How to use the color vision test
- Set your screen brightness to medium or higher and turn off anything that changes colors, such as night mode or a blue-light filter.
- Press “Start the test” and the dot pictures appear one at a time. Enter the two-digit number you see and press “Submit”. If you cannot see one, press “Can’t see”.
- The first plate is a practice plate that everyone can read. If you cannot read it, your screen may be the cause, so do not trust the result and try again after changing your settings.
- When the 7 plates are done you get the result and a table of your answers. In the simulator below you can upload an image or choose an example to compare side by side how it looks to someone with a color vision deficiency.
What color blindness and color weakness are
The human eye has three kinds of cone cells that sense color, responding to red, green and blue light. If one of them is weak or missing, certain colors become hard to tell apart. A problem with the red-sensitive cones is called protan (type 1), the green-sensitive cones deutan (type 2), and the blue-sensitive cones tritan (type 3). A weakened cone is called color weakness, a missing one color blindness, and total color blindness, where all three are missing, is very rare.
Red-green deficiency is linked to the X chromosome, so it is far more common in men. It is often put at roughly 8% of men and about 0.5% of women, though it varies by population and study. Blue-yellow deficiency is much rarer. Some diseases, medicines and aging can also change color perception later in life.
How this test was made
The dot plates give the dots inside and outside the number shape a color difference only, and randomize the brightness of each dot. People with normal color vision find the number from the color difference, but a person who cannot tell certain colors apart cannot find it from brightness. We worked out the color directions that red-type, green-type and blue-yellow-type deficiencies cannot distinguish using a simulation calculation, and designed the plates along them.
These plates were made for this site and differ from the plates used in clinics, such as the Ishihara test. Their accuracy has not been verified in clinical studies, and colors differ by monitor and settings. This test is only a reference screening and cannot be used for diagnosis.
Reading the simulator and its limits
The simulator shows the original image with its colors converted for each type of color vision. Lowering the severity gives something closer to a mild weakness, which is an approximation made by blending in a straight line between normal and the complete case. What people see differs even within the same type, and the simulation shows only an average appearance. Use it to understand the difficulty of a family member or coworker with a deficiency and to check whether your own designs remain readable.
Designing for people with color vision deficiency
- Do not rely on color alone. Use shapes, patterns and text together. Labeling chart bars directly or using different line styles helps.
- Avoid easily confused pairs such as red and green or green and brown, and make sure there is enough difference in brightness.
- Consider pairs such as blue and orange that stay relatively distinguishable across types of color vision.
- For important information like signals and warnings, communicate it by position, icon or wording as well as color.
When to see an eye doctor
If colors suddenly start to look different, or look wrong in only one eye, it could be an eye disease and you should see an eye doctor. Some schools and jobs require a color vision test, so if you need an accurate result, get a proper test at a clinic, such as pseudoisochromatic plates and a color arrangement test. A proper test can tell the type and degree as well.
Notes
This tool is not a medical diagnosis. Results can vary with screen brightness, color correction, room lighting and tiredness. Results and uploaded images are processed only on your device and are not stored or sent to a server.
Frequently asked questions
How accurate is this test?
These are screening plates made for this site and have not been clinically validated. Results can change with your screen, so treat them as a reference and see an eye doctor for an accurate diagnosis.
Can women have color vision deficiency too?
Yes. It is much rarer than in men, often put at about 0.5%.
Can color vision deficiency be fixed?
Inherited color vision deficiency is not known to be curable into normal color vision. Special lenses that aim to help tell colors apart are sold, but the effect varies a lot from person to person.
Is the image I upload sent to a server?
No. Images are processed only in your browser and are neither sent to a server nor stored.