Most people with color blindness have one of four types of red-green deficiency, and the specific type depends on which color-sensing cells in your eyes are affected and how severely. About 8% of men and 0.5% of women of Northern European descent have some form of red-green color blindness, making it far more common than blue-yellow or total color blindness. Figuring out your exact type requires understanding what each one looks like in daily life and, ideally, getting the right diagnostic test.
Red-Green Color Blindness: The Four Types
Red-green deficiency accounts for the vast majority of color blindness cases, but it actually breaks down into four distinct types split across two categories: mild versions where one type of color receptor is weakened, and severe versions where it’s missing entirely.
Deuteranomaly is the single most common type, affecting up to 6% of males in some populations. Your green-sensitive receptors are present but shifted in sensitivity, which makes certain greens look more red or muddy. Most people with deuteranomaly describe it as mild. You can still see a wide range of colors, but you may struggle to distinguish between greens, yellows, and some reds, especially in dim lighting or with muted shades.
Protanomaly is less common, found in roughly 1% of males. Here, your red-sensitive receptors are weakened rather than your green ones. Certain reds look more green and noticeably less bright. This dimming of red is a key difference from deuteranomaly. If reds seem darker or duller than other people describe them, protanomaly is a likely candidate.
Deuteranopia and protanopia are the more severe forms. In these cases, one type of receptor is missing entirely rather than just shifted. Both make it impossible to tell red from green at all. The practical difference between the two is subtle: protanopia causes reds to appear darker and more muted, while deuteranopia doesn’t dim reds the same way. Both are less common than their milder counterparts.
Blue-Yellow and Total Color Blindness
Blue-yellow color blindness, called tritanopia or tritanomaly, is extremely rare, affecting fewer than 0.01% of the population. It involves your blue-sensitive receptors and makes it hard to distinguish blue from green or yellow from violet. Unlike red-green deficiency, blue-yellow color blindness is inherited through a non-sex-linked chromosome, so it affects men and women at equal rates.
Total color blindness (monochromacy or achromatopsia) is rarer still. People with this condition see the world in shades of gray and often have additional symptoms: sensitivity to bright light, reduced sharpness of vision, and sometimes involuntary eye movements. If you’re reading this article, total color blindness is very unlikely to be your type, since most people with it are diagnosed in early childhood due to those other noticeable symptoms.
How to Tell Your Specific Type
Online color plate tests can tell you whether you have a color deficiency, but most of them can’t reliably tell you which kind. The classic Ishihara test, the one with colored dots forming numbers, is good at detecting red-green deficiency but cannot distinguish between protan and deutan types, and it misses blue-yellow deficiency entirely.
If you want a more specific answer, a few tests go further. The Richmond Hardy-Rand-Rittler (HRR) test evaluates all three color axes (red-green and blue-yellow) and can grade your deficiency as mild, moderate, or severe. The Farnsworth-Munsell 100-Hue test measures your overall color discrimination ability by having you arrange colored caps in order. It’s thorough but time-consuming. The gold standard is a device called an anomaloscope, which has you match colors by adjusting light mixtures and can precisely identify whether you’re protan or deutan.
An eye care provider can run these tests in about 10 to 30 minutes depending on which ones they use. If you’ve only ever taken a free online screening, it’s worth getting a proper evaluation to learn your exact type and severity.
Clues From Your Daily Experience
While a formal test gives the definitive answer, your everyday color confusion patterns offer strong hints. If you mix up reds and greens but reds also seem unusually dark or dim, you likely fall on the protan side. If reds appear normal in brightness but greens, oranges, and browns blur together, you’re more likely deutan. If blues and yellows are your trouble colors while reds and greens seem fine, you may have a tritan deficiency.
Common real-world frustrations that help narrow it down: confusing traffic light colors (especially the difference between the green and the yellow) points to red-green types. Struggling with color-coded charts, picking mismatched clothes, or not seeing the ripe red of strawberries against green leaves are classic red-green experiences. Having trouble telling the difference between blue and purple, or yellow and light green, suggests the rarer blue-yellow type.
Why You Have It
Red-green color blindness is passed through the X chromosome, which is why it overwhelmingly affects men. Males have only one X chromosome, so a single copy of the gene causes the condition. Females need the gene on both X chromosomes to be color blind, which requires inheriting it from both parents. Women who carry the gene on one X chromosome typically have normal color vision but can pass the trait to their sons.
Blue-yellow deficiency follows a different inheritance pattern and is not sex-linked, so it affects men and women equally. Rates vary across populations: red-green deficiency reaches 8 to 10% in men of European, Russian, and Norwegian descent, drops to about 4% in East Asian populations, and falls below 2% in some Aboriginal Australian and Central African groups.
Color vision can also change later in life without a genetic cause. Cataracts, glaucoma, macular degeneration, multiple sclerosis, and certain medications can all degrade color perception over time. If your color confusion started in adulthood or seems to be getting worse, an underlying eye or neurological condition may be involved rather than genetics.
Do Color-Correcting Glasses Work?
Glasses marketed for color blindness, like EnChroma, use special filters to shift the wavelengths of light entering your eyes, aiming to make reds and greens more distinguishable. In practice, the results are mixed. A controlled study found that the filters only improved performance for people with protanopia (the severe red-absent type) on one specific test, and actually made color naming worse for all participants when it came to blue-green (cyan) colors. For people with deutan deficiency, the most common type, the filters didn’t clearly improve color discrimination and in some cases shifted errors from one category to another.
Some users still report a subjective “wow” experience when first wearing them, but the scientific evidence doesn’t support the claim that these filters correct color blindness. They also do nothing for blue-yellow or total color blindness. Practical adaptations, like labeling clothes with color tags, using apps that identify colors through your phone camera, or memorizing the position order of traffic lights, tend to be more reliable day-to-day strategies.