Red-Green Colorblind Test
This Ishihara-style test screens for all types of red-green color blindness, including protanopia, deuteranopia, protanomaly, and deuteranomaly. Red-green color deficiency is the most common form of color blindness, affecting approximately 8% of men and 0.4% of women worldwide.
Plate 1 of 10
What number do you see in the circle above?
Test Instructions
- Look at each colored circle
- Enter the number you see (if any)
- Take your time — there's no rush
- Make sure your screen brightness is normal
- Ensure good lighting conditions
Medical Disclaimer: This online test is a screening tool. While it can help identify potential color vision deficiencies, it is not a substitute for professional medical diagnosis. Screen brightness, lighting conditions, and display calibration can affect results.
What This Test Screens For
Red-green color vision deficiency encompasses four conditions: protanopia (red-blind), protanomaly (red-weak), deuteranopia (green-blind), and deuteranomaly (green-weak). All four involve difficulty distinguishing colors along the red-green axis because either the L-cones (protan types) or M-cones (deutan types) are absent or spectrally shifted. This test screens for all four simultaneously.
Limitations of This Test
This screening can identify the presence of a red-green deficiency but cannot determine the specific subtype (protan vs. deutan, anomalous vs. dichromatic). For precise classification, an anomaloscope test is needed. This test also cannot detect blue-yellow (tritan) deficiency. Screen calibration and lighting conditions affect accuracy.
What to Expect
You will see 10 circular plates filled with colored dots. Each plate contains a hidden number. Enter the number you see or indicate you see nothing. A score of 8-10 suggests normal red-green vision, while lower scores indicate possible deficiency. The test takes 2-3 minutes.
How Common Is Red-Green Colorblindness?
Red-green color vision deficiency is remarkably common, affecting about 1 in 12 men (8%) and 1 in 200 women (0.5%) of Northern European descent. The vast majority of cases are deuteranomaly (green-weak), which alone accounts for about 5% of men. The condition is X-linked recessive, explaining why males are disproportionately affected: they have only one X chromosome, so a single defective copy causes the condition.
The Four Types of Red-Green Deficiency
Protanopia and deuteranopia are the dichromatic (two-cone) forms, in which one cone type is completely absent. Protanomaly and deuteranomaly are the anomalous trichromatic (three-cone) forms, in which all cones are present but one has shifted spectral sensitivity. The anomalous forms are generally milder and more common than the dichromatic forms. All four types cause difficulty distinguishing reds from greens, browns, and certain blues from purples.
Frequently Asked Questions
What does a low score mean?
A score below 8 out of 10 suggests a red-green color vision deficiency. Lower scores generally indicate more severe deficiency. A score of 0-2 is consistent with dichromacy (protanopia or deuteranopia), while 3-7 may suggest anomalous trichromacy (protanomaly or deuteranomaly), though this is not definitive.
Can this test detect blue-yellow colorblindness?
No. This test uses plates designed for the red-green confusion axis only. People with blue-yellow deficiency (tritanopia, tritanomaly) will pass this test with a normal score. Use our blue-yellow colorblind test for tritan screening.
Why does red-green colorblindness affect more men than women?
The genes for red and green cone opsins are on the X chromosome. Males have one X chromosome, so a single defective copy causes the condition. Females have two X chromosomes, so both copies must be defective for full expression. This X-linked recessive pattern makes red-green deficiency about 16 times more common in men.
Related Tests
Protanopia Test (Red-Blind)
This Ishihara-style test screens for protanopia, the complete absence of red-sensitive (L) cones. If you have protanopia, you will have difficulty seeing the numbers hidden in these plates because the foreground and background colors fall along the red-green confusion axis.
Deuteranopia Test (Green-Blind)
This Ishihara-style test screens for deuteranopia, the complete absence of green-sensitive (M) cones. People with deuteranopia cannot distinguish the hidden numbers because the plate colors lie along the red-green confusion axis that their vision cannot resolve.
Protanomaly Test (Red-Weak)
This Ishihara-style test screens for protanomaly, a mild form of red-green color blindness where the red-sensitive (L) cones are present but spectrally shifted. People with protanomaly may have difficulty with some or all of these plates depending on the severity of their condition.
Deuteranomaly Test (Green-Weak)
This Ishihara-style test screens for deuteranomaly, the most common color vision deficiency worldwide. Deuteranomaly occurs when the green-sensitive (M) cones have a shifted spectral response, reducing the ability to distinguish between reds, greens, and similar hues.