Types of Color Blindness
Color vision deficiencies vary by which cone signals are reduced or missing. Compare red-green, blue-yellow, and complete color blindness, then open any type for symptoms, prevalence, daily-life examples, and practical tips.
Red-Green Color Blindness
The most common group. It includes protan and deutan deficiencies, which make reds, greens, browns, oranges, and some purples harder to tell apart.
4 types: Protanopia, protanomaly, deuteranopia, deuteranomaly
Blue-Yellow Color Blindness
A rarer group that affects blue-yellow discrimination. Blues may look greener, yellows may look lighter, and purple can be difficult to separate from red.
2 types: Tritanopia, tritanomaly
Complete Color Blindness
The rarest group. Complete color blindness, often called achromatopsia, means little or no hue perception and may also involve light sensitivity or reduced sharpness.
1 types: Achromatopsia
Compare Symptoms
Use the type cards below to compare confused colors, affected cones, and common daily-life examples.
Take a Screening Test
If you are not sure where to start, take the free online color blind test and use the result as a screening guide.
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Online tests are not a diagnosis. New, sudden, or worsening color vision changes should be checked by an eye care professional.
Red-Green Color Blindness
Protanopia
(Red-Blind)Prevalence: ~0.56% of the population
Protanopia is a type of red-green color blindness in which the long-wavelength (L) cones in the retina are completely absent or nonfunctional. People with protanopia cannot perceive red light, causing reds to appear dark or nearly black and making it difficult to distinguish between reds, greens, and browns.
Deuteranopia
(Green-Blind)Prevalence: ~0.67% of the population
Deuteranopia is the most common type of dichromatic color vision deficiency. It occurs when the medium-wavelength (M) cones, responsible for perceiving green light, are completely absent or nonfunctional. People with deuteranopia have difficulty distinguishing between reds and greens, though unlike protanopia, they do not experience the characteristic darkening of the red spectrum.
Protanomaly
(Red-Weak)Prevalence: ~0.57% of the population
Protanomaly is a mild form of red-green color blindness in which the long-wavelength (L) cones are present but have a shifted spectral sensitivity, peaking closer to the medium-wavelength range. This anomalous trichromacy results in reduced ability to distinguish between reds and greens, though the effect is generally less severe than in protanopia. People with protanomaly can still perceive red but see it as less vivid and somewhat shifted toward green.
Deuteranomaly
(Green-Weak)Prevalence: ~2.7% of the population
Deuteranomaly is the most common form of color vision deficiency, affecting approximately 5% of men worldwide. It is a type of anomalous trichromacy in which the medium-wavelength (M) cones are present but have a shifted spectral sensitivity, peaking closer to the long-wavelength range. This reduces the ability to distinguish between greens, reds, and yellows, though most people with deuteranomaly retain functional color vision and may not even realize they perceive colors differently.
Blue-Yellow Color Blindness
Tritanopia
(Blue-Yellow Blind)Prevalence: ~0.003% of the population
Tritanopia is a rare form of color blindness in which the short-wavelength (S) cones, responsible for perceiving blue light, are completely absent or nonfunctional. Unlike red-green color blindness, tritanopia affects blue-yellow discrimination and is inherited on an autosomal chromosome, meaning it occurs at equal rates in men and women.
Tritanomaly
(Blue-Weak)Prevalence: ~0.001% of the population
Tritanomaly is an extremely rare form of color vision deficiency in which the short-wavelength (S) cones are present but have altered spectral sensitivity. This anomalous trichromacy reduces the ability to distinguish between blue and green, and between yellow and red, though to a lesser degree than tritanopia. Because it is linked to an autosomal gene, tritanomaly affects men and women at equal rates.
Types of Color Blindness FAQ
What are the main types of color blindness?
The main types are red-green color blindness, blue-yellow color blindness, and complete color blindness. Red-green is the most common group and includes protan and deutan deficiencies. Blue-yellow includes tritan deficiencies. Complete color blindness is rare and is often called achromatopsia.
What is the most common type of color blindness?
Red-green color blindness is the most common type. It can involve reduced or missing red-sensitive cones, reduced or missing green-sensitive cones, or shifted cone sensitivity that makes reds and greens difficult to distinguish.
What is the difference between protanopia and deuteranopia?
Protanopia affects red-sensitive cone function, while deuteranopia affects green-sensitive cone function. Both are red-green color vision deficiencies, but protanopia often makes reds appear darker while deuteranopia usually preserves brightness more normally.
How do I know which type of color blindness I have?
An online color vision test can screen for common patterns, but it is not a medical diagnosis. A professional eye exam can use standardized color vision tests to identify the type and severity more accurately.
Can color blindness appear later in life?
Yes. Many cases are inherited from birth, but color vision deficiency can also be acquired from eye disease, optic nerve problems, brain injury, medication effects, or other health conditions. New or changing color vision symptoms should be evaluated by an eye care professional.
Professional diagnosis note
This guide explains common color vision deficiency types for education and screening. For medical guidance, see the National Eye Institute guide to color vision deficiency types or ask an optometrist or ophthalmologist for standardized testing.
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