Color Blindness Simulator & Checker

Color blindness (color vision deficiency) is usually inherited through X-linked recessive genes, which is why it affects roughly 8% of men but only 0.5% of women. The condition occurs when one or more types of cone cells in the retina are absent or dysfunctional. The three cone types respond to red (long), green (medium), and blue (short) wavelengths. Most color blind individuals are not truly 'blind' to color but perceive a reduced range of distinguishable hues.

These are the three types of dichromacy (complete absence of one cone type). Protanopia lacks red-sensitive cones, making reds appear dark and indistinguishable from greens. Deuteranopia lacks green-sensitive cones with similar red-green confusion but without the darkening. Tritanopia lacks blue-sensitive cones, causing blue-yellow confusion. Protanopia and deuteranopia are far more common (affecting ~2% and ~6% of males respectively) while tritanopia is rare (~0.01% of the population).

Approximately 300 million people worldwide have some form of color vision deficiency. If information is conveyed only through color — like red for errors and green for success — these users may miss critical feedback. Accessible design uses multiple cues: icons, patterns, labels, and sufficient contrast alongside color. WCAG guidelines recommend a minimum contrast ratio of 4.5:1 for text and advise never using color as the sole means of conveying information.