What Do Color Blind People See?

Color-blind people see differently depending on what kind of color blindness they have. For example, some people may not be able to tell certain colors from others. Colors can also appear muted. In rarer cases, someone who is color blind may not see color at all.

This article covers the various types of color blindness to help you better understand what color-blind people see and why it can vary. It also talks about how color-blind people can adapt to make living with their vision difference easier.

How Color Blind People See Color

Color blindness doesn't always mean a person only sees in shades of gray. This type of color blindness is considered the most severe, but it's uncommon. Most people with color blindness simply see a narrower range of color than someone with full-color vision.

What this means in terms of their vision differs. People with color blindness may:

• Confuse certain colors: For example, the color red may look the same as the color green.
• Have difficulty in certain light: Some people with mild color vision deficiency can see colors normally in good light, but not in dim light.
• Not see certain or any colors, no matter the light

Color blindness usually affects both eyes equally and remains stable throughout life.

How Types of Color Blindness Affect What Someone Sees

There are several different types of color blindness. Each type of color blindness affects the way a person sees color in a different way.  People with red-green color blindness, for example, have more color vision than those who have blue-yellow or complete color blindness.

Red-green and blue-yellow color blindness disrupts color perception, but does not affect visual acuity.

Red-Green Color Blindness

Inability to tell the difference between red and green

The most common type of color blindness is red-green color blindness. It occurs in about one in 12 males and one in 200 females among people of Northern European ancestry.

There are four types of red-green color blindness:

• Deuteranomaly causes green colors to look red.
• Protanomaly causes red colors to look green.
• Protanopia is when you cannot see red light. People who have protanopia color blindness are red-blind and see more green than red. They find it hard to tell the difference between red-related colors.

• Deuteranopia is when you cannot see green light. People who have deuteranopia see more red than green. They have difficulty telling the difference between green-related colors.

Blue-Yellow Color Blindness

Difficulty telling the difference between blue and green, yellow and red, and/or dark blue and black

Blue-yellow color blindness, also called tritan defects, is a less common type of color blindness. It affects 1 in 10,000 people worldwide. Men and women are equally affected.

There are two types of blue-yellow color blindness:

• Tritanomaly makes it difficult to tell the difference between blue and green, and between yellow and red.
• Tritanopia causes someone to be "blue-blind," meaning they have difficulty telling the difference between blue-related colors. This prevents them from telling the difference between blue and green, purple and red, and yellow and pink. It makes colors look less bright, too.

Blue Cone Monochromacy

Inability to see any color at all

Blue monochromacy is uncommon and a more severe form of color blindness. It affects about one in 100,000 people worldwide and occurs at a higher rate in males than females.

Instead of seeing color, people with this type of color blindness view the world in shades of gray. They also have additional vision problems, such as:

• Increased light sensitivity (photophobia)
• Involuntary eye movements (nystagmus)
• Nearsightedness (myopia)

Blue cone monochromacy is sometimes considered a form of achromatopsia (a partial or total lack of color vision with other vision problems).

What Causes Color Blindness?

The retina contains three types of color cone cells: red, green, and blue. Each cone contains a specific pigment called an opsin. These pigments are most sensitive to particular wavelengths of light.

The brain combines input from all three types of cones to produce normal color vision. When one or all color cone cells are not present, mild or severe color blindness takes place.

Mild color blindness happens when all three cone cells are present but one cone cell does not work right.

Severe color blindness occurs when all three cone cells are absent.

Color Blindness Genes

Mutations in the genes that provide instructions for making the three opsin pigments in cones cause different forms of color blindness.

• Cones with opsin made from the OPN1LW gene are called long-wavelength-sensitive or L cones.
• Cones with opsin made from the OPN1MW gene are called middle-wavelength-sensitive or M cones.
• Cones with opsin made from the OPN1SW gene are called short-wavelength-sensitive or S cones.

Genetic changes involving the OPN1LW or OPN1MW gene cause red-green color blindness in different ways:

• Deuteranomaly happens when the M cones of the eye are present but non-functional.
  
• Protanomaly occurs when the L cones of the eye are present but non-functional.
• Protanopia occurs when the L cones of the eye are not present.
• Deuteranopia happens when M cones of the eye are not present.

Blue-yellow color blindness is caused by defects in the OPN1SW gene. People with this type of color blindness either have S cones that are non-functional or S cones that are destroyed before they're supposed to be.

Blue cone monochromacy happens when changes in the OPN1LW and OPN1MW genes cause both the L and M cones to become non-functional.

Can You Become Color Blind?

People are usually born with color blindness, but color blindness can also happen later in life if your eyes or the part of your brain that helps you see color is damaged. This is called acquired color vision deficiency and can be caused by:

• Eye diseases, like glaucoma or macular degeneration
• Brain and nervous system diseases, like Alzheimer’s or multiple sclerosis
• Some medicines, like Plaquenil (hydroxychloroquine)
• Eye or brain injuries
• Normal aging, especially with cataracts, cloudy areas on the eye

Adjusting to Being Color Blind

Living with color blindness can be hard. People with color blindness have trouble performing daily tasks that require them to tell the difference between colors. Examples of some daily activities that affect color blind people are: 

• Driving
• Putting together a coordinated outfit
• Preparing safe meals
• Using gadgets

Nevertheless, it is possible to live normally with color blindness by changing some daily routines, including:

• Memorizing patterns: Activities like driving can be difficult, especially when you can't see the colors in a stoplight. Paying attention to the position of the lights helps you know what to do.
• Altering the lighting at your home or office: Working in a dark or poorly lit space makes it harder to see with color blindness. Daylight bulbs can brighten your environment.
• Labeling your clothes: A labeling system, such as writing the color of the garment on the tag, can help you coordinate your outfits. 
• Using your other four senses: Utilize your senses of smell, touch, taste, and hearing. For example, choose fresh fruits from the grocery store by using touch and smell.
• Enabling the accessibility button on your devices: Modern gadgets have accessibility options that may help. Also, look for apps designed to help with color blindness.

EnChroma Glasses can help color blind people see some colors. If you have color blindness, talk to your healthcare provider about ways to manage color blindness.

Summary

Color-blind people don't always see in shades of gray. In fact, this form of color blindness is rare. Instead, most people with color blindness see a limited range of colors. They may confuse one color with another.

There are a few different types of color blindness. Red-green color blindness is the most common. People with this type have a hard time telling the difference between red and green. Blue-yellow color blindness is less common. This type makes it hard to distinguish between blue and green, yellow and red, and dark blue and black.

Blue cone monochromacy is a severe type of color blindness. People with this type don't see any color at all.