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Detect Color Blindness

Red-Green Color Blind Test

The most common colour deficiency, by far. These plates focus on the red-green axis to screen for protan and deutan types. Read each number and tap what you see.

Plate 1 of 10

What number do you see?

No timer · answers stay on your device

Tip: view in good lighting at 100% screen brightness for the most reliable result.

Not a medical diagnosis. This is an educational screening tool, not a clinical exam. Screen brightness, colour settings and lighting all affect the result. For anything that matters, a driving or aviation medical, a job requirement, or a health concern, book a professional colour-vision test with an optometrist or ophthalmologist.

What red-green color blindness is

Red-green colour vision deficiency happens when the red-sensitive (L) or green-sensitive (M) cones in the retina are missing or shifted. Because the genes for these cones sit on the X chromosome, the condition is far more common in men, about 1 in 12 men (8%) and 1 in 200 women.

It comes in four sub-types, from mild to strong:

  • Deuteranomaly: reduced green sensitivity; the most common and usually mild.
  • Protanomaly: reduced red sensitivity; reds look dim.
  • Deuteranopia: no working green cones; a strong deficiency.
  • Protanopia: no working red cones; reds can look almost black.

How this test tells them apart

The plates are built so the hidden number only separates from the background by hue along the red-green confusion line, at matched brightness. If you consistently miss those numbers, the test estimates whether the pattern leans protan or deutan and how strong it is. Online screening can't fully separate the two sub-types, that needs an anomaloscope or an arrangement test, but it's a reliable first check.

Want the full picture? Take the complete color blind test, which also screens the blue-yellow axis, or read about each type of colour blindness.

Frequently asked questions

What is red-green color blindness?
It's the most common form of colour vision deficiency, where reds and greens are hard to tell apart. It comes in four sub-types, protanomaly, protanopia, deuteranomaly and deuteranopia, depending on which cones are affected and how strongly.
Is red-green color blindness common?
Very. It affects about 1 in 12 men (8%) and 1 in 200 women, because the genes involved sit on the X chromosome.

Keep exploring

What next?

Take the color blind test 14 quick plates · instant type & severity · no sign-up. Start the test → See how you see colour Simulate protan, deutan, tritan & more on any image. Open the simulator → Do colour blind glasses work? Honest comparison of EnChroma, Pilestone & ColorLite. Read the guide →