What causes color blindness?
Color blindness (color vision deficiency) occurs when one or more types of cone cells in your retina are absent or function differently. Most cases are genetic and affect about 8% of men and 0.5% of women of Northern European descent.
The three main types
Protanopia and Protanomaly (Red-weak): Reduced sensitivity to red light. Reds appear darker and can be confused with greens, browns, and blacks. About 1% of men have protanopia (complete red cone absence) and 1% have protanomaly (partial red cone function).
Deuteranopia and Deuteranomaly (Green-weak): Reduced sensitivity to green light. Greens can be confused with reds and yellows. This is the most common form, affecting about 6% of men. Deuteranomaly (partial) is far more common than deuteranopia (complete).
Tritanopia and Tritanomaly (Blue-weak): Reduced sensitivity to blue light. Blues can be confused with greens, and yellows with purples. This is rare, affecting less than 0.01% of the population. Uniquely, it affects men and women equally because it is not linked to the X chromosome.
How to get tested
Our Color Blindness Test provides a quick screening using patterns inspired by Ishihara plates. While this cannot replace a clinical examination, it can indicate whether professional testing is warranted.
For a definitive diagnosis, see an optometrist or ophthalmologist who can perform an Ishihara test (printed plates), an anomaloscope test, or a Farnsworth D-15 test.
Living with color blindness
Color blindness is not a disability for most daily activities. Most people with color vision deficiency adapt and function normally. However, certain professions (airline pilot, electrician, some medical fields) require normal color vision.
Modern technology helps: most operating systems and smartphones include color blindness accessibility filters that shift colors to be more distinguishable. Many apps and games now include colorblind-friendly modes.