Every minute, about 12 people around the world are born with color vision deficiency. In this article, Ability Central addresses the symptoms and early signs of the diagnosis. We will address the following:
What are the early symptoms of colorblindness?
What are the symptoms of red-green colorblindness?
What are the symptoms of blue-yellow colorblindness?
What are the symptoms of full-color blindness?
Do cataracts cause color vision deficiency?
Does retinal detachment cause color blindness?
What are the different kinds of color vision tests?
What is an Ishihara test?
What is an EnChroma color blind test?
Where can I get more information about color vision deficiency?
What are the early symptoms of colorblindness?
People who are colorblind tend to be born with the condition, which means that until they receive a diagnosis, they go through life thinking everyone sees colors the same way they do. Because of this, it’s easy for color blindness to go unnoticed for a long time. In fact, color blindness symptoms are often so mild that a person doesn’t know they’re colorblind!
Sometimes, however, color vision deficiencies can be severe enough to cause confusion and frustration. Parents and teachers are often the first to see the earliest signs of color blindness, especially when a child reaches school age.
Early symptoms of colorblindness may appear in childhood. They include:
Trouble seeing colors
Difficulty seeing the brightness of colors
Inability to tell the difference between shades of colors
An outside observer, like a parent or teacher, might also notice things like:
Over-sensitivity to light
Relying on smell more than sight (for example, instead of poking and prodding a suspicious new food, insisting on smelling it)
Difficulty focusing on coloring pages or worksheets
Coloring things “wrong,” like blue grass or a purple sun
Selecting mismatched clothing, like different-colored socks or shoes
What are the signs of red-green colorblindness?
Red-green color blindness is the most common form of color deficiency. With red-green colorblindness, people can’t see shades of red and green like people with normal color vision do.
Someone with red-green color blindness might confuse orange and red, see blue and yellow tones in colors like green, or have difficulty differentiating between pale shades.
For example, a person who is red-green color blind might see grass, which people with full color vision see as green, in shades of blue. Alternatively, they might see a red stop sign as brown or muddy green.
There are five types of red-green colorblindness:
Protanopia. Missing L-cones make it impossible to perceive red light. Colors appear in shades of blue and gold. It's easy to confuse red with black and dark brown with other dark shades, like dark green, orange, or red.
Deuteranopia. Missing M-cones make it impossible to perceive green light. Colors appear in blues and golds. Reds and greens are easy to confuse, as are yellows and bright greens.
Protanomaly. All three cones exist, but L-cones aren't as sensitive to red light. Red appears dark gray and colors that contain red (pink, purple, orange, etc.) are less bright.
Deuteranomaly. All three cones exist, but M-cones aren't as sensitive to green light. Colors are mostly muted shades of blue and yellow.
Blue cone monochromacy (BCM). All three cones exist, but L-cones and M-cones are less sensitive than they should be. BCM is a genetic condition that almost exclusively affects males. In addition to low color vision, people with BCM experience light sensitivity, nearsightedness, low vision, and nystagmus (uncontrollable eye movements).
Some people live years without knowing they have red-green color blindness because what they see looks “normal” to them. Often, people don’t realize they are color blind until someone points it out, or until they take a routine eye test.
What are the signs of blue-yellow colorblindness?
People with blue-yellow color blindness have either no blue cone cells or deficient blue cone cells. Blue-yellow color blindness is rare, affecting only ~1 in 10,000 people. There are two main kinds of blue-yellow colorblindness: tritanomaly and tritanopia.
Tritanomaly makes it hard to distinguish between colors that contain blue or yellow tones, like blue and green, yellow and pink, or purple and red. For example, someone with tritanomaly may not be able to differentiate between the red, yellow, and green lights on a stop light.
Tritanopia is a rare form of blue-yellow color blindness. It makes it difficult to see any color that contains blue or yellow, or in other words, tell the difference between blue/green, purple/red, or pink/yellow. For example, someone with tritanopia may not be able to tell which parts of a map are water and which are land, if the only indication is green for land and blue for water.
What are the signs of full-color blindness?
Full-color blindness means the person cannot see color at all. Everything appears in grayscale. Full-color blindness is also called:
Complete-color vision deficiency
Monochromacy
Achromatopsia
In this condition, two or all three types of cones are absent, which makes the world appear in black and white.
Because monochromatic vision relies on contrast, people with achromatopsia are often immensely sensitive to light, which can turn everyday tasks into difficult or painful chores. For that reason, those who experience this extremely rare color vision impairment often wear dark glasses to help protect their eyes, even indoors.
To understand more about the cones that cause colorblindness, see 7 Fast Facts to Know About Color Blindness.
Do cataracts cause color vision deficiency?
Cataracts make the eye’s natural lens seem clouded. While this may dull color vision, it is not the same as color blindness. Once the cataract is treated, color vision should be restored.
Does retinal detachment cause color blindness?
Retinal detachment causes the rapid loss of blue cones. This may lead to blue-yellow color confusion in some people.
For more information on blue cones, see 7 Fast Facts to Know About Color Blindness.
What are the kinds of color vision tests?
Your eye care professional can conduct several tests to detect color vision deficiency. They include:
Color plate test (Ishihara test): The eye doctor will ask you to look at a circle with different colored dots. Inside the circle is a shape. You may have a color vision deficiency if you can’t see the shape. See “What is an Ishihara test?” below for a link to an online example.
Anomaloscope test: This test checks if you can match the brightness of two lights.
Hue test: You arrange blocks of color from red to purple.
Ability Central offers a searchable database of nonprofit service providers if you have questions about any of these tests.
What is an Ishihara test?
The Ishihara test, the most commonly used color vision test, detects red-green color deficiencies. It was named after its designer, Shinobu Ishihara.
The Ishihara test uses “plates” made up of multi-colored circles: someone with normal color vision will immediately be able to see a number or squiggly line on the plate, while someone with color blindness will see a different number, or nothing at all.
A free sample test can be found online.
What is an EnChroma color blind test?
The EnChroma Colour Blind Test is a proprietary test designed to determine a person’s type and level of color blindness. It is based on the Ishihara “hidden digit” test method. EnChroma uses the results of this test to recommend various color-corrective glasses designed for the different types of color vision deficiency.
You can find this test online.
Where can I get more information about color vision deficiency?
The best way to find out if you’re color blind is to schedule an eye test. These tests can be administered by opticians, optometrists, or some schools.
Many nonprofit organizations offer free or low-cost services like color blindness testing for people with vision impairments. Check out Ability Central’s [Service Locator tool to find an organization near you.
In the meantime, to learn more about color blindness in children and adults, see:
To learn more about other vision conditions linked to color blindness, see:
