OKLCH Studio
Color blindness simulator
About one in twelve men has some red-green color vision deficiency. A pair that looks obvious in full color can collapse into one shade. These previews use the same approximate matrices as the studio. They are a check, not a diagnosis. Luminance contrast still has to pass on its own: color must not be the only signal.
Contrast of this pair is 15.50:1 and passes WCAG AA for normal text. Open it in Contrast Fix
Normal
The quick brown fox jumps over the lazy dog
DeleteSave
Protanopia
The quick brown fox jumps over the lazy dog
DeleteSave
Deuteranopia
The quick brown fox jumps over the lazy dog
DeleteSave
Tritanopia
The quick brown fox jumps over the lazy dog
DeleteSave
Achromatopsia
The quick brown fox jumps over the lazy dog
DeleteSave
What the three modes change
Protanopia and deuteranopia both reduce the difference between red and green. Protanopia also darkens reds. Tritanopia reduces the difference between blue and yellow and is much rarer.
If Delete and Save become hard to tell apart, add a label, an icon, or a lightness difference. The contrast checker measures that lightness. Passing AA does not mean the hues are distinguishable, and distinguishable hues do not mean the contrast passes.
Questions
What do these previews change?
Protanopia and deuteranopia reduce the difference between red and green. Protanopia also darkens reds. Tritanopia reduces the difference between blue and yellow. Achromatopsia here is a luminance-only view: hue is removed, so only lightness remains. These are approximate filters, not a diagnosis.
Does a WCAG pass mean the hues stay distinct?
No. WCAG contrast measures lightness, not whether two hues stay apart under a colour-vision deficiency. A pair can pass AA and still collapse into one shade, and two hues can look different while the contrast still fails.
Is this a medical test?
No. It is a design check that reuses the studio's approximate matrices, plus a grayscale view for achromatopsia. It does not measure anyone's vision.