Whether you live with the condition or not, color blindness can be a confusing topic. Simply put, color blindness is an eye condition that stems from faulty cone cells in the retina, making it difficult to differentiate between colors. While there is no cure for the condition, special contact lenses and glasses can be helpful.
There are many different names for color blindness, including:
- Dyschromatopsia (dichromic)
- Defective color vision
- CVD (color vision deficiency)
- Poor color vision
You get the picture. But what causes color blindness? Are there different types of color blindness? Can it be treated? This article answers these and many other questions related to color blindness.
HOW DO WE SEE COLORS?
To get a clearer picture of what color blindness is, let’s start by looking at how we see colors.
The American Academy Of Ophthalmology points out that objects don’t possess colorsbut rather reflect wavelengths of light. Our eyes respond to high and low light frequencies similar to how our ears hear sounds as pitch.
For example, blue colors have short wavelengths, and red frequencies have long wavelengths. We all see colors in a continuum, but the specific colors we see in that continuum depend on the function of our photoreceptors.
Photoreceptors are special cells in the eye, responsible for converting light signals and telling the brain what color we are looking at.
WHAT IS COLOR BLINDNESS?
Color blindness is a person or animal’s inability or reduced ability to distinguish between colors. When someone is color blind, they have problems distinguishing between shades like green, red, or yellow.
According to the American Academy Of Ophthalmology, color blindness usually occurs between greens and reds, and sometimes blues.
WHAT ARE THE TYPES OF COLOR BLINDNESS?
According to the National Eye Institute, there are three different ways of being color blind:
FOUR TYPES OF RED/GREEN COLOR BLINDNESS
- Deuteranomaly – Green looks more like red.
- Protanomaly – Red looks more like green.
- Protanopia & deuteranopia – Complete failure to distinguish between red and green
TWO TYPES OF BLUE-YELLOW COLOR BLINDNESS
- Protanomaly – Difficulty distinguishing green and blue, yellow/red
- Protanopia – Blue and green, purple and red, yellow and pink. The colors look less bright.
TWO TYPES OF COMPLETE COLOR BLINDNESS (ALSO CALLED MONOCHROMACY)
- Rod Monochromacy – No detectable cone function. Rod monochromats only see shades of gray.
- Cone Monochromacy – This is a situation where there is only one functioning type of cone. Cone monochromats can see in normal daylight but have trouble seeing hues.
HOW COMMON IS COLOR BLINDNESS?
Color blindness affects around 1 in 12 males and 1 in 200 females.
According to MedlinePlus, blue-yellow color vision is a more rare condition that only affects around 1 in 10,000 people globally. Another interesting fact about blue-yellow color vision is that it affects males and females equally.
HOW IS COLOR BLINDNESS DIAGNOSED?
Color blindness diagnosis happens through a comprehensive eye examination. The test procedure consists of the doctor showing the patient a series of dotted pictures called pseudoisochromatic plates.
The dots in each picture have a number in the center, composed of different colors. A person with full-color vision can easily see the number in the center of each picture and will most typically blow through the test without missing a beat.
On the other hand, a color blind person will struggle to see some of the colors, and the severely color blind fail to see anything but just dots in the photo.
The score yielded by this comprehensive eye examination determines the severity of color blindness.
IS COLOR BLINDNESS HEREDITARY?
The red-green color blind trait is most commonly passed through genes from mother to son through the X chromosome called X-linked recessive pattern.
Women don’t easily inherit red-green color blindness because they have two X chromosomes (men have an X and a Y). The gene mutation would have to occur on both copies of the chromosome for the disorder to occur.
The blue-yellow condition is not sex-specific and is passed from an affected parent in an autosomal dominant pattern (the manner in which genetic traits are passed from a parent to the child).
WHAT ARE THE CAUSES OF COLOR BLINDNESS?
The eye’s retina is composed of two different types of light receptor cells called rods and cones. These are what transmit visual signals from our eyes to our brains.
The three types of cone cells contain their specific pigment. Each pigment transmits different signals to the brain that allow it to process different colors. Rods provide low-light vision, and cones provide bright light vision.
Color blindness is most commonly heredity, meaning it runs in the family. However, the National Eye Institute states that different diseases like glaucoma (damage to the eye’s optic nerve due to pressure build-up caused by fluids in the eye) and macular degeneration can also cause the cones in the eyes to lose their light-detecting ability.
NON HEREDITARY CAUSES
Acquiring color blindness isn’t something doctors see every day, but it still happens. Here are a few non-genetic causes identified by the American Optometric Association.
Exposure to chemicals: Chemicals like styrene and fertilizers can cause color vision defects in humans.
Medications: Medication for high blood pressure, infections, nervous disorders, heart problems, and psychological problems can cause CVD.
Cataracts: A cataract is a vision-inhibiting cloud that covers the lens of the eye.
Optic nerve damage: Damage to the nerve that connects the eye to the brain.
Brain damage: When the part of the brain that processes colors fails.
Aging: Parts of the eye, brain, and nervous system failing to produce color vision over time.
Illness: Some sicknesses can also cause color blindness:
- Parkinson disease
- Multiple sclerosis
- Macular degeneration
- Stroke in the occipital lobe
- Diabetic retinopathy
- Diseases affecting the eye lens or retina
WHAT ARE THE SIGNS AND SYMPTOMS OF COLOR BLINDNESS?
Although some signs of color blindness are obvious, it’s pretty common for someone to be unaware of their color deficiency. Consequently, ColorBlindAwareness.org reports that some children don’t find out they are color blind until later on in life.
The National Eye Institute points out that some children might even try to hide it.
Here are the two main signs that you may be color blind:
Difficulty distinguishing between colors in everyday life
A child might discover they are color blind when they color the ocean purple instead of blue at school. Drivers might have difficulty distinguishing between the red and green stoplights.
Colors aren’t as bright as they used to be
In a non-hereditary case of color blindness, the patient might notice a difference in the brightness of their color vision.
HOW IS COLOR BLINDNESS TREATED?
Hereditary color blindness is unfortunately untreatable because the color blind person doesn’t have the functioning light-detecting rods in their biological makeup.
Color vision defects that happen because of injury or illness are sometimes treated with solutions like specially tinted eyeglasses called EnChroma glasses or contact lenses to help the patient more easily distinguish between colors.
Although color vision defects are presently untreatable, people who are color blind learn how to adapt to their circumstances to help them navigate the everyday world.
For example, a red-green color blind person knows that the red stoplight is on the top, and the greenstoplight is on the bottom. The only problem might arise when the person travels to a place where the stoplights go horizontally.
A color blind person might organize their clothes and personal possessions with the help of a family member to ensure they know what color to choose.
DOES COLOR BLINDNESS CAUSE OTHER HEALTH PROBLEMS?
The common red-green color blindness isn’t responsible for any further vision loss or a worsening condition of vision.
Even though color blindness doesn’t cause other health problems, people who are color blind should consult a doctor immediately for an eye examination if they notice their vision worsens in any way.
CAN COLOR BLINDNESS BE PREVENTED?
There is no way to prevent hereditary color blindness. So, unfortunately, some people have to live with the fact that they don’t see colors as vividly as the majority.
Non-hereditary color blindness can be prevented by regular eye exams, living a healthy lifestyle, and avoiding toxic chemicals.
CAN COLOR BLINDNESS AFFECT A PERSON’S CAREER CHOICE?
Yes, there are plenty of careers that require the ability to distinguish color. For example, an electrician dealing with different colored wires might find it impossible to safely perform their daily tasks without the ability to see color.
Occupations like flying airplanes will require a test for color blindness before certification. Even practical day jobs like firefighting, military service, and law enforcement can restrict colorblind people from occupying some positions.
Other notable occupations that color blind people can’t do include:
- Meat inspectors
- Bus drivers
- Diamond appraisers
- Web designers
WHAT ARE THE ONGOING STUDIES ON COLOR BLINDNESS?
Is it possible that color blindness has a cure? It’s likely but remains unproven on a human patient. Scientists at the University of Washington have invented gene therapy that helps restore gene codes for a faulty light-sensitive pigment through a single injection.
This treatment has been tested on animals with blue and green wavelength cell sensitivity. After a few months, the animals gain the ability to distinguish a red dot embedded image inside of a field of dots that vary in color.
Scientists are hoping to move to human trials soon.