Most colorblind people see a full world of color, just a narrower version of it. Rather than seeing in black and white, the vast majority experience certain colors blending together or appearing as the same shade, while other colors look perfectly normal. About 1 in 12 men and 1 in 200 women have some form of color vision deficiency, and what they actually see depends on which type they have.
How Color Vision Works
Your eyes have three types of color-detecting cells called cones. Each type responds most strongly to a different range of light wavelengths: one peaks around 420 nanometers (short wavelengths, roughly blue light), another around 545 nanometers (medium wavelengths, green light), and the third around 576 nanometers (long wavelengths, red light). Your brain compares the signals from all three cone types and interprets the differences as color. When one type of cone is missing or doesn’t function correctly, the brain receives less contrast between certain wavelengths, and colors that should look distinct end up looking the same.
Red-Green Color Blindness
Red-green deficiency is by far the most common type, accounting for the vast majority of all cases. It comes in two forms depending on which cone is affected, and each creates a slightly different pattern of color confusion.
Protanopia (Red-Weak or Red-Absent)
People with protanopia have reduced or absent sensitivity to red light. Reds appear much darker than they do to someone with typical vision, and can look nearly black. Dark brown, dark green, dark orange, dark red, and dark blue all blend together into a murky, hard-to-distinguish range. Some blues get confused with reds, purples, and dark pinks. Mid-greens can look the same as certain oranges. The overall effect is that the red end of the spectrum loses its vibrancy and warmth, collapsing into darker, muddier tones.
Deuteranopia (Green-Weak or Green-Absent)
Deuteranopia affects the green-sensitive cones and produces a different set of confusions. Mid-reds blend with mid-greens, which is the classic “can’t tell red from green” experience most people associate with color blindness. But it goes well beyond that. Bright greens can look yellow. Blue-greens get confused with grey and mid-pinks. Pale pinks become hard to distinguish from light grey or white. Light blues blend with lilac. Mid-reds also look similar to mid-brown. The world isn’t grey; it’s full of color, but the palette is shifted and compressed so that many hues that look obviously different to a typical eye appear identical.
Blue-Yellow Color Blindness
Tritanopia is much rarer and affects the short-wavelength cones responsible for detecting blue light. People with this type struggle to distinguish blue from green, red from purple, and pink from yellow. Colors also tend to appear less bright overall. While red-green deficiency compresses the warm-to-cool middle of the spectrum, tritanopia removes contrast at the blue end, making blues and yellows lose their distinctness. Someone with tritanopia might see a bright blue sky and green grass as closer to the same color.
Total Color Blindness
Complete achromatopsia is the only form that matches the popular image of color blindness. People with this condition cannot perceive any color at all. They see exclusively in black, white, and shades of grey. But achromatopsia is extremely rare and comes with additional visual challenges: high sensitivity to light and glare, involuntary eye movements, and significantly reduced sharpness of vision. Many people with achromatopsia also have a small blind spot in their central vision, along with farsightedness or nearsightedness. This is a fundamentally different condition from the much more common red-green or blue-yellow deficiencies.
How Colorblind People Navigate Daily Life
One of the first questions people ask is about traffic lights, and the answer is straightforward: colorblind drivers rely on the position of the light rather than its color. Red is always on top, green on the bottom. Research on colorblind drivers found that they had no difficulty recognizing signals at close range, though they noticed and identified signals more slowly from a distance compared to people with typical vision. Colorblind drivers also tended to pay more attention to traffic signals and the movement of surrounding cars, compensating with extra caution.
Everyday tasks like judging whether fruit is ripe, matching clothes, reading color-coded charts, or interpreting maps can be genuinely frustrating. A banana turning from green to yellow might not register a change. A pie chart using red and green slices looks like one solid block. Many colorblind people develop workarounds over a lifetime: memorizing the order of items, asking for help in specific situations, or relying on labels and context clues rather than color alone.
Color-Correcting Glasses
Glasses with specially engineered filters can improve color perception for people with red-green deficiency. These lenses work by blocking narrow bands of light where the red and green cone responses overlap most, which increases the separation between the two color channels. The result is that colors appear more distinct and vibrant. A study conducted by UC Davis Eye Center in collaboration with France’s INSERM found that after two weeks of wearing these filtered glasses, users showed enhanced ability to identify and distinguish colors. Notably, some of that improvement persisted even after taking the glasses off, suggesting the brain may partially recalibrate its color processing with extended use.
These glasses work best for people who still have all three cone types but with shifted or overlapping sensitivity (the most common form of red-green deficiency). They don’t help people whose cones are completely absent, and they don’t work for blue-yellow or total color blindness.
Digital Tools and Screen Adjustments
Most operating systems now include built-in color filters specifically designed for different types of color blindness. Windows, macOS, iOS, and Android all offer options to shift on-screen colors into ranges that are easier to distinguish. Additional display modes like high contrast, inverted colors, and dark mode can also help, though their effects vary by person and deficiency type.
On the design side, accessibility guidelines push developers to never rely on color alone to convey information. That means pairing colors with patterns, labels, or icons so that a colorblind user can still interpret a chart, distinguish a link from regular text, or tell the difference between error and success messages. Sufficient contrast between text and backgrounds matters too. Thin or lightweight fonts have inherently lower legibility, especially for people with any kind of vision difference, so higher contrast ratios help compensate.