Color blindness, also known as color vision deficiency (CVD), is when an individual cannot see colors in the normal way. This happens when the individual cannot distinguish colors like red, green, and yellow like the rest of us. This condition is usually something you have from birth but, sometimes, it may be acquired later in life.
Color blindness affects approximately 1 in 12 men and 1 in 200 women in the world.1 Most color blind individuals can see everything clearly, except for the colors. To know why this happens, let’s take a look at how we see colors first.
How We See The Spectrum Of Colors
The retina of the eye has two types of light-sensitive cells: rods and cones. Rods help you see things clearly at night, which means it supports night vision whereas, cones work in daylight and helps distinguish colors.
There are three types of cone
For instance, if you look at an apple, the reason why you see it red is because your red cone cells are stimulated and send the signal to the brain that interprets it as red. Similarly, if you see a bowl of green grapes, the light entering your eye stimulates both the yellow and blue cone cells, sending signals to the brain which later interprets it as green.
So, an individual who is color blind sees the colors the way they do either because of faulty cones or because your brain hasn’t received the right signals.
It is important to know the signs and
Symptoms Of Color Blindness
Symptoms of color blindness range from mild to severe. Most color blind individuals have mild symptoms. If a child is color blind, it can only be noticed when he or she begins to learn colors. The symptoms include:2
- Trouble seeing colors and the brightness of colors the normal way
- Unable to tell the difference between colors, especially red and green or blue and yellow
As mentioned earlier, color blindness can either be inherited or acquired.
Types Of Color Blindness
1. Inherited Color Blindness
The red, green, and blue cones present in the eyes are known as protan, deutran, and tritan, respectively. The individuals with normal color vision – having all three cones functioning properly – are called
When one of the cones is not able to function normally, the vision is called anomalous trichromacy. This can be divided into three types. In all these three types of trichromacy, the cones function abnormally.
- Protanomaly: The reduced sensitivity to red light
- Deuteranomaly: The reduced sensitivity to green light
- Tritanomaly: The reduced sensitivity to blue light
Protanomaly and deuteranomaly are generally termed as red-green color blindness and this is the most common form of color blindness. Sometimes, there are chances that one of the three cones don’t function at all. This condition can also be divided into three categories, depending on the cone.
- Protanopia: There are no working red cone cells.
- Deuteranopia: There are no working green cone cells.
- Tritanopia: There are no working blue cone cells.
There are some individuals who suffer from severe color blindness. In this condition, they cannot see any color. Their world exists in shades of gray. This condition is called monochromacy.
Let’s examine the different ways an individual can acquire color vision defects.
2. Acquired Color Vision Defects
The acquired color vision defects can be caused due to
- Chronic illnesses: Some medical illnesses can cause color blindness. These illnesses include Alzheimer’s disease, diabetes mellitus, glaucoma, leukemia, liver disease, chronic alcoholism, macular degeneration, multiple sclerosis, Parkinson’s disease, sickle cell anemia, and retinitis pigmentosa.
- Accidents: Certain high-impact accidents that damage parts of the brain or eye can cause color blindness.
- Medications: Certain antibiotics, barbiturates, anti-tuberculosis drugs, high blood pressure medications may cause color blindness.
- Exposure to chemicals: Exposure to industrial or environmental chemicals such as carbon monoxide, carbon disulphide, and those containing lead may result in color blindness.
- Age: Sometimes, one may suffer from color blindness due to physical changes caused by aging. This is most commonly seen in those who are over 60 years old.
The symptoms of acquired color vision defects may vary. Sometimes the symptoms can get better and the condition may be completely reversed, whereas other times they can get worse and progress into more serious problems.
Treatment For Color Blindness
Unfortunately, there is
On the other hand, acquired color vision defects may be reversed depending on the severity of the condition. If the cause is determined and treated, it may be possible to get the normal vision back.
Living with color blindness can be tough. If children are color blind, keep the school authorities informed about the condition. It is important to visit the doctor to know how things can be differently to help cope with the difficulties. Most individuals who suffer from inherited color blindness adapt to it over time.