Color Blindness Simulator

Who This Tool Is Designed For

Color Vision Deficiency (CVD) affects approximately 300 million people worldwide (Colour Blind Awareness Organisation). Roughly 8% of males and 0.5% of females of Northern European descent have some form of CVD (Birch, 2012). Designers, developers, and content creators use CVD simulation to verify that their work remains usable and distinguishable for people who cannot perceive certain colour distinctions. This is also relevant to WCAG 2.2 SC 1.4.1 (Use of Color), which states that color must not be the sole means of conveying information.

Types of CVD (Prevalence Data)

• Protanopia (~1.3% of males) · Absence of red (L-cone) photopigment. Reds appear dark or brownish; red–green distinction is lost.
• Deuteranopia (~1.2% of males) · Absence of green (M-cone) photopigment. The most common form of CVD. Green–red and green–brown distinctions are lost.
• Tritanopia (~0.01% of population) · Absence of blue (S-cone) photopigment. Blues appear greenish; yellow–blue distinction is lost. Not sex-linked.
• Achromatopsia (~0.003% of population) · Complete absence of cone function (rod monochromacy). Sees only shades of grey, with high light sensitivity.

Research Citations

• Brettel, H., Viénot, F. & Mollon, J.D. (1997). "Computerized simulation of color appearance for dichromats." Journal of the Optical Society of America A, 14(10), 2647–2655. · The standard algorithm for simulating dichromatic vision, used by major accessibility testing tools including axe, Lighthouse, and Stark.
• Viénot, F., Brettel, H. & Mollon, J.D. (1999). "Digital video colourmaps for checking the legibility of displays by dichromats." Color Research & Application, 24(4), 243–252. · Extended the 1997 algorithm to real-time video and display simulation.
• Birch, J. (2012). Worldwide prevalence of red-green color deficiency. Journal of the Optical Society of America A, 29(3), 313–320. · Comprehensive meta-analysis of CVD prevalence across populations.
• Colour Blind Awareness Organisation. "About Colour Blindness." colourblindawareness.org · Estimates 300 million people affected worldwide; 4.5% of the entire population.
• W3C (2023). "WCAG 2.2 SC 1.4.1 · Use of Color (Level A)." · Requires that colour is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.

Disclaimer

This tool provides an approximation of CVD perception using established computational models. Actual perception varies between individuals depending on the degree of photopigment loss (anomalous trichromacy vs. dichromacy). Simulation on a typical sRGB display cannot fully replicate the experience of CVD. This tool does not diagnose any condition. For clinical assessment of colour vision, consult a qualified optometrist or ophthalmologist.