Deuteranopia · deutan dichromacy
Deuteranopia (green-blind)
Without the medium-wavelength M cones, red and green are hard to tell apart — but unlike protanopia, red keeps nearly its normal brightness.
- Missing cones
- M (medium wavelength, green)
- Inheritance
- X-linked recessive
- Prevalence
- Men ~1.3% · women ~0.01%
- Neutral point
- ~498 nm (blue-green) looks gray
How it works
In deuteranopia, the M-cone photopigment (OPN1MW gene) does not work, so color is judged with only the L and S cones — a form of dichromacy.
Because the L cones carry much of the sense of brightness, red does not look dark as it does in protanopia. So although the two types confuse similar colors, they differ on one question: “Does red look dark?”
Blue-green around 498 nm becomes a neutral point that can't be distinguished from gray.
What you see
Red, orange, yellow, and green converge into yellowish tones, and green comes to resemble gray and beige. Purple and blue also draw closer.
In the table below, red and green both turn into a similar ochre, but red stays brighter than in the protanopia simulation.
| Color | Normal vision | Deuteranopia (green-blind) |
|---|---|---|
| Red | #D7263D | #8A7D37 |
| Orange | #F28C28 | #C3AF28 |
| Yellow | #F2CD37 | #EDD441 |
| Green | #2E9E44 | #93864B |
| Teal | #1A9E9A | #82889B |
| Blue | #2F6BD8 | #0068D6 |
| Purple | #7E3FB2 | #245EAF |
| Pink | #E86FA6 | #9FA0A3 |
| Brown | #8B5A2B | #75692C |
| Gray | #8C8C8C | #8C8C8C |
Simulation: Machado, Oliveira & Fernandes (2009) matrices at 100% severity. Results may differ from reality depending on your monitor and individual differences.
How common is it?
It is reported in about 1.3% of men and about 0.01% of women of European ancestry (Sharpe et al., 1999).
For red-green deficiency as a whole, rates in East Asian men are reported to be somewhat lower than in men of European ancestry (Birch, 2012).
Easily confused colors
- Red ↔ green ↔ brown ↔ orange
- Green ↔ gray/beige, blue-green ↔ gray
- Purple ↔ blue, pink ↔ gray
Everyday tips
- Judge fruit ripeness and meat doneness by firmness, smell, or a thermometer rather than by color. Everyday life guide
- Blue-orange contrast is easy to see even with deuteranopia. These two colors work well for markings and notes.
- Some careers have color vision standards, so check the relevant organization's requirements before choosing a path. Careers guide