What is color blindness?
Color blindness — more accurately called color vision deficiency — is the reduced ability to distinguish between certain colors. It affects approximately 1 in 12 men and 1 in 200 women worldwide. The most common form is red-green color blindness, where the eye's red or green cone cells are absent or function differently than typical.
Most people with color vision differences are not fully "blind" to color — they simply perceive certain hues differently from the majority. Red may appear brownish, green may look similar to yellow, or the two may appear almost identical. Many people live their entire lives without knowing they have any color vision difference at all.
Color vision differences are almost always genetic and present from birth. They are caused by changes in the cone cells of the retina — the light-sensitive cells responsible for distinguishing color. There are three types of cone cells, each sensitive to different wavelengths of light. When one or more types are missing or altered, color perception changes in predictable ways.
Types of color blindness explained
Red-green color blindness is by far the most common type, affecting roughly 8% of men and 0.5% of women. It comes in two main forms. Deuteranomaly means reduced sensitivity to green wavelengths — greens appear more yellow or brown. Protanomaly means reduced sensitivity to red wavelengths — reds appear darker and less vibrant. Both types make it difficult to distinguish between red and green hues.
Blue-yellow color blindness (tritanomaly) is much rarer, affecting less than 0.01% of the population. People with this type struggle to tell blue from green and yellow from pink. Unlike red-green color blindness, tritanomaly affects men and women equally and is not linked to the X chromosome.
Complete color blindness (achromatopsia) is very rare, affecting approximately 1 in 30,000 people. Those with achromatopsia see the world entirely in shades of grey. It is often accompanied by light sensitivity and reduced visual acuity.
This test includes plates for both red-green and blue-yellow color ranges. Your score breakdown shows which range — if either — your results suggest may be affected.
How this color blind test works
This test uses a simplified version of the Ishihara-style pseudoisochromatic plate method — the same approach used in clinical color vision screening. Each plate shows a circle filled with colored dots of varying sizes. Hidden within those dots is a number, formed by dots of a slightly different hue.
People with normal color vision can see the number clearly. People with red-green color vision differences may struggle to see numbers on the red-green plates, because the number dots and background dots appear the same color to them. The same principle applies to the blue-yellow plates.
For best results, set your screen to maximum brightness, remove any tinted glasses or lenses, and avoid glare on your screen. Ambient room lighting can also affect results — neutral white light is ideal. These plates are generated programmatically, so results may vary slightly from clinical Ishihara plates.
Tips for a more accurate result
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Maximum brightness
Set your screen to its highest brightness before starting. Low brightness compresses the color range and makes the test easier than it should be.
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Remove tinted lenses
Color-tinted glasses, blue-light filters, and night mode settings all shift color rendering and will affect your results. Disable them before testing.
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Neutral room lighting
Avoid taking the test in direct sunlight or under strongly colored lights. A neutral white LED or daylight bulb gives the most consistent results.
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Answer quickly
Clinical Ishihara tests are time-limited for a reason — prolonged staring can sometimes allow people to perceive numbers they wouldn't see at first glance.
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See an optometrist
An online test is a useful first step, not a diagnosis. An optometrist can perform a proper clinical evaluation using calibrated printed plates and additional tests.
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Retake if unsure
If lighting conditions changed mid-test or you were distracted, retake the test. Screen-based results can vary between sessions due to environmental factors.
Frequently asked questions
How accurate is an online color blind test?
Online color blind tests provide a useful initial screening, but results can be affected by your screen's color calibration, brightness settings, and the ambient lighting in your environment. Screen-based tests use RGB color mixing, whereas clinical Ishihara plates use carefully calibrated printed inks — the two are not identical. If this test suggests possible color vision differences, visit an optometrist for a formal assessment using printed plates under standardized lighting.
What are the types of color blindness?
The main types are red-green color blindness (deuteranomaly and protanomaly), which is the most common and affects roughly 8% of men. Blue-yellow color blindness (tritanomaly) is rarer and affects both sexes equally. Complete color blindness (achromatopsia) is very rare and involves seeing only in shades of grey. Most people with color vision differences have one of the red-green types, and many are unaware of it until they are tested.
Can color blindness be treated or cured?
Most inherited color blindness has no cure. However, special tinted lenses — such as EnChroma glasses — can help some people with red-green color blindness distinguish certain colors more easily in everyday life. They do not restore normal color vision but can improve color discrimination in specific situations. Acquired color vision loss (caused by eye disease, medication, or injury) may partially improve if the underlying cause is treated. An optometrist can advise on options based on your specific type and severity.
Is color blindness hereditary?
Most color blindness is inherited and present from birth. Red-green color blindness is caused by genes on the X chromosome, which is why it is significantly more common in men (who have one X chromosome) than women (who have two). Blue-yellow color blindness is caused by a gene on chromosome 7 and affects men and women equally. Color vision differences can also develop later in life due to certain diseases, medications, or physical damage to the optic nerve or retina.
Why does this test show Red-Green and Blue-Yellow plates?
The two most common categories of color vision deficiency affect different parts of the color spectrum. Red-green plates test the function of the L (red) and M (green) cone cells, which are the most frequently affected. Blue-yellow plates test the S (blue) cone cells, which are less commonly affected. Including both types gives a more complete picture of your color vision across the full visible spectrum.
How often should I get a professional eye exam?
Adults with no known vision problems should have a comprehensive eye exam every one to two years. Those with existing conditions, diabetes, a family history of eye disease, or who spend significant time on screens should see an optometrist more frequently. Children should have a vision screening before starting school. Many eye conditions, including glaucoma and macular degeneration, have no early symptoms — regular exams catch them before they cause lasting damage.
This tool is for informational purposes only.
Results may vary based on your screen's color rendering, brightness, ambient lighting, and other environmental conditions. This test is not a medical device and does not constitute a clinical diagnosis of color blindness or any other condition. If your results suggest possible color vision differences, consult a qualified optometrist or ophthalmologist for a professional evaluation.