Color blindness is when you don’t see colors in the traditional way because some cones (nerve cells) in your eyes are missing or don’t work correctly. You may have trouble seeing the difference between certain colors or shades, or perceiving the brightness of colors. Color blindness is usually inherited through a genetic mutation.
Color blindness (color vision deficiency) is a fairly common condition in which you don’t see colors in the traditional way. This happens when cones (a type of nerve cell in your eye retina) aren’t working correctly. Cones process light and images as they enter your eye and send signals to your brain that allow you to perceive color.
Color blindness usually doesn’t mean you can’t see any colors. The vast majority of people with color blindness see a range of colors, but they see some colors differently than others do. They may also have trouble telling the difference between certain colors or shades. Some very rare forms of color blindness make a person unable to see any colors.
For most people, color blindness is inherited. That means it’s passed down from your biological parents — from the mother or birthing parent in the most common red-green forms of color blindness. But you can also acquire color vision deficiency later in life due to medical conditions or other reasons.
If you or your child has color blindness, it’s important to learn the type and severity. Talk to an eye care provider (optometrist or ophthalmologist) about the nature of the condition and how it may affect you.
There are several types of color blindness, defined according to which types of cones aren’t working well. To understand the types of color blindness, it helps to know a bit about cones.
Cones are nerve cells in your eye that detect colors in the visible spectrum of light. This spectrum includes all the wavelengths that humans can see. These range in length from 380 nanometers (short), or nm, to 700 nanometers (long). Normally, you’re born with three types of cones:
Most people have all three types of cones, and these work as they should. However, if you have color vision deficiency, at least one type of cone isn’t working properly. Problems with your cones affect your ability to see colors in the traditional way. General categories that describe how many types of cones you have, and how well they’re working, include:
Within these general categories, there are many specific types of color blindness.
Red-green color deficiency is the most common type of color blindness. It affects how you see any colors or shades that have some red or green in them. There are four main subtypes:
Protanopia and deuteranopia are examples of dichromacy. Protanomaly and deuteranomaly are examples of anomalous trichromacy.
Other terms you might hear are “protan” and “deutan.” Protan and deutan are shorthand ways to talk about red-green colorblindness. Deutan refers to green (you have impaired or missing green-sensing cones, or M cones). Protan refers to red (you have impaired or missing red-sensing cones, or L cones).
Red-green color blindness is much more common among men and people assigned male at birth (AMAB) compared to women and people assigned female at birth (AFAB). This is because the genes for the color vision cone light-sensitive proteins are on the X chromosome, of which males have one and females have two. So if the one X in a male contains abnormal genes, the color blindness will reveal itself, while females can compensate with the other normal gene on the second X chromosome.
Blue-yellow color vision defects (tritan defects) are much less common and include:
Blue-yellow color blindness equally affects people AMAB and people AFAB.
This is the rarest form of color blindness. With this type, you don’t have working L cones or M cones. You only have S cones. It’s hard to tell the difference between colors, and you see mostly grays. You may also have other eye problems, including sensitivity to light (photophobia), nystagmus and nearsightedness.
Achromatopsia is when all or most of your cones are missing or don’t work properly. You see everything in shades of gray. You also have other vision issues that may greatly impact your quality of life.
Inherited color blindness mostly affects men and people assigned male at birth (AMAB). This is due to its genetic inheritance pattern (X-linked recessive). Conditions passed down in this manner are much more common among people AMAB.
People can also acquire color blindness due to certain medical conditions, medications or environmental exposures.
Among people of Northern European ancestry, red-green color blindness affects about 1 in 12 people AMAB and 1 in 200 people AFAB. These numbers vary by ethnicity. Some research shows that Europeans have the highest prevalence of color blindness.
Here are some statistics about the less common forms of color blindness:
Overall, around 300 million people around the world have some form of color blindness (mostly red-green).
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Color blindness can be either inherited (you’re born with it) or acquired (you develop it later in life). The causes are different in each case.
A change (mutation) to your genes causes inherited color blindness.
The most common form, red-green color blindness, follows an X-linked recessive inheritance pattern. Conditions inherited in this way usually affect babies AMAB and are rare among babies AFAB. Here’s a breakdown of the genetics for red-green color blindness.
A male baby:
A female baby:
Acquired color blindness, which usually develops as blue-yellow color deficiency, has many possible causes. These include:
Acquired color blindness is less common than inherited forms.
You might have a form of color blindness if you have trouble:
But to recognize these symptoms, you need to know to look for them. Many people with color blindness don’t know to look for these differences because they’ve always seen colors in the same way. So, they don’t realize anything’s different about their color vision.
That’s why it’s important for children to have a comprehensive eye exam that includes colorblind testing before starting school. Many tests and other classroom materials rely on color to convey information or measure students’ learning. Children who see colors differently may struggle with these materials.
Eye care providers diagnose color blindness using several different tests.
The Ishihara test is the most common test eye care providers use to diagnose red-green color blindness. For this test, a provider shows you a series of color plates. Each plate contains a pattern of small dots. Among those dots, there’s a number (or shape for young children). You identify what you can see on each plate. Some plates include numbers that you can only see with full-color vision. Others include numbers that you can only see with color vision deficiency.
Based on the results of the Ishihara test, your provider may recommend further testing to confirm a diagnosis and learn more.
If you believe you or your child may have color blindness, contact an eye care provider to schedule an eye exam. Be sure to mention your concerns at your appointment.
Color vision deficiency testing is generally appropriate for children ages 4 and older. By age 4, most children can answer questions about what they see. However, your child should have their first comprehensive eye exam much sooner (before their 1st birthday).
Currently, there’s no medical treatment or cure for people with inherited color blindness. If you have acquired color blindness, your healthcare provider will treat the underlying condition or adjust your medications as needed. This may help improve your color vision.
You may have heard of color-blindness glasses. Such glasses may provide a richer color experience for people with mild forms of anomalous trichromacy. The glasses enhance the contrast between colors so people with color vision deficiency can see the differences more clearly. But they don’t allow you to see any new colors, and the results vary based on the individual. Plus, it’s important to know that these glasses aren’t a cure and won’t correct any issues with your cones.
If you’re considering color-blindness glasses, talk to an eye care provider first to learn if they’ll make a difference.
You can’t prevent inherited color blindness. However, you may be able to lower your risk of acquired color blindness. Visit a healthcare provider for yearly checkups and ask about your risk for developing color vision deficiency. Some questions to ask include:
Color blindness might not affect your life much, especially if your condition is mild. More severe forms may interfere with your job, education or personal life. It’s important to talk to your eye care provider about your condition and what you can expect going forward. If your child has color blindness, ask what you can do to help them with school.
Certain careers may be too challenging or unsafe to pursue with color deficiency. These include careers as an electrician, pilot, fashion designer or graphic artist. But you can encourage your child to pursue other careers where color vision won’t play a major role. Talk to counselors or mentors at your child’s school to access resources on career options.
Connect with others who have color vision deficiency or parents of children with the condition. They can share advice and resources for living with color vision deficiency from day to day. Some tips include:
For your eye health and overall health, it’s important to:
Your providers will tell you if you need to come in more often for follow-up appointments or additional testing.
A note from Cleveland Clinic
Color blindness is a common condition that ranges from mild to severe. A mild form may impact your life very little, or not at all. But if color blindness interferes with your ability to pursue your goals, you may feel upset or disappointed.
It may help to know you’re not alone, and that millions of people see color differently than the traditional way. It may also help to connect with others who have the condition and learn from their experiences. Online communities for people with color blindness can help you find resources and support.
If your child has color blindness, talk to their eye care provider about adjustments that may help them in school. It’s also important to talk to your child’s teachers about your child’s condition and how best to support their learning.
Last reviewed by a Cleveland Clinic medical professional on 03/17/2023.
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