wavelength, the second one is sensitive to the medium wavelength or green color while the third type is responsible for the long wavelength or red color. Any deficiency in the cones, leads to color blindness.
For example, if there is deficiency in the cones sensitive to red color, then the person will not be able to differentiate the color red. Color blindness is usually hereditary or it may also occur if, due to some eye infection, the retina gets damaged. Here are some other reasons why people suffer from this condition.
- Certain drugs like chloroquine
- Exposure to certain harmful chemicals
- Alzheimer’s disease
- Parkinson disease
- Multiple sclerosis
If you want to test whether or not you are color blind, there are several tests that you can undergo.
There are mainly two groups of color blindness, depending upon the causes or the source. The two groups are:
In this case, the person becomes color blind because the cataracts are infected or damaged or the retina or the optic nerves are affected due to a disease or an infection.
In this case, the person (mostly men) suffers from color blindness due to hereditary reasons. If a male gets the infected X chromosomes, then there are chances that he will suffer from inherited color blindness. If a female on the other hand acquires the X chromosome, then the other X chromosome will dominate over the infected one, hence making them just carriers. This type is further divided into 3 categories. Let us see what they are.
It is also known as ‘total color blindness’. This occurs when all the three types of cones (which have been discussed earlier), stop functioning properly. The cones are either damaged or absent. For a person suffering from this problem, color and light become the same thing. However, this is a rare case and occurs in about 1 in 30,000 people.
This type of color blindness is not as severe as the previous ones. Here, the person loses his ability to identify one of the three basic colors (red, blue and green). This occurs, if one of the three cones is missing. For e.g. if the cones which are sensitive to blue color are missing, then the person cannot identify the blue color.
Dichromacy also, can be divided into 3 types.
- Deuteranopia: In this case, the person suffers from defect in identifying the green color.
- Protanopia: The person suffers from the absence of the red photoreceptors. Red appears dark in color.
- Tritanopia: Unlike the above two, this is a rare type in which the person has the red and green cones, but not the blue one.
This is the most common of the three types . When alteration of the three important cones takes place in its spectral sensitivity, then this problem occurs. This does not result in loss of color but impairs his ability to see.
Thus, these are the three types of color blindness. Sadly, there is no cure for it. But there are some color blindness treatments, that are advised to patients. With these treatments, one can find marked improvement in his condition.