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A Quick Guide to Color Blindness

A Quick Guide to Color Blindness

What’s one of the biggest misconceptions about color blindness? Many people without the condition imagine it is like watching television or a movie in black and white. In reality, it is much more complex than this, and there are different types of color blindness that influence how you see color - and the world, for that matter! Whether you have the condition or a loved one does, it is important to have some background knowledge. What do you need to know? 

Color Blindness and Genetics 

Color blindness is typically genetic. It is determined by a recessive gene on the X chromosome, which is one of the two sex chromosomes - Y being the other. Approximately 8% of men are color blind, while only 1% of women are. Genes tell us why.

Women have two X chromosomes, while men have an X and a Y. Now, this means that in order to be colorblind, women need to have two copies of the gene. If they have one copy, they can be a carrier of the condition without symptoms (this means they may pass it on to their children. Most children get their X chromosome from their mother). Men, on the other hand, will be colorblind if their single X chromosome contains the gene. This is why the condition is much more prevalent among males. 

If you are born with color blindness, it will not get better or worse throughout life. It just is. However, it is possible to develop an acquired color blindness. This affects men and women at the same rate. It can be caused by accidents or strokes that damage the retina or specific areas of brain/eye. Some antibiotics, barbiturates, anti-tuberculosis drugs, high blood pressure medications, and drugs used to treat nervous disorders can also cause acquired color blindness. 

If you experience any change in your ability to see color or discern among shades/hues, please contact Asheville Vision.

How We See Color 

Our eyes are amazingly complex organs. The retina is a layer in the back of the eyeball that contains light-sensitive rods (which allow us to see in low-light conditions) and cones (which allow us to see color). These cells trigger nerve impulses that travel from the optic nerve to the brain in order to form an image. 

Color vision is trichromatic: we have cones that are sensitive to long (red), medium (green), and short (blue) wavelengths. When one or more of these cones do not work properly, it results in colorblindness. 

Different Types of Color Blindness 

As mentioned, there are different types of colorblindness:

Red/Green. This is, by far, the most common form of colorblindness. If the long (red) or medium (green) cones are not working properly, you will be red/green colorblind. Colors with red or green in them will appear muddier, duller, or as a yellowish-brown. 

This can impact life in a variety of ways. It may be hard to tell when a steak is done or tomato is ripe, for example, but it can also be difficult to distinguish between red and green at traffic lights. It will limit your ability to enter into certain professions (e.g. flying in the Air Force, electrical engineering) - but it need not have a detrimental effect on your quality of life. 

Blue/Yellow. This is much rarer than red/green colorblindness. Here, the blue cones are not working properly, and you’ll see a spectrum of browns, pinks, and teals. Typically, folks confuse blue with green and yellow with violet or light grey.

Monochromacy. This is very rare. Rod monochromatism, also called achromatopsia, is complete color blindness. People with this condition can only see in shades of grey and are typically quite sensitive to light. Vision tends to be blurry as well because cones allow for sharp detail in vision. 

There are even more rare forms of monochromatism, such as blue-cone monochromacy: here, you are completely color blind but have some level of color perception in twilight conditions. Again, these forms of color blindness are exceedingly uncommon. 

A Different Way of Seeing the World 

“Colorblindness” is a bit of a misnomer. Unless you have complete monochromacy, you do see color. A better phrase may be “color deficient.” A person with normal color vision can tell about 100 different hues from each other; for a person with strong color blindness, it drops to about 20. Still… this is 20 shades and tones you can see. While some tasks may be more difficult… or you may pick a few under-ripe tomatoes… life does not have to be negatively impacted. 

Will special glasses help? If you have mild anomalous trichromat - i.e. your cones overlap too much and are activated by the same stimulants - corrective glasses can help by blocking out certain wavelengths of light. They may improve your ability to discern colors but will not give you “normal” color vision. 

While glasses may not help you, information and guidance can. There are resources out there to help you find out more about color blindness and navigate your way through the condition. Contact Asheville Vision to get an exam, speak with an expert, and learn more about adapting to life with color blindness.