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Color Blindness: How Do They See the World?

Written by Andrew Le, MD

UpdatedFebruary 22, 2024

Color blindness is a common condition that affects how people perceive color. An estimated 1 in 12 men and 1 in 200 women have some form of color blindness. While there is no cure, most people with the condition adapt and lead normal lives.

This article explores what color blindness is, what causes it, the different types, how it is diagnosed, and most importantly - how people see the world differently.

🔑 Key Takeaways

  • Color blindness is caused by issues with cone cells in the retina, resulting in an inability to distinguish between certain colors. It is usually genetic but can also develop later in life due to medical conditions or environmental factors.
  • The most common type is red-green color deficiency, where people have trouble differentiating between reds, greens, browns, and oranges.
  • Blue-yellow color blindness is rarer, occurring in 1 in 10,000 people, and makes it hard to tell blues from yellows or related shades like violet, purple, and pink.
  • Complete color blindness or monochromacy, where people only see greyscale, is rare - impacting 1 in 30,000. It also comes with light sensitivity and vision problems.
  • Color blindness is diagnosed through visual tests like the Ishihara assessment, which has colored dot images that reveal a person's ability to detect specific colors and shapes.
  • Instead of vivid hues, people with color deficiencies see a more muted, distorted color palette where problematic pairings like red/green or pink/orange appear very similar.
  • While coping strategies help overcome obstacles, certain high-risk occupations require normal color vision for safety and accuracy. But most color-blind people adapt well and have normal lives.
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What is Color Blindness?

Color blindness occurs when there is an issue with the retina's cone cells, which detect color. Three types of cone cells - red cones, green cones, and blue cones - identify the various wavelengths of light and transmit this data to the brain, which then processes it into the diverse color palette that most of us see.

When one or more of these cone cells malfunctions due to genetic factors, physical or chemical damage, or certain medical conditions and medications, the brain does not receive the complete color information. This results in an inability to distinguish between certain shades as accurately as those with normal color vision.

The condition is also referred to as color vision deficiency or color deficiency. It tends to affect both eyes equally and remains constant throughout life. For most people with color blindness, the symptoms are often subtle enough that they remain unaware of their condition until tested. Parents may notice issues when their child is learning colors.

Source: Cleveland Clinic

What Causes Color Blindness?

The leading cause of color blindness is due to genetic factors - mutations in the genes responsible for producing cone cells. These genetic conditions usually occur from birth and run in families. The common red-green color deficiencies are X-linked recessive disorders, making them much more prevalent in men than women.

Besides congenital causes, color blindness can also develop later in life due to:

  • Diseases affecting the eyes, optic nerve, or brain, such as diabetes, MS, Alzheimer's, glaucoma, and macular degeneration
  • Physical or chemical damage due to trauma, excessive light exposure, or toxicity
  • Certain drugs and medications like Plaquenil used for arthritis
  • Exposure to toxic substances through work hazards or environmental damage

In many cases, the exact cause may be unknown. Acquired color blindness tends to progress gradually and affects each eye differently. Symptoms also worsen over time compared to lifelong color deficiencies, which remain constant. Treatments target the underlying condition when possible.

Types of Color Blindness

There are various types of color blindness depending on which cone cells are impacted. The three main categories include:

1. Red-Green Color Deficiency

This is the most common form, making up 99% of all color blindness cases. Red and green are confused due to issues with red and green cones. There are further sub-types based on which cones malfunction.

  • Protan deficiency: Issues with red cones, occurring in 1% of males
  • Deutan deficiency: Issues with green cones occurring in 5% of males

Those with a red-green deficiency have difficulty distinguishing between red, green, brown, and oranges. Bright greens may turn yellowish, while reds fade to browns. Different shades within these colors also become challenging to differentiate.

2. Blue-Yellow Color Deficiency

Much rarer, occurring due to missing or malfunctioning blue cones. This impacts just 1 in 10,000 people. Blues and yellows are confused. Understanding colors like violet, purple, and pink can also be impacted. Blues fade toward greens, yellow pales to a light grey or violet tone, and it becomes hard to distinguish pinks from lavenders.

3. Complete Color Blindness

Known as monochromacy, this is when two or all three cone cells do not function, leading to an inability to perceive most or any colors at all. Instead, the person sees the world in shades of grey. Complete color blindness is rare, estimated to impact just 1 in 30,000 people. Those with monochromacy may also experience extreme light sensitivity, poor vision, and uncontrolled eye movements.

There are also different levels of severity, ranging from mild to strong color deficiencies. The stronger the deficiency, the more colors become hard to differentiate. Mild color blindness may only cause difficulties in low light.

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How is Color Blindness Diagnosed?

Color blindness is diagnosed through simple vision tests administered by an optometrist or ophthalmologist. The most widely used assessment is known as the Ishihara test.

The Ishihara test consists of images of colored dots with embedded numbers or shapes. These shapes are only visible to those with normal color vision. Based on a person’s ability to identify the shape accurately, the type and severity of color blindness can be determined.

Additional assessments may be conducted to confirm the diagnosis and guide appropriate accommodations, especially for school-aged children who rely on color cues for learning. Testing children by age 4 before they begin formal education is recommended.

How Do People With Color Blindness See the World?

Color blindness does not affect visual clarity or acuity. But it does alter color perception and the vibrancy of the world around. Following are key differences in the visual experiences of those with common color deficiencies:

1. Muted and distorted color

Unlike the vivid colors most see, the color blind encounter a more faded world where certain hues shift toward others. The mixing of colors makes them seem duller and less bright overall.

For those with red deficiencies, reds fade to dark browns, and greens acquire a red/brown tinge. Bright greens turn yellowish. Oranges and yellows can shift toward pinks.

With blue deficiencies, blues fade toward green, yellow pales to a light grey or takes on a violet tone, while pinks and purples may merge to similar shades.

Just as audio pitch helps identify sounds, since color has a wavelength, specific colors have a “color pitch”. Color blindness jumbles up the “pitches,” making different colors appear as the same or similar shade.

2. Difficulty with shades and telltale color pairings

Since certain hues shift toward others, the most difficult colors are red/green, blue/purple, blue/yellow, pink/orange, and dark red/black. People with color deficiencies also struggle to differentiate between intensities like crimson vs red or teal from light green. Shades and palettes are harder to distinguish.

Simple tasks like choosing clothing, reading charts, mixing paints, and plant identification become challenging due to the inability to discern small variations in problematic hues. Many develop workarounds to overcome daily obstacles.

3. Challenges related to specific uses of color

Traffic light colors, warning signs and signals, color coding systems, and even the use of color in art can prove troublesome. Color-based learning materials also need adjustments for colorblind students. Names of colors take on heightened meaning when appearance becomes confusing.

While colors appear faded or similar, most people with the condition develop coping strategies over time. But certain occupations, like electricians, pilots, designers, scientists, and more, do require normal color vision for safety and task accuracy. Testing is mandatory for these fields.

Final Words

Color blindness does not equate to colorlessness. It means a less vibrant, more restricted view of the visual light spectrum surrounding us all. With an understanding of their condition and appropriate support where needed, the color blind adapt well and lead perfectly normal lives.

The world they view retains variation in shade and tone. But it differs from what is considered the “standard perspective.” However, the notion of the standard itself allows room to encompass alternate yet equally valid experiences just as there are individual differences in opinions, personalities, and talents – so too in how we each perceive this brightly colored world of ours.

FAQs on Color Blindness

Are animals color blind?

Some animals are color blind, while others see limited color compared to human vision. Dogs see primarily yellows and blues, for instance. Cats perceive color similarly to people with red-green color blindness. Birds, fish, reptiles, and insects vary widely in color vision.

Can color blindness be corrected?

There is currently no cure for congenital color blindness. Special glasses and contacts that enhance contrast can compensate mildly in some cases. Research into gene therapy shows promise but is still being refined and tested.

Can color blindness get worse over time?

In inherited cases, the symptoms usually remain steady. But with acquired color blindness, gradual worsening of color perception is common as the underlying condition progresses with age.

Do color-blind people dream in color?

Yes, even those lacking color sight tend to have colorful dreams based on childhood memories. The brain retains the ability to perceive color in the dream state.

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