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Red-Green Color Blindness

Being red-green colorblind means some reds, greens, oranges and browns are harder to tell apart. It is by far the most common kind of color blindness, and most people who have it still see plenty of color.

Red-green color blindness is an inherited difference in the red-sensitive (L) or green-sensitive (M) cones of the eye. It affects about 1 in 12 men and 1 in 200 women of Northern European ancestry. There are four types, from mild (deuteranomaly, protanomaly) to strong (deuteranopia, protanopia).

Last updated 2026-11-10

What does red-green colorblind look like?

These images show the same street with typical color vision and simulated with each red-green type. Look at the traffic light, the red car and the tree: with the stronger types they move toward similar olive and brown tones, while the blue sky stays clear.

Street scene, typical color vision: A red car, green tree and grass, blue sky and sign, yellow sun, pink and yellow flowers, and a traffic light with red, amber and green lamps lit.Typical color vision
Street scene, simulated moderate deuteranomaly: The red car turns orange-brown, the tree and grass turn olive, and the red and green lamps move closer in color.Simulated moderate deuteranomaly
Street scene, simulated deuteranopia: The red car and the tree turn similar olive tones and the red and green lamps look alike; the blue sky stays blue.Simulated deuteranopia
Street scene, simulated moderate protanomaly: The red car darkens to brown, the greens turn olive and the red lamp looks darker.Simulated moderate protanomaly
Street scene, simulated protanopia: The red car and red lamp turn dark olive brown, close to the tree and grass; the sky stays blue.Simulated protanopia
Simulations use the Machado, Oliveira & Fernandes (2009) model; "-anomaly" types are shown at moderate severity. Real experience varies from person to person and with your screen.

You can run the same filter on your own photos with our color blind simulator, or see more examples in what do colorblind people see.

Red-green colorblind vs normal vision

Typical color vision uses three cone types. Red-green color blindness changes how differently the red- and green-sensitive cones respond, so colors that differ mainly along the red-green direction look more alike.

Fruit bowl, typical color vision: A red apple, green apple, yellow lemon, orange, purple grapes, pink peach and blueberries in a blue bowl.Typical color vision
Fruit bowl, simulated deuteranopia: The red and green apples turn similar olive tones, pink turns gray and the purple grapes look blue.Simulated deuteranopia
Simulations use the Machado, Oliveira & Fernandes (2009) model. Real experience varies from person to person and with your screen.
  • Often confused: red with green, brown or orange; green with yellow or beige; dark red with brown or black (especially protan types).
  • Also affected: purple can look blue, and pink or teal can look gray, because their red or green component fades.
  • Still clear: blue versus yellow, and differences in lightness.

The four types of red-green color blindness

TypeWhat happensApprox. share of men*
DeuteranomalyGreen-sensitive cones shifted (mild to strong)~5%
ProtanomalyRed-sensitive cones shifted; reds look darker~1%
DeuteranopiaGreen-sensitive cones missing or not working~1%
ProtanopiaRed-sensitive cones missing or not working; reds look much darker~1%

*Approximate figures for men of Northern European ancestry (Birch, 2012). Rates are lower in many other populations.

Deutan types (green cones) are about three times as common as protan types (red cones). The main visible difference between the two is brightness: with protan types, reds look darker, so red text or red lights can be harder to notice.

How common is red-green color blindness?

Among people of Northern European ancestry it affects about 1 in 12 men and 1 in 200 women, making it the most common color vision deficiency. Blue-yellow color blindness, by comparison, affects fewer than 1 in 10,000 people.

What causes it?

Almost all red-green color blindness is inherited. The genes for the red and green cone pigments (OPN1LW and OPN1MW) sit next to each other on the X chromosome, and changes in them cause the protan and deutan types. Because it is X-linked, one altered copy is enough in men, while women usually need two, which explains the large difference between men and women. Read more in can women be color blind?

Color vision can also change later in life because of eye disease, some other health conditions or medicines. A new or changing color problem is different from inherited color blindness and should be checked by an eye doctor.

How do you test for red-green color blindness?

Eye care professionals use plate tests (such as Ishihara or HRR plates) and, to tell protan from deutan types and anomalous from complete types precisely, an anomaloscope. Our free red-green color blind test screens for both protan and deutan types and estimates severity in about three minutes.

Take the red-green test

Glasses, filters and everyday tips

  • Color blind glasses: notch-filter glasses can increase red-green contrast for some people with the milder types. They do not restore normal color vision, results vary, and they help least with protanopia and deuteranopia. What the research says about color blind glasses.
  • Phone and computer filters: built-in color filters can shift colors to make some red-green differences easier to see.
  • Color-identifier apps name the color under your phone camera.
  • Labels and patterns: ask for charts, maps and status lights that don’t rely on red versus green alone.
  • Traffic lights are usually read by position: on vertical lights, red is at the top and green at the bottom.

Red-green color blindness FAQ

What is red-green color blindness called?

The medical term is red-green color vision deficiency. It is split into protan types (protanomaly and protanopia), which involve the red-sensitive cones, and deutan types (deuteranomaly and deuteranopia), which involve the green-sensitive cones. An older name is daltonism, after the chemist John Dalton, who described his own color blindness.

Can red-green colorblind people see red and green?

Usually, yes. Most people with red-green color blindness see reds and greens, but some shades look alike, especially muted, dark or small areas of color. Only in the strongest types (protanopia and deuteranopia) do many reds, oranges, yellows and greens fall into similar tones.

Is red-green color blindness more common in men?

Yes. It affects about 1 in 12 men and 1 in 200 women of Northern European ancestry, because the genes involved are on the X chromosome. See our article on whether women can be color blind for how it is inherited.

Can red-green color blindness be cured?

There is currently no cure for inherited red-green color blindness. It is present from birth and normally stays the same. Glasses, phone color filters and color-identifier apps can help with specific tasks.

Can you drive if you are red-green colorblind?

In many places people with red-green color blindness can hold an ordinary driving license, and most learn to read traffic lights by the position of the lit lamp. Rules differ by country and are often stricter for professional licenses, so check with your local licensing authority.

Is there a red-green colorblind filter?

Yes, in two senses. Our color blind simulator is a filter that shows how a photo might look to someone who is red-green colorblind. Phones and computers also have built-in color filters for people with red-green color blindness that shift colors to make some differences easier to see.

Other types of color blindness

Sources

  1. MedlinePlus Genetics, U.S. National Library of Medicine. Color vision deficiency. medlineplus.gov
  2. National Eye Institute. Types of color vision deficiency. nei.nih.gov
  3. National Eye Institute. Color blindness. nei.nih.gov
  4. Birch J. Worldwide prevalence of red-green color deficiency. JOSA A. 2012;29(3):313–320. doi.org
  5. Nathans J, Piantanida TP, Eddy RL, Shows TB, Hogness DS. Molecular genetics of inherited variation in human color vision. Science. 1986;232(4747):203–210. pubmed.ncbi.nlm.nih.gov
  6. Simunovic MP. Colour vision deficiency. Eye. 2010;24(5):747–755. pubmed.ncbi.nlm.nih.gov
  7. Machado GM, Oliveira MM, Fernandes LAF. A physiologically-based model for simulation of color vision deficiency. IEEE TVCG. 2009;15(6):1291–1298. (Used for the simulated images.) doi.org

Note: this is a screening, not a diagnosis. Online tests can’t control your screen’s colors or brightness, so confirm any result with an eye care professional. Medical disclaimer · How the test works

More color vision tests

Color blind testFull screening: red-green and blue-yellow, with type and severity.Red-green color blind testDeeper check for protan and deutan types.Tritanopia testBlue-yellow (tritan) color vision screening.Color blind test for kidsShapes instead of numbers, for children who can’t read digits yet.Reverse color blind testHidden-figure plates that color blind people can see more easily.Color blind simulatorSee any photo the way people with color blindness see it.