Types of Color Blindness

Color blindness, or color vision deficiency (CVD), comes in several forms, each affecting how you perceive different colors. Learn about the main types, their causes, prevalence, and how they affect daily life.

Medically Reviewed Content

This article has been reviewed by Dr. Sarah Mitchell, OD, a board-certified optometrist with over 15 years of experience in color vision disorders. Last updated: December 2024.

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Protanopia (Red) Deuteranopia (Green) Tritanopia (Blue) Achromatopsia Comparison Chart

Understanding Color Vision

Before exploring the types of color blindness, it's important to understand how normal color vision works. The human eye contains three types of cone cells in the retina, each sensitive to different wavelengths of light:

🔴

L-Cones (Long)

Sensitive to long wavelengths, perceiving red-orange colors (560-580nm peak)

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M-Cones (Medium)

Sensitive to medium wavelengths, perceiving green-yellow colors (530-540nm peak)

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S-Cones (Short)

Sensitive to short wavelengths, perceiving blue-violet colors (420-440nm peak)

Color blindness occurs when one or more of these cone types are absent, reduced in number, or function abnormally. The type of color blindness depends on which cones are affected.

Red-Green Color Blindness

Red-green color blindness is the most common form, affecting approximately 8% of males and 0.5% of females of Northern European descent. It includes four subtypes: protanopia, protanomaly, deuteranopia, and deuteranomaly.

How colors appear with Protanopia
Red → Dark
Green → Yellow

Protanopia

Complete Red Blindness

Protanopia is caused by the complete absence of red-sensitive (L-cone) photoreceptors in the retina. People with protanopia cannot perceive red light, and red colors appear very dark, almost black. This is sometimes called "red-dichromacy."

1%
of Males
0.01%
of Females
X-Linked
Inheritance

Colors Affected

  • Red appears very dark (brown/black)
  • Orange looks yellow/green
  • Difficulty distinguishing red from green, brown, and sometimes purple
  • Traffic lights may appear as a single yellow light

Daily Life Impact

People with protanopia may have difficulty with traffic signals, ripeness of fruits, color-coded information, and certain careers requiring accurate color perception.

How colors appear with Protanomaly

Protanomaly

Reduced Red Sensitivity (Mild)

Protanomaly is a milder form of red-green color blindness where red-sensitive cones are present but don't function normally. They have reduced sensitivity to red light, causing red, orange, and yellow to appear shifted toward green.

1.3%
of Males
0.02%
of Females
Anomalous
Trichromacy

Key Characteristics

  • Red appears less bright and more muted
  • Can still see red, but with reduced intensity
  • Less severe impact on daily activities than protanopia
  • May not be aware of the condition without testing
How colors appear with Deuteranopia
Green → Yellow
Red → Brown

Deuteranopia

Complete Green Blindness

Deuteranopia is caused by the complete absence of green-sensitive (M-cone) photoreceptors. This is the most common form of complete color blindness. People with deuteranopia confuse similar colors in the green-yellow-red portion of the spectrum.

1.2%
of Males
0.01%
of Females
X-Linked
Inheritance

Colors Affected

  • Green appears brownish or tan
  • Red, orange, yellow, and green may all appear similar
  • Blue and purple are relatively unaffected
  • Grass and trees may appear yellow or brown

Comparison with Protanopia

While both deuteranopia and protanopia affect red-green discrimination, the key difference is that red doesn't appear as dark in deuteranopia as it does in protanopia.

How colors appear with Deuteranomaly

Deuteranomaly

Reduced Green Sensitivity (Most Common)

Deuteranomaly is the most common type of color blindness, affecting approximately 5% of males. The green-sensitive cones are present but have abnormal spectral sensitivity, shifted toward red. Most affected individuals can still see green but with reduced sensitivity.

5%
of Males
0.35%
of Females
Most
Common Type

Key Characteristics

  • Green appears more red/orange than it actually is
  • Difficulty distinguishing between green, yellow, and red
  • Severity varies from very mild to significant
  • Many people are unaware they have it until tested

Blue-Yellow Color Blindness

Blue-yellow color blindness is much rarer than red-green color blindness and affects males and females equally because it is not carried on the X chromosome.

How colors appear with Tritanopia
Blue → Teal
Yellow → Pink

Tritanopia

Complete Blue Blindness (Rare)

Tritanopia is caused by the complete absence of blue-sensitive (S-cone) photoreceptors. It is extremely rare, affecting less than 0.01% of the population. Unlike red-green color blindness, it is usually acquired rather than inherited.

<0.01%
of Population
Equal
Male/Female
Often
Acquired

Colors Affected

  • Blue appears green or teal
  • Yellow appears pink, light gray, or violet
  • Purple may appear red
  • Sky may appear greenish

Causes of Acquired Tritanopia

While rare as an inherited condition, tritanopia can be acquired due to:

  • Age-related eye changes (yellowing of the lens)
  • Certain medications (e.g., some antibiotics)
  • Diseases affecting the retina or optic nerve
  • Head injuries
How colors appear with Tritanomaly

Tritanomaly

Reduced Blue Sensitivity

Tritanomaly is the milder form of blue-yellow color blindness where blue-sensitive cones are present but have reduced function. It causes difficulty distinguishing blue from green and yellow from violet.

~0.01%
of Population
Equal
Male/Female
Very
Rare

Key Characteristics

  • Blue appears greener than it actually is
  • Difficulty with blue-green and yellow-violet distinctions
  • Less severe than tritanopia
  • May go unnoticed without specific testing

Complete Color Blindness

Vision with Achromatopsia (no color)

Achromatopsia (Monochromacy)

Complete Color Blindness

Achromatopsia is an extremely rare condition where individuals see no color at all—only shades of gray. This occurs when none of the cone cells function properly, and vision relies entirely on rod cells.

1:30,000
Prevalence
Genetic
Autosomal
Severe
Impact

Associated Symptoms

Achromatopsia typically includes additional visual symptoms:

  • Photophobia: Extreme sensitivity to light
  • Reduced visual acuity: Usually 20/200 or worse
  • Nystagmus: Involuntary eye movement
  • Impaired day vision: Due to cone cell dysfunction

Treatment & Research

While there is no cure, red-tinted glasses can help reduce light sensitivity. Gene therapy trials are showing promising results for treating some forms of achromatopsia.

Color Blindness Comparison Chart

Quick reference guide comparing the main types of color vision deficiency.

Type Affected Cone Colors Confused Prevalence (Male) Inheritance
Protanopia Red (L-cone) - Absent Red-Green, Red appears dark 1% X-Linked
Protanomaly Red (L-cone) - Abnormal Red-Green, reduced red 1.3% X-Linked
Deuteranopia Green (M-cone) - Absent Red-Green 1.2% X-Linked
Deuteranomaly Green (M-cone) - Abnormal Red-Green 5% X-Linked
Tritanopia Blue (S-cone) - Absent Blue-Yellow <0.01% Autosomal
Tritanomaly Blue (S-cone) - Abnormal Blue-Yellow ~0.01% Autosomal
Achromatopsia All Cones All colors (grayscale only) ~0.003% Autosomal

Test Your Color Vision

Take our free Ishihara color blind test to screen for red-green color vision deficiency. Get instant results in just 2 minutes.

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Medical References & Sources

  • Neitz, J., & Neitz, M. "The genetics of normal and defective color vision." Vision Research, 51(7), 633-651, 2011.
  • Sharpe, L.T., et al. "Opsin genes, cone photopigments, color vision, and color blindness." Color Vision: From Genes to Perception, Cambridge University Press, 1999.
  • National Eye Institute. "Color Blindness." NIH, 2023. nei.nih.gov
  • Simunovic, M.P. "Colour vision deficiency." Eye, 24(5), 747-755, 2010.
  • Birch, J. "Worldwide prevalence of red-green color deficiency." Journal of the Optical Society of America A, 29(3), 313-320, 2012.