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All About Color Vision Deficiency

Reviewed by Azhar I. Salahuddin, MD · Updated July 2025

color vision deficiency

What is Color Vision Deficiency?

Color vision deficiency, or color blindness, is the inability to distinguish certain shades of colors. In highly severe cases, people can’t see the concerned colors at all, though very few people are completely color blind (who can see things only as black, white, and shades of gray).

Color blindness occurs when there is damage or loss of cones, which are the photoreceptors in the retina, making color vision possible. If the cones lack one or more light-sensitive pigments, the color perception will be deficient, making it difficult to see one or more of the three primary colors.

Types of Color Vision Deficiencies

The Red-Green Color Deficiencies

The most common color vision deficiency affects more men than women. People have difficulty distinguishing between different shades of red, green, and yellow. Either they all appear to be a similar color, appear dull, or can only be distinguished by slightly different brightness and intensity. They may even confuse red with black. Shades of purple will appear blue as you won’t be able to see the red component in them.

Deuteranopia And Deuteranomaly

This occurs when there is a loss of M-cones. It’s a less severe form of red-green color vision deficiency where you’ll have trouble differentiating between different shades of the same color in the red-yellow-green spectrum.

Protanopia And Protanomaly

Loss of L-cones leads to protanopia. You’ll confuse colors in the red-yellow-green spectrum if you suffer from this deficiency. Protanomaly is a less severe form where you won’t be able to distinguish different shades of the same color in the red-yellow-green spectrum. Those suffering from either disease are likely to see red colors as darker than normal.

Blue-yellow color vision deficiency

This deficiency is quite rare and is caused due to a deficiency of S-cones. It’s also known as Tritanomaly or Tritanopia. With this deficiency, you will have difficulty distinguishing between blue and green, with green appearing as a shade of blue. Some even see yellow as a pale shade of grey or purple.

Also Read: Role of Genetics on Your Eye Health

Color Blindness Symptoms and Signs

Common symptoms to identify color blindness include:

Also Read: What is the Visual Acuity Test?

Causes of Color Vision Deficiency

Most cases of color deficiency are genetic and are passed from the parents to the children. Apart from that, certain diseases and medical conditions may also lead to a loss of color recognition. Some include:

Other factors also include:

Also read: How Early Eye Exam Could Detect Alzheimer’s?

Color Blindness Treatment

In most cases, there is no cure, but if it’s caused due to an illness or an eye-injury, treatment may improve color vision. Color cues and other methods can help color-deficient people compensate for their inability to distinguish colors.

If you suspect colorblindness in yourself or a loved one, go to an eye doctor immediately. Give InSight Vision Center a call at 559-449-5050 or make an appointment today for a comprehensive diagnosis.

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This article is general information and isn't a substitute for an eye exam.