Types of colour blindness
| Type | Affects | Prevalence |
|---|---|---|
| Deuteranopia / -anomaly | Green cones — red/green confusion | ≈6% of men |
| Protanopia / -anomaly | Red cones — reds look dark | ≈2% of men |
| Tritanopia | Blue cones — blue/yellow confusion | Rare |
| Achromatopsia | No colour vision | Very rare |
Design tips
- Never use colour alone for meaning: add labels, icons or patterns to charts, errors and status badges.
- Red + green is the most common problem pair; blue + orange works for almost everyone.
- Keep text contrast at WCAG AA or higher — check it with the Contrast Checker.
Frequently asked questions
How many people are colour blind?
About 1 in 12 men and 1 in 200 women have some form of colour vision deficiency.
Is my image uploaded?
No, the simulation is calculated in your browser.
How accurate is it?
It uses the peer-reviewed Machado, Oliveira & Fernandes model at full severity; real perception varies between people.