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Types of Color Blindness: The Basics

"Color blindness" is really an umbrella term for a group of vision differences — the underlying mechanism and severity vary quite a bit from type to type.

Normal color vision relies on three types of cone cells

The retina normally contains three types of cone cells, each most sensitive to a different wavelength of light — roughly corresponding to red, green, and blue. The brain compares the signals from all three to distinguish colors. When one or more of these cone types is missing or not working properly, some degree of color vision difference results.

Red-green color blindness: the most common type

Red-green color vision deficiency is by far the most common form, and it’s not rare among men. It splits further into reduced sensitivity to red versus reduced sensitivity to green, and people affected typically struggle to tell red and green apart, or perceive the two as looking quite similar. Exact rates vary by the population studied and tend to differ between regions.

Blue-yellow color blindness: a rarer type

Blue-yellow color vision deficiency affects the ability to distinguish blue from yellow. It’s far less common in the general population than red-green deficiency, and it can be inherited from birth or acquired later as the result of certain eye or neurological conditions.

Total color blindness: unable to distinguish any color

Achromatopsia, or total color blindness, is the rarest form — people with this condition can barely distinguish colors at all, and what they see is closer to varying shades of gray. It’s usually accompanied by other vision problems, such as light sensitivity and reduced visual acuity, and it occurs far less often than red-green deficiency.

Why color blindness is much more common in men

The genes behind the common forms of red-green color vision deficiency sit on the X chromosome and are recessive. Men have only one X chromosome, so a single copy of the gene is enough to cause the condition. Women have two X chromosomes, so they typically need both copies affected — which is why red-green color vision deficiency shows up far more often in men across most population studies.

Most people with color blindness don’t see in black and white

What’s casually called "color blindness" is often really milder "color weakness" — the person can still see color, just has more trouble distinguishing certain hues, especially similar ones, than someone with typical vision. That’s quite different from the popular movie trope of seeing the world in nothing but black and white.

How color blindness test charts are designed

Standard color-vision screening charts, such as pseudoisochromatic plates, hide a number or shape inside a field of colored dots. The hidden shape and the background dots differ in hue in a specific way that’s much harder for certain types of color vision deficiency to pick out. Clinics typically combine several test methods to determine the specific type and severity.

The everyday impact varies a lot from person to person

People with mild color weakness can often compensate using brightness, position, and other visual cues, so the day-to-day impact is limited. But in situations that hinge heavily on color judgment — reading traffic signals, distinguishing color-coded wiring — even a mild deficiency can create real practical difficulties, which is why some professions include a color vision test as part of a physical exam.

Frequently Asked Questions

Can color blindness be cured later in life?

Most genetically inherited forms of color blindness or color weakness currently have no medication or surgical cure. So-called "color-correcting glasses" work mainly by using tinted lenses to boost the contrast between certain colors, which can make specific colors easier for some wearers to distinguish — but they don’t change how the retina itself perceives color, and results vary from person to person.

What should someone do if they suspect they have a color vision deficiency?

If you regularly struggle to tell colors apart, or find certain color combinations especially confusing, it’s worth getting a proper color vision test at a qualified eye clinic rather than relying on self-testing with pictures found online. This page is for general information only and isn’t a diagnostic tool.