Roughly 1 in 12 men and 1 in 200 women are born with some form of color blindness, making it one of the most common inherited visual differences in the world. A large 2025 meta-analysis published in Ophthalmology, pooling decades of screening data from children and adolescents, put the overall global prevalence at about 2.6%. But that number masks a dramatic split between the sexes and meaningful variation across populations, types, and age groups.
Why Men Are Far More Likely to Be Colorblind
Color blindness is overwhelmingly an X-linked genetic trait. Because men carry only one X chromosome, a single copy of the gene variant is enough to affect their color vision. Women have two X chromosomes, so a working copy on one can compensate for a faulty copy on the other. The 2025 global analysis found congenital color vision deficiency in 4.38% of boys and 0.64% of girls, roughly a seven-to-one ratio. Among European populations, the gap is even wider: about 8% of men versus 0.4% of women.
Women can still be colorblind, but most affected women are carriers who pass the trait to their sons without experiencing it themselves. A woman needs to inherit the variant from both parents to have full red-green color blindness, which is statistically uncommon.
Red-Green Deficiency Dominates
About 99% of all inherited color blindness falls into the red-green category. Within that, there are two main subtypes. The more common one, called deutan deficiency, affects the green-sensitive cells in the retina. Global data show it in about 3.66% of males and 0.46% of females. The less common type, protan deficiency, affects red-sensitive cells and appears in roughly 1.54% of males and 0.30% of females.
People with red-green color blindness don’t necessarily see the world in black and white. Most have a milder form where certain shades of red, green, brown, and orange blend together or look muted. Picking a ripe tomato from a vine, reading color-coded charts, or distinguishing traffic light colors at a distance can be genuinely difficult, but the severity varies widely from person to person.
Blue-yellow color blindness (tritan deficiency) is far rarer, showing up in roughly 0.67% of males in global data. Total color blindness, known as achromatopsia, where a person sees only shades of gray, affects approximately 1 in 30,000 people worldwide. One notable exception: between 4 and 10 percent of Pingelapese islanders in Micronesia have complete achromatopsia, likely due to a genetic bottleneck in the small population’s history.
Rates Vary by Ethnic Background
Color blindness prevalence is not uniform across populations. Large surveys consistently find the highest rates among European Caucasians, at about 8% of men. Chinese and Japanese men show rates between 4% and 6.5%, depending on the region surveyed. African American men were historically cited at around 4%, but surveys conducted after 1960 place the figure between 6% and 7.2%, closer to the European average. In Nigeria, one study found 7.1% among men in Lagos, rising to nearly 8% in men of mixed Nigerian and European ancestry.
Indigenous and isolated populations tend to have lower rates. Screening of over 4,400 Native Australian and Papua New Guinean men in 1965 found prevalence around 2%. In South America, nomadic tribes at high altitudes showed rates below 2%, while settled coastal communities were closer to 5%, and port populations with historical European intermarriage reached 8%. These patterns suggest that gene flow from European populations, where the trait is most common, has gradually shifted rates upward in many mixed-ancestry groups.
Acquired Color Blindness After Age 40
Not all color vision loss is genetic. Acquired color vision deficiency develops from eye disease, neurological conditions, or simply aging. The eye’s lens naturally yellows over time, absorbing more blue and violet light, which progressively dulls the perception of shorter-wavelength colors. This is why older adults often struggle to distinguish blues from purples or notice subtle color shifts they could see easily in their twenties.
Conditions like glaucoma, macular degeneration, diabetic eye disease, cataracts, and certain neurological disorders can all damage color perception. Some medications can too. While precise numbers are scarce, researchers believe acquired color vision deficiency is actually more common than the inherited form in populations over 40. Because it develops gradually, many people never realize their color perception has changed.
How Color Blindness Is Detected
The standard screening test has been the Ishihara plate test for over a century: a series of circles filled with colored dots, with a number or pattern hidden inside that only people with normal color vision can read. It’s quick, cheap, and effective. Studies show it has a sensitivity of about 96% for detecting color vision deficiency, meaning it catches the vast majority of cases. Newer digital versions perform comparably, with concordance rates around 88% when matched against the traditional plates.
Despite the test’s accuracy, many people go undiagnosed well into adulthood simply because routine vision screenings in schools and primary care don’t always include color vision checks. Children, in particular, may not realize that the way they see colors is different from anyone else’s. They develop workarounds, like memorizing the position of traffic lights or relying on brightness rather than hue, and may not discover they’re colorblind until a formal screening or an offhand comment from a friend.
Severity Ranges Widely
Color blindness isn’t a single experience. The 2025 global data broke severity into three tiers. Dichromacy, where one type of color-sensing cell is entirely missing, appeared in about 1.59% of males. Anomalous trichromacy, a milder form where all three cell types are present but one responds to a shifted range of wavelengths, showed up in 1.17% of males. Monochromacy, the near-total absence of color perception, was the rarest at 0.36% of males.
For women, anomalous trichromacy was most common at 0.38%, followed by dichromacy at 0.27% and monochromacy at 0.10%. In practical terms, someone with anomalous trichromacy might confuse certain shades but navigate daily life with minimal trouble, while someone with dichromacy could find entire categories of color indistinguishable. Monochromacy, the most severe form, often comes with additional symptoms like light sensitivity and reduced visual sharpness.