Factors of Color Blindness And Its Test
A colour blind test checks if you can accurately see colours. If you cannot pass the test, you have a colour vision deficiency.
[Reading Time : 5 min | Date : 22, February 2023 | Author : Omar Setty ]
Color blindness, also called as color vision deficiency (CVD), is a condition in which you are unable to see colors in the usual way. This can happen only when some cells known as photoreceptors, or more specifically cones, are missing or not working properly in your eyes.
These cones generally allow you to see every color in the rainbow. If you are color blind, you may not see each and every color properly. Don't confuse color blindness with a type of color blindness (a condition in which you have limited or no vision): color blindness is simply a change in the way your eyes see color, check if you are color blind by doing color blindness test.
We all see a continuum (range) of colors, but which ones we see depends on how well our photoreceptors are working. Photoreceptors are cells in the eyes that respond to specific wavelengths of light.
Everyone sees colors slightly differently , and the way we see color can also change with age as we develop certain age-related eye conditions such as cataracts.
Why do we see different colors?
When we see different colors, we are actually seeing different wavelengths of light. Your eyes contain photoreceptors (cells) that process the light entering the eye to help you see color. Rods detect differences between dark and light.
Cone cells detect colors when lighting conditions are bright enough. Each wavelength corresponds to a different hue in the visible light spectrum. Red is the longest wavelength, green is medium, and blue is the shortest.
What colors of the rainbow do people with color blindness see?
In general, people with color blindness have trouble articulating what they perceive, but scientists suspect that the typical color blind person might see colors as different shades of blue and yellow. For example, what a color normal person calls purple and what a color blind person calls purple may not be the same color. Or both people look at the same color and call it different things.
A person's color vision falls into one of the following categories:
Full color vision/trichromism: If you were born with normally functioning color pigments in all three types of cones in your eyes, you are trichromatic. You would see six colors in your rainbow: red, orange, yellow, green, blue, and purple.
Color blindness/dichromatism: If you were born with missing or defective (non-functioning) cones of any of the three types in your eyes, you are a dichromat or dichromat.
The colors you see depend on which cones are missing or broken. If you're a dichromat, there are several specific types of color deficiency you may experience, including:
Red-green color deficiency
Protanopie: In this case, your long, red-responsive photoreceptors also malfunction, so you don't see red or green properly. Colors that contain red will also look different to you. Their rainbow is mostly made up of what trichromats call blue and gold.
Deuteranopie: This time, your green-responsive photoreceptors aren't working. If you are a deuteranope, your rainbow will also appear as a series of blues and golds.
Protanomalie: With this type of color deficiency, you have some red-responsive cones, but they don't work properly. Her rainbow appears muted. Red can appear dark gray, and any color that contains red can be less bright.
Deuteranomalie: In this case, green responsive cones are not working as they should. It is the most common form of color blindness. Your rainbow is most likely made up of blues, yellows, and generally muted colors.
Blue-Yellow Color Deficiency
Tritanopie:This is blue-yellow color blindness. That means you don't have blue-responsive cone cells. Your rainbow can include red, light blue, pink, and lavender.
Tritanomalie: This type of color blindness occurs when your blue-responsive cone cells function, but not as well as a fully color-sighted person. Her rainbow has greener shades of blue and there is little or no yellow.
Completely Color Blind/Monochrome: If you are a monochromat, you have very limited or no ability to see color. Your vision may be like watching a black and white TV or an old black and white movie. Your rainbow would appear in different shades of gray.
Monochromats come in two types:
Blaukegel-Monochromie: With this type of monochrome, you only have one type of cone that contains functioning photoreceptor cells. When only one type of cone is working, it is difficult to distinguish between certain colors, and most of the time you see shades of gray.
Bluecone monochromats may also have poor vision in general, sensitivity to light, nystagmus or tremors of the eyes, and nearsightedness. Blue cone monochrome is rare.
Stabmonochromie: In this condition, your retina's rod photoreceptors are functioning, but all or most of the cones are missing or malfunctioning. It is also called achromatopsia.
You see everything in shades of gray. Achromats are also likely to suffer from visual impairment, nystagmus, and sensitivity to light.
How common is color blindness?
Color blindness is uncommon, but it runs in families. This means that if other members of your family have experienced color blindness, you are more likely to have it too. Color blindness can occur in both men and women, but is much more common in men. This is because color blindness is passed through your genetic code.
Sometimes color blindness can also show up later in life. In some cases, it may have been present at birth but not noticed until later. In other cases, eye injuries or diseases can cause malfunctions in the parts of the visual system that enable color vision, including not only the photoreceptors but also the nerves and some layers of the retina.
How is color blindness inherited?
Red-green color blindness, by far the most common form, is a genetic mutation passed to children on the X chromosome. At conception, an egg cell carries an X chromosome and the sperm cell can carry either an X chromosome or a Y chromosome.
If you have an XX chromosome pair, the resulting baby will be female. If you have an XY pair of chromosomes, the baby will be male. The gene responsible for color blindness is located on the X chromosome. In other words, red-green color blindness is an X-linked recessive disorder.
If a woman inherits a normal color vision gene and a mutated gene, she will not be red-green color blind as it is a recessive trait. If she inherits two mutated color tendons, she will be red-green-blind.
Because boys only have one X chromosome, they are much more likely to inherit red-green color blindness. Boys always inherit their X chromosome from their mother. If mom is red-green color-blind or mom's father is red-green color-blind, her son will be too.
Symptoms and Causes
What causes color blindness?
Color blindness is caused by a change (mutation) in your genes. In most cases you are color blind from birth. If you're color blind, it's usually because your eyes don't contain the normally functioning cones needed for full color vision.
What are the signs and symptoms of color blindness?
You could have some form of color blindness if you have problems:
- Recognize the difference between certain colors.
- See the brightness of certain colors.
- Distinguish the difference between certain shades.
The signs and symptoms of color blindness can vary by type. If you inherited your color blindness (hereditary color blindness), the signs are often barely noticeable because you've always seen colors the same way. You may not know that there is another way of seeing color.
However, if you have acquired color blindness - meaning you are color blind from an injury or illness - you may notice the change in your color perception, although some diseases that affect color vision progress too slowly for changes to be noticeable.
Who is at risk of color blindness?
Most people with color blindness are born with the condition. It is passed down through her family. However, color blindness can also result from an eye injury, illness, or even certain medications.
You might be at higher risk for color blindness if you:
- are male.
- Are white.
- Do you have family members who are also color blind.
- Are you taking medications that alter your vision.
- Do you have eye diseases, includingage-related macular degeneration, GlaucomaorCataracts.
- suffer from Alzheimer's,DiabetesorMultiple Sklerose (MS).
Does color blindness cause other health problems?
Red-green color blindness, the most common form, does not lead to additional onesvision lossor total blindness. However, because the retina's cone cells also serve to see fine detail, people with color blindness may see less clearly.
The other, less common forms of color vision can be associated with other vision problems that need to be treated by an eye doctor - especially in children. Anyone who suspects color blindness should first schedule an eye exam.
If you or your child are color blind, talk to your eye doctor about tools that can help you see. If you ever notice other vision problems that come on suddenly and seem to be getting worse, contact your doctor right away.