#colorblindness #accessibility
3-5 min

Color Blindness: Symptoms, Causes & Treatments

Color is an integral part of life. However, not everyone is able to experience it in the same way. 

Color blindness is a visual impairment that affects how someone perceives and distinguishes color, and it’s more common than you might think.

This in-depth guide will unpack everything you need to know about the causes and symptoms associated with color blindness and what you can do to cope if you are diagnosed. 

Infographic: Color Blindess

What Is Color Blindness?

Color blindness generally doesn’t mean someone can’t see color at all. It simply prevents a person from seeing colors in a traditional way. However, in some rare instances, there is a certain type of color blindness that can eliminate the ability to see any color.

Color blindness is usually present at birth and occurs when the nerve cells in the retina of the eye don’t function correctly. Also known as cones, these nerves are responsible for processing light and images and sending signals to the brain, which is what allows you to determine color. 

An optometrist or ophthalmologist is able to diagnose color blindness. This is done with a color plate test. During the test, your doctor will make you look at circles, each of which is made up of different colored dots. Within the circle is a number or shape, which you will be asked to identify. The different color combinations are what will determine whether you are color blind and what type you have. 

If you are diagnosed with color blindness, an optometrist can help you better navigate your day-to-day and determine whether color blindness glasses could be an option. 

How Common is Color Blindness?

Believe it or not, it is far more likely for someone to be color blind than completely blind. While just over 40 million people around the world are blind, there are over 300 million color blind people, with men being affected more often.  In terms of countries, you will find the largest color blind population in India.

If we look at the United States specifically, around 12 million Americans have been diagnosed with color blindness. Roughly 7 percent of all males and 0.4 percent of all females in the USA are color blind. 

Color Blindness Symptoms

So, how can you tell whether you might be color blind?

In most instances, color blindness starts out as confusion. For example, you may think a piece of clothing is a particular color when it isn’t, or a child may have trouble differentiating between different color crayons. 

The most common colors to confuse are red vs. green as well as blue vs. yellow. And then, in rare instances, you can’t differentiate any colors at all. 

Some of the other symptoms that often accompany color blindness include head and eye pain, light sensitivity, and a low attention span. 

Causes of Color Blindness

Research shows that genetics are the main cause of color blindness. The genes that cause faults in the nerves of the retina are usually inherited from parents because they travel in the X chromosome. 

Other causes of color blindness include:

  • Optic nerve damage
  • Physical damage to the eye
  • Exposure to chemicals that damage the eye
  • Cataract
  • Age
  • Damages to the area of the brain that processes color

Understanding the Different Color Blindness Types

Color blindness is directly linked to the cones in your eyes, each of which is responsible for processing different colors. Everyone is born with three types of cones:

  • L cones: These red-sensing cones perceive long wavelengths of around 560 nanometers.
  • M cones: These are green-sensing cones that are responsible for processing mid wavelengths of around 530 nanometers. 
  • S cones: These are blue-sensing cones that perceive short wavelengths of around 420 nanometers. 

Vision categories outline how well these cones are working together.

Trichromacy: All three cones are working as they should, and someone has full-color vision. 

Anomalous trichromacy: Even though all cones are present, there is one that isn’t sensitive enough to light. This impacts someone’s ability to see colors in a traditional way. They generally confuse pale or lighter colors or vivid colors. 

Dichromacy: This indicates one of the cones is missing, which means the eye is only working with two types of wavelengths instead of three. Dichromacy makes it difficult to differentiate between saturated colors. 

Monochromacy: Lastly, monochromacy indicates that only one cone is present or none at all. This means someone is able to see limited colors or no color at all. Surroundings will often appear gray. 

Now that you have a deeper understanding of how the cones inside the eye impact vision let’s get into color blindness types:

Red-Green Color Deficiency

This is the most common type of color blindness. Any colors that have red or green in them will be difficult to perceive. When the L cones are missing, someone won’t be able to see red. Red will often look blue, yellow, gold, or black. 

If the M cones are missing, someone won’t be able to see green. Green will often look blue or gold, and certain shades of red will appear green. Even yellow may appear green in some instances. 

Red-green color deficiencies are far more common in men than women because this type of color blindness travels in the X chromosome. Boys inherit their single X chromosome from their mothers, so if a mother is color blind, her son will be too. Because girls inherit their two X chromosomes from both parents, they would both need to be color blind for their daughter to be.  

Blue-Yellow Color Deficiency

This type of color blindness is a little less common and impacts someone’s ability to perceive blue and yellow. When the S cone is missing, someone isn’t able to see blue light. Blue will appear red, pink, or even lavender. It’s also possible to have all three cones, but have the S cone be less sensitive to blue light. This causes blues to appear green. Yellow will also be difficult to perceive. 

Blue Cone Monochromacy 

When neither the L nor M cones are working correctly, it causes a rare form of color blindness called blue cone monochromacy. People with this variation will mostly see grays. Photophobia, nearsightedness, and nystagmus are often also associated with this type of color blindness. 

Rod Monochromacy 

If all three cones are missing or they simply don’t work, it causes rod monochromacy, also known as achromatopsia. Rod monochromacy means someone sees everything as gray and will most likely have other visual impairments.

Color Blindness Treatment

Unfortunately, there is no way to treat or cure color blindness. All that your healthcare provider can do is treat any underlying conditions and adjust your medication where required. In some instances, medication can be used to slightly improve color blindness but not cure it entirely. 

There is also the option of purchasing color blindness glasses, but only if your condition is mild. These specialized glasses are designed to enhance color contrast, allowing you to decipher color differences more easily. It should also be noted that everyone has a slightly different experience with these glasses, so it’s best to manage your expectations. It also helps to first consult with an eye specialist to determine whether the glasses are a worthwhile purchase. 

Can Color Blindness Be Prevented?

There is no real way to prevent color blindness since it’s generally present at birth in most instances. To prevent color blindness later in life, make a point of scheduling regular eye exams and follow a healthy lifestyle. Limiting your exposure to harmful chemicals and high-impact activities can also help prevent eye damage. 

Living with Color Blindness

Color blindness can create a few challenges in day-to-day life such as picking an outfit, driving, and determining whether food is cooked, but it doesn’t need to limit your life entirely. 

Here are a few tips that can make it a little easier to cope with your color blindness diagnosis:

  • Take note of accessible websites. Accessible websites are color-blind-friendly. They give you the ability to adjust color contrast ratios to suit your needs, ensuring you can still browse, shop, chat, and learn as usual. If you happen to be a website owner, you may find this guide to color blindness web design helpful. 
  • Speak to your employer. If you’ve recently been diagnosed with color blindness, make your employer aware of it. It always helps to have some additional support, especially in spaces where you spend a lot of time. You could also consider changing your career to something that’s more suitable to your diagnosis. 
  • Work on spatial arrangement. When you work on remembering where objects of a certain color belong, you won’t need to worry about their colors. For example, we know that the red traffic light is always at the top. 
  • Download an app. Today, there are a number of apps that you can download that will make it a little easier to decipher between colors. Colorblind Helper and Color Blind Pal are two examples. 
  • Get organized. Organizing and labeling the objects that you use most often throughout your day is another way to move away from relying on color. 
  • Consider investing in color blindness glasses. Depending on the severity of your color blindness, there is the option of investing in color blindness glasses, which can make it a little easier to differentiate color. 
  • Learn new ways to cook and shop for food. Instead of relying on color to determine whether meat is cooked, purchase a meat thermometer. When shopping for fresh produce, get to know what characteristics are associated with fresher foods. For example, fresh asparagus will have tighter buds. 


Color blindness can be a frustrating diagnosis to receive initially, but it’s still possible to continue living a normal and fulfilling life. What’s more, accessibility has become a top priority across the world, which means support and technology is more readily available to people living with this unique visual impairment.


Color blindness is inherited as a recessive trait. It’s linked to the X chromosome, which is why it tends to affect more men than women. This trait is caused by gene mutations that are linked to the photoreceptors. 

Color blindness is typically divided into three different categories, which are linked to the cones in the retina of the eye. We are generally all born with three cones, namely the L, M, and S cones. Each of these cones processes different colors in varying wavelengths.

  1. Anomalous trichromacy: This indicates that all three cones are present, but one of them isn’t sensitive enough to light. Someone with trichromacy will confuse lighter colors or vivid colors. 
  2. Dichromacy: When only two of the three cones in the retina are working, it’s difficult for someone to differentiate between saturated colors. 
  3. Monochromacy: Monochromacy indicates that only one cone is present and, in some instances, none at all. A person with this type of color blindness can see limited colors or none at all. 

While color blindness has several different symptoms, some of the most common are:

  • Difficulty distinguishing between certain colors, green, red, and blue in particular.
  • Light sensitivity.
  • Head or eye aches.

Some children also present with an enhanced sense of smell and night vision, as well as a decreased attention span. 

The ADA defines a disability as any condition that substantially limits a major life activity. There is some debate as to whether color blindness is truly a disability, as it doesn’t limit someone’s ability to function in day-to-day activities in a substantial way. 

When a person has a blue-yellow color deficiency, blue can often appear red, pink, lavender, or green. This is generally linked to an issue with the S cone in the eye. When the S cone is missing or defective, it’s less sensitive to blue light, which is why this color can be hard to perceive or is confused with others. 

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