Deutan Test (Green-Weak)
A focused screening for deuteranomaly, the green-weak type of color vision deficiency, and the most common of all. Read the number in each plate; we'll estimate whether your green-axis discrimination looks typical.
You'll see 10 plates of colored dots. For each one, tap the number you see, or "I can't see a number." Go with your first impression; each plate has a short timer.
Some plates show no number to most people, and “I can't see a number” is a normal, expected answer, not a failure.
Best on a phone or laptop at full screen brightness. Keyboard: press a number key, or Enter if you can't see one.
What deutan vision is like
Deutan color vision deficiency comes from the green-sensitive cones. In deuteranomaly (the mild-to-moderate form) those cones are shifted toward the red part of the spectrum, so the eye gets less separation between reds and greens. In deuteranopia (the rarer, stronger form) the green cones are effectively missing.
Day to day this often shows up as:
- Greens, browns and khakis looking similar
- Red text on a green background being hard to read
- Muted or "washed out" reds and greens
Deutan deficiency is inherited on the X chromosome, which is why it's far more common in men. Most people with it have completely normal visual sharpness; it's specifically the red-green discrimination that's reduced.
Frequently asked
What is deuteranomaly?
Deuteranomaly is the most common type of color vision deficiency. The green-sensitive (M) cones are shifted toward red, so greens, browns, oranges and reds can look more alike. Most people with it have only mild difficulty and full, sharp vision otherwise.
How is a deutan test different from a general color blind test?
A deutan-focused test uses only green-axis (deutan) plates plus control plates, so more of your answers bear on that one axis. It is a screening tool, not a diagnosis, and screen brightness and calibration affect the result.
Is deuteranomaly the same as being fully colorblind?
No. Deuteranomaly is a reduced ability to tell certain greens and reds apart, not an absence of color. Complete color blindness (monochromacy) is rare and different.