Color blindness, or color vision deficiency, is when a person cannot distinguish certain colors correctly. Many people mistakenly think that color blindness is seeing the world in black and white, but complete color blindness is rare. Colorblind people often have difficulty distinguishing certain colors, mistaking them for the same color.
In our eyes, there are cells called cones that help us distinguish colors. There are three different types of cones—one that lets us see red, one that lets us see green, and one that lets us see blue. When a person is colorblind, one or more cone cell types are either absent or not working properly, causing them to not see certain colors or see them differently.
Types of Color Blindness
About 8% of men and 0.4% of women have color vision deficits. There are different types of color blindness, some more common than others.
Red-green color blindness
People who are colorblind often have difficulty distinguishing red and green, mistaking them for the same color. This type of color blindness is the most common. The different types of red-green color blindness are:
- Dueteranomaly is the most common type, where green looks more like red.
- Protanomaly is the opposite of deuteranomaly, in which reds look more like greens and are less bright.
- Redblindness is when a person cannot see red.
- Deuteranopia is when one cannot see green.
Red-green colorblindness has trouble distinguishing red from green, while yellow-blue colorblindness has trouble distinguishing blue from green and yellow from red. Occurring in less than 10,000 people worldwide, this type of color blindness is less common and affects men and women equally.
There are two types of yellow-blue blindness:
- Tritanomaly: With tritanomaly, you cannot distinguish between blue and green and yellow and red.
- Triangle Blindness: If you have triangle blindness, you cannot distinguish between blue and green, purple and red, and yellow and pink. Colors also appear less bright to you.
complete color blindness
Totally Colorblind or Totally Colorblind colorblind There are no functional cones, no color can be seen. Occasionally, a person may have incomplete color blindness, in which there are functional cones that only allow them to see certain colors. People with color blindness often have impaired vision, sensitivity to light, and nystagmus.
Color blindness is generally rare, affecting an estimated 1 in 30,000 people worldwide, and complete color blindness is more common than incomplete color blindness.
Color blindness is caused by cells in the retina that mishandle color. Specialized cone cells responsible for color vision lack the ability to send the right signals to the brain.
Color blindness is usually hereditary, which means that the condition is usually passed on from both parents. Sometimes certain diseases affect the eyes or brain and cause color blindness, called “acquired color blindness.” Some of these diseases include:
- macular degeneration
- Alzheimer’s disease
- multiple sclerosis
Some drugs, especially Plaquenil (hydroxychloroquine), can affect cells in the eye, sometimes causing color blindness. Aging can also cause this disease; as the lens darkens with age, older adults may find it difficult to distinguish colors.
The main symptom of color blindness is difficulty distinguishing between red and green or blue and yellow. When children have difficulty learning colors, parents often suspect colorblindness. Children with problems at school should be tested for color blindness, as many learning materials rely heavily on students being able to distinguish colors.
The most common test to diagnose color blindness is the Ishihara test. This quick and easy test consists of a series of pictures consisting of colored dots. There is a figure in the dots, usually a number made up of dots of different colors. People with normal color vision will be able to see numbers, but people with color blindness will see numbers differently or not at all.
Another test used to diagnose color blindness is called an arrangement or hue test, in which the patient is asked to arrange a set of colored chips or blocks in a specific order.
Unfortunately, there is no cure for color blindness. However, people with color vision deficiencies have learned to cope with the disorder. Patients usually teach themselves how to distinguish between different colors and shades of color.
Some doctors will prescribe color correction lenses based on the severity of the color vision deficiency. In addition, there are computer software and phone applications that can help people with color vision disorders.
If you are colorblind, there are many strategies to help you with everyday tasks and identify colors easily. First, you can talk to your doctor about contact lenses or glasses designed for people with color blindness. These types of contact lenses and glasses may help distinguish colors that you have trouble seeing.
There are also smartphone apps that use your phone’s camera to name colors, which can be helpful when shopping for clothes or other items and understanding the colors of your surroundings.
You can also ask people around you about colors you can’t see well, especially the staff at the store you’re visiting.
In the US, it is legal to drive if you are colorblind. Traffic light colors are strategically sequenced to help drivers understand which lights are being displayed. For vertical lights, the red light (stop) is always at the top, the green light (going) is always at the bottom, and the yellow light (slow down) is always in the middle.
For horizontal lights, the red light (stop) is always on the left, the green light (going) is always on the right, and the yellow light (slow down) is always in the middle.
Color blindness is a rare disorder with few restrictions on those affected. By understanding strategies like remembering traffic lights and using tools like color-correcting lenses, people with color blindness are often able to adjust and lead normal lives.