Color blindness is commonly considered primarily a male condition. Because of this, you may sometimes hear the claim that women cannot be color-blind at all. In reality, this is a myth. Women can also have color vision deficiencies, although some types are indeed much less common in women than in men.

The main reason for this difference is related to the way the genes responsible for perceiving red and green are inherited.

Why Color Blindness Is More Common in Men

Color blindness, or color vision deficiency, refers to a group of conditions in which a person has difficulty distinguishing certain colors or shades. The most common type affects the perception of red and green.

The genes responsible for producing the light-sensitive pigments needed to perceive these colors are located on the X chromosome. Therefore, the most common red-green color vision deficiencies are usually inherited in an X-linked recessive pattern.

Men have one X chromosome and one Y chromosome. If the relevant genetic variant is located on their only X chromosome, the color vision deficiency may be expressed.

Women have two X chromosomes. If the altered gene variant is present on only one of them, the other usually contains a working copy. In this case, a woman is generally a carrier but does not herself have a pronounced color vision deficiency.

This pattern of inheritance explains why red-green color blindness is much more common in men.

How Rare Is Color Blindness in Women?

Among people of Northern European ancestry, red-green color vision deficiencies occur in approximately one in 12 men and one in 200 women. However, the figures can vary considerably between different populations.

How Can a Woman Be Color-Blind?

For classic red-green color blindness to be expressed in a woman, the corresponding genetic variant usually has to be present on both X chromosomes.

For example, the mother may be a carrier of the variant, while the father may have red-green color vision deficiency. In this case, the daughter may inherit the altered X chromosome from both parents and have a color vision deficiency herself.

There is also an important inheritance pattern to consider. A man with an X-linked condition does not pass his X chromosome to his sons, because a son receives a Y chromosome from his father. Daughters, however, receive their father’s X chromosome. Therefore, a man with red-green color blindness passes the corresponding genetic variant to all of his daughters. However, carrying this variant does not necessarily mean that a daughter will be color-blind.

Not All Color Vision Deficiencies Are Linked to the X Chromosome

It is also not entirely accurate to think of color blindness only as an inherited problem involving red and green colors.

The most common red-green deficiencies are indeed linked to genes on the X chromosome, but other forms also exist.

For example, blue-yellow color vision deficiency is associated with a gene located on another chromosome. As a result, it may occur in men and women at approximately the same rate. However, this type of deficiency is much less common than red-green deficiency.

There are also very rare conditions in which a person can barely distinguish colors at all. One of them is called achromatopsia. Depending on the specific form, it may also be accompanied by reduced visual acuity and increased sensitivity to light.

In addition, problems with color perception are not always congenital. They can develop during a person’s lifetime because of eye diseases, damage to the optic nerve or certain areas of the brain, injuries, certain medications, and other causes. Age-related changes, such as cataracts, can also affect color perception.

Color Blindness Does Not Mean Seeing the World in Black and White

Another common myth is that color-blind people see the world exclusively in black and white.

In most cases, the reality is different. A person continues to see colors but may have difficulty distinguishing certain shades.

For example, with deuteranomaly, some shades of green are perceived differently. With protanomaly, certain shades of red may appear greener and less bright. In more pronounced forms, red and green become significantly more difficult to distinguish.

A complete absence of color vision does exist, but it is extremely rare.

With a mild form of color vision deficiency, a person may not even be aware of it. If the condition has been present since childhood, the person usually becomes accustomed to perceiving colors in that way and learns to navigate everyday life accordingly.

How Is Color Vision Deficiency Diagnosed?

Special tests are used to assess color vision. One of the best known is based on images made up of many colored dots. Hidden within them are numbers, letters, or other symbols that a person with a particular deficiency may not see or may perceive differently.

If necessary, an ophthalmologist can perform additional examinations to determine the specific type and severity of the deficiency.

Testing is especially relevant for children if similar conditions have occurred in the family or if the child regularly has difficulty distinguishing colors.

What Is the Bottom Line?

Women can have color vision deficiencies. The most common red-green type is usually inherited through an X-linked recessive pattern, which is why it occurs much more often in men.

At the same time, some forms of color blindness are not linked to the X chromosome, and acquired color vision deficiencies can develop in people of any sex.