Yes, there are several distinct types of color blindness, and they differ in which colors get confused, how severe the effect is, and what causes them. The most common category by far is red-green color blindness, but blue-yellow deficiencies and complete color blindness also exist. Roughly 1 in 12 men and 1 in 200 women have some form of color vision deficiency, adding up to about 300 million people worldwide.
Red-Green Color Blindness: Four Subtypes
Red-green color blindness is an umbrella term for four separate conditions, all involving the cone cells in your retina that detect red or green light. Two are mild, and two are severe.
Deuteranomaly is the single most common type of color vision deficiency. The green-detecting cones don’t work quite right, so certain shades of green look more red. Most people with deuteranomaly describe it as mild, and it rarely interferes with everyday tasks.
Protanomaly is the mirror version. The red-detecting cones are the ones that underperform, making certain reds look greener and less bright. Like deuteranomaly, it’s usually mild.
Deuteranopia and protanopia are the severe forms. In deuteranopia, the green cones are completely nonfunctional. In protanopia, the red cones are. Either way, the result is similar: you can’t reliably distinguish red from green at all. Traffic lights, ripe versus unripe fruit, and color-coded charts all become genuinely difficult to read.
Blue-Yellow Color Blindness
Blue-yellow deficiency is much rarer than the red-green type and involves the cone cells responsible for detecting short-wavelength (blue) light. It also comes in two forms. Tritanomaly is the milder version, where blue-detecting cones work but not optimally, making it hard to tell blue from green and yellow from red. Tritanopia means those blue cones are absent entirely, which makes blue look green and yellow look violet or light gray.
Unlike red-green deficiency, blue-yellow color blindness is inherited through a non-sex-linked gene, so it affects men and women at roughly equal rates.
Complete Color Blindness
The rarest form is called monochromacy, where two or all three types of cone cells don’t function. People with blue cone monochromacy still have working blue cones but lack functional red and green cones, leaving the world washed out with very limited color information. Achromatopsia, the most extreme version, means none of the cone types work properly. People with achromatopsia see entirely in shades of gray and often have additional problems like light sensitivity and reduced sharpness of vision.
Why Men Are Affected Far More Often
The genes that build your red-detecting and green-detecting cone pigments sit on the X chromosome. Men have one X chromosome, so a single faulty copy of one of these genes is enough to cause red-green color blindness. Women have two X chromosomes, meaning a working copy on the second X can compensate for a defective one on the first. This is why about 8% of men have red-green deficiency while fewer than 1% of women do. Fathers also cannot pass X-linked traits to their sons (sons get their father’s Y chromosome), so red-green color blindness typically passes from a carrier mother to her son.
Acquired Color Blindness
Not all color vision deficiency is inherited. You can develop it later in life if something damages the cones in your retina or the neural pathways connecting your eyes to your brain. Conditions linked to acquired color blindness include diabetes, macular degeneration, glaucoma, cataracts, multiple sclerosis, Parkinson’s disease, Alzheimer’s disease, sickle cell anemia, and chronic alcoholism. Certain medications can also shift color perception, particularly hydroxychloroquine, which is used for rheumatoid arthritis. Eye injuries, surgery, and radiation therapy are other potential causes.
Acquired color blindness can affect one eye more than the other and may worsen over time, unlike inherited forms, which stay stable throughout life. It also doesn’t follow the neat red-green or blue-yellow categories as predictably, since the damage depends on which part of the visual system is affected.
How It Shows Up in Daily Life
The practical effects depend heavily on which type you have and how severe it is. Someone with mild deuteranomaly might go years without realizing they see color differently. Someone with protanopia faces real challenges with anything color-coded: reading pie charts at work, picking out ripe produce, matching clothes, or interpreting dashboard warning lights.
In school, color-coded maps, graphs, and lab work can be frustrating. Professions that depend on precise color discrimination, like graphic design, electrical wiring, or piloting, may be difficult or restricted for people with more severe deficiencies. Safety-critical fields like construction and engineering often use color coding that assumes full color vision.
Driving is a common concern, but most people with color blindness learn to read traffic lights by position (top, middle, bottom) rather than color alone. The bigger risk comes from brake lights that blend into a red sunset or from LED signs that rely purely on color to convey meaning.
Testing and Diagnosis
The most familiar screening tool is the color plate test, where you look at a circle filled with colored dots and try to identify a number or shape hidden inside. Different plates target different types of deficiency. If the shape blends into the background and you can’t see it, that points to a specific category of color blindness.
For a more precise diagnosis, eye doctors use an anomaloscope test, where you look through an eyepiece and try to match the brightness of two lights using adjustment knobs. If you can’t get them to match, it confirms a deficiency and helps classify which type. A hue test, where you arrange colored blocks in rainbow order from red to purple, is often used for people whose jobs demand accurate color vision.
Corrective Options
Inherited color blindness has no cure. Specially tinted glasses designed for red-green deficiency can improve contrast between certain colors by filtering out overlapping wavelengths that confuse the brain. The effect varies widely from person to person. These glasses work only for people who still have some functioning red and green cones. If those cones are completely absent (as in protanopia or deuteranopia), the glasses won’t help. The color improvement also disappears as soon as you take them off, and because they reduce the total amount of light reaching your eye, wearing them at night isn’t ideal.
Gene therapy has successfully restored red-green color vision in monkeys, but it has not yet been tested in humans. For acquired color blindness, treating the underlying condition (removing a cataract, managing diabetes, switching medications) can sometimes restore some degree of color perception.