Color Blindness Test

What is a color blindness test?

A color blindness test is a method eye care providers use to check your color vision. Color blindness testing is noninvasive, not painful and usually only takes a few minutes. It happens in eye care providers’ offices during checkups and also in many schools.

If you have color blindness (color vision deficiency), you don’t see colors in the traditional way. There are many types of color blindness. These include red-green (most common), blue-yellow and a few other ones. Also, color blindness can be either inherited (due to genetic mutations) or acquired (due to medical conditions or other reasons). In most people, it’s genetic.

Having color vision deficiency rarely means you see no color at all (a type known as achromatopsia). Instead, it means cells in your eyes called cones are less sensitive to wavelengths or types of light. As a result, you don’t see some colors, or you see some colors differently compared with people who have full color vision. Color blindness ranges from mild to severe. It may cause you no trouble at all, or it may significantly impact your quality of life.

You may have no idea you have color vision deficiency until you take a test. That’s because you’re used to seeing colors in a certain way and have no point of comparison.

There are many tests that check you for color blindness, and they each work slightly differently. You can find many tests online, and those can be a good starting place if you have concerns about your color vision. But to get the most accurate results, it’s important to see an eye care provider. An optometrist or ophthalmologist will give you a comprehensive eye exam that includes testing your color vision. Your provider will also discuss the results with you and help you understand what they mean.

Who needs a color blindness or color vision test?

You may benefit from color vision testing if you:

• Find it hard to tell the difference between colors or shades.
• Feel confused when choosing or talking about colors with others who seem to see colors differently than you.
• Wish to pursue a career that requires full color vision (for example, if you want to become a pilot, a graphic designer or a fashion designer).

If your child seems to have trouble recognizing or using colors, it’s a good idea to take them for an eye exam. While providers recommend that your child’s first eye exam occur before their first birthday if possible, color blindness testing can only be done reliably once your child can follow the provider’s instructions and answer their questions. Usually, this is after age 3 or 4.

Talk to your child’s eye care provider if you have concerns about their ability to see and distinguish colors. Children who have color blindness may have trouble with color-coded materials at school. So, it’s important to test for and diagnose color blindness as early as possible so your child can receive any needed academic support.

What tests are done for color blindness?

Color vision tests fall into several categories, described below. Most of these tests only take a few minutes, but the more complex ones may take up to 20 minutes and are generally reserved for special cases. All of the tests are noninvasive and don’t cause any pain or discomfort. They simply involve looking at printed materials or a computer screen and identifying what you see. There are several kinds of tests.

Color plates test (pseudoisochromatic plates test)

For these tests, you need to distinguish a number or symbol from its background. Small circles or dots make up the image and its background. So, recognizing certain colors or shades is crucial for visually separating the number or symbol from the details behind it.

• Ishihara test. This is the test eye care providers use most often when adults come in for appointments. A provider shows you a set of eight to 38 plates, each with a different number or symbol. You tell the provider what you see. The results can show if you have a type of red-green colorblindness. This test doesn’t show blue-yellow color blindness.
• Richmond Hardy-Rand-Rittler test. More commonly called the Richmond HRR, this test checks for red-green and blue-yellow color vision deficiency. It also shows whether your condition is mild, moderate or severe. You look at 24 plates that each contain one or two symbols (including crosses, circles and triangles). You identify what you see and where it’s located on the plate.
• Cambridge Color Test. This is a computer-based test that checks for red-green and blue-yellow color blindness. You look at different plates that each contain the letter “C.” You identify where the opening of the “C” faces (toward the top, bottom, left or right).
• Color Vision Testing Made Easy (CVTME). This test checks for red-green color blindness in children aged 3 to 6. Your child looks at a series of 12 plates and identifies the images they see on each. The first nine plates contain simple pictures like circles, squares and stars. The last three plates contain more complicated pictures like houses, boats or dogs.
• Neitz Test of Color Vision. This is another testing option that’s suitable for children. It checks for red-green and blue-yellow color vision deficiencies. Your child looks at a series of nine squares. Each square contains a diamond, square, triangle, circle or no symbol. Your child says what they see in each square. To ensure the most accurate results, most children take the test twice in a row.

Ordering test

Ordering tests (called “ordering” because you put objects in a certain order depending on their colors and shades) involve looking at a series of cards, each a different color.

• Farnsworth-Munsell 100-Hue. This test checks for red-green and blue-yellow color blindness. It also shows how well you can tell the difference between colors. You look at 85 cards divided into four groups and put them in order according to their color and shade. This test is particularly helpful for diagnosing acquired color blindness.
• Farnsworth-Munsell D-15. This is a shorter version of the 100-hue test that uses just 15 of the 85 cards. This test may not capture very mild cases of color blindness.
• Lanthony desaturated D-15. This test is similar to the Farnsworth-Munsell D-15 and is helpful as a follow-up. It uses cards with more muted color shades. Plus, the colors have more subtle differences between them.

Comparison test

The main comparison test uses a device called an anomaloscope. Eye care providers consider this the gold standard for diagnosing red-green color blindness. It’s almost exclusively used in research projects that investigate color vision. It reveals the specific type of red-green color deficiency you have and also how severe it is.

For this test, you look into a device that looks a bit like a microscope. You see a circle that’s divided into a top half and a bottom half. Each half is a different color. The top color stays the same while you use knobs to adjust the bottom color to match it. You continue this process with a series of circles. People with red-green color blindness will see some colors as very similar when in fact they’re not.

How do I prepare?

There’s nothing you need to prepare before a color vision test. However, it’s helpful to tell your provider about:

• Any difficulties you’re having with colors.
• Anyone in your biological family who has color blindness.

What can I expect after a color blindness test?

Color blindness testing is quick. When your test is over, your provider will talk with you about the results. You may need additional tests to get a more accurate diagnosis.

There’s no medical treatment for color blindness, and it can’t be cured. However, some people find that color-blindness glasses help them better see the contrast between colors. Plus, you can learn tips and tricks for identifying colors in your daily life. These include using labels for your clothes or downloading apps that help you navigate shopping.

What are the risks of this test?

Color vision tests are safe and have no risks.

What type of results do you get and what do the results mean?

Each test produces slightly different results. Your eye care provider will tell you the results and explain what they mean. In general, color blindness tests show:

• Whether or not you have color vision deficiency (color blindness).
• What type of color blindness you have.
• How severe your condition is.

Not every test shows all of this information. That’s why you may need more than one test to diagnose your specific form of color blindness.

When should I call my doctor?

Call your eye care provider if you:

• Have trouble telling the difference between colors or shades.
• Have blurred vision or other problems with your sight.
• Have questions or concerns about your child’s vision.

How do I know if I’m color blind?

You might have color blindness if you can’t tell the difference between certain shades or colors that others point out to you. These could be colors of clothes, decorations or even foods. For example, you might think meat is fully cooked when, in fact, it’s rare. Ripe, red tomatoes might look the same to you as green tomatoes. Children who have color vision deficiencies may refuse to eat certain green foods because they look brown or unappealing.

You might live many years without knowing you have color blindness. This can happen when you have a mild form of the condition or don’t talk about the colors you see with others. A color blindness test can show whether you have color vision deficiency and help identify the specific type. Talk to your eye care provider if you suspect you don’t see colors in the traditional way.

A note from Cleveland Clinic

Color blindness tests can show whether you see colors differently than people with full-color vision. Such tests can also identify the specific type of color blindness you have.

For most people, color blindness is a minor nuisance that doesn’t interfere much with daily life. However, some adults with more severe forms may struggle with workplace tasks. Plus, children who aren’t diagnosed may have trouble with assignments that require seeing the full spectrum of colors. Color blindness testing can help get to the root of the problem and put you on a path toward solutions.