What is the most common type of color blindness?

Deuteranomaly (green-weakness) affects about 5% of men. Together with protanomaly, about 8% of men have some color vision deficiency.

Why test for color blindness?

Testing ensures your designs are accessible to the ~8% of men with color vision deficiency, improving overall usability.

How many people have color vision deficiency?

Red-green deficiency (deuteranomaly and protanomaly) affects roughly 8% of men and 0.5% of women of Northern European descent. Blue-yellow types and total color blindness are far rarer, which is why designing for red-green confusion has the biggest impact.

What is the difference between protanopia and deuteranopia?

Both cause red-green confusion. Protanopia is the absence of red-sensitive (L) cones; deuteranopia is the absence of green-sensitive (M) cones and is the more common of the two. Reds and greens collapse toward similar olive and brown tones in each.

How do I stop relying on color alone?

Add a second cue: text labels such as Error and Success, distinct icons like ✓ and ✗, patterns or textures on chart segments, and differences in lightness rather than just hue. Anyone who cannot distinguish the hues still gets the information.

Which simulation should I test first?

Start with deuteranopia — it is the most prevalent red-green type and the most demanding. If red/green status indicators, charts and form validation still read clearly under it, they will usually hold up under the rarer deficiencies too.

Will increasing contrast help color-blind users?

Often yes. Differences in lightness survive color vision deficiency far better than differences in hue, so pairing colors that also differ in brightness keeps them distinguishable. Two colors with the same lightness but different hue are the classic failure case.

Color Blindness Simulator

How to use Color Blindness Simulator

Simulate how your design or image looks to users with different types of color vision deficiency — deuteranopia, protanopia, tritanopia, and monochromacy. Upload an image or enter a URL to preview it through each simulation filter. Helps identify color combinations that are indistinguishable to color-blind users before they reach production.

Upload an image (PNG, JPG, or WebP) or take a screenshot of your design.
Select a color vision deficiency type to simulate.
Compare the original and simulated views side by side.
Identify any UI elements (charts, status indicators, buttons) that rely solely on color.
Add text labels, patterns, or icons to supplement color-only distinctions.

Your data never leaves your device — 100% private processing.

Types of color vision deficiency

Deuteranopia (green-blind) and protanopia (red-blind) together affect approximately 8% of males and 0.5% of females of Northern European ancestry — these are the most important to design for. Both cause red and green to appear very similar (olive/brown tones). Tritanopia (blue-blind) is much rarer, affecting fewer than 1 in 10,000 people, and causes confusion between blue and yellow. Achromatopsia (total color blindness / monochromacy) is extremely rare — less than 1 in 33,000 — but designing for it produces highly accessible monochrome-friendly interfaces.

Type	Missing cone	Affected population	Colors confused
Protanopia	Red (L)	~1% males	Red and green
Deuteranopia	Green (M)	~6% males	Red and green
Tritanopia	Blue (S)	<0.01%	Blue and yellow
Achromatopsia	All cones	<0.003%	All colors

Designing for color accessibility

Never use color as the sole means of conveying information — always supplement with text labels, icons, patterns, or shape differences. Common failures: red/green traffic-light status indicators, pie/bar charts differentiated only by color, form validation that turns only the border red. Solutions: add a text label ("Error", "Success"), use distinct icons (✓ ✗), increase the lightness contrast between the colors (not just hue), and add a pattern or texture fill to chart segments. Test with the deuteranopia simulation first — it's the most prevalent and the most challenging.

Worked examples

Red/green status badges

Inputs: green "OK" + red "Error" badges

Result: deuteranopia: both shift toward similar olive/brown

Traffic-light chart

Inputs: red, amber, green segments

Result: protanopia: red and green become hard to tell apart

Glossary

Deuteranopia: A color vision deficiency caused by absent or non-functional green-sensitive (M) cone cells — most common type.
Protanopia: Absence of red-sensitive (L) cones, causing red and green to appear similar.
Tritanopia: Absence of blue-sensitive (S) cones, affecting blue-yellow discrimination — very rare.
Color-blind safe palette: A set of colors chosen to remain distinguishable under the most common forms of color vision deficiency.

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Color Blindness Simulator

How to use Color Blindness Simulator

Types of color vision deficiency

Designing for color accessibility

Worked examples

Glossary

Related reading

Frequently Asked Questions

Why use Color Blindness Simulator?

Common use cases

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