What is colorblindness and what causes it?

What is colorblindness?

Colorblindness a.k.a CVD (Color Vision Deficiency) is where individuals look at colors differently from others. What do I mean by this? Imagine playing Dress to Impress with your friends except in your version of the game, the colors are a bit off. The bright reds looked greenish. That's kind of what colorblindness is like. It doesn't mean that you don't see colors, it just means that the way someone with CVD looks at colors is different than others.

How does color vision work?

Eyes have photoreceptor (light receptor) cells called cones that come in three types: red, green and blue. These three work together to help you watch the full spectrum of colors. When one type of cone isn’t working properly or is missing, your brain doesn’t get the full color story - and that’s when CVD enters the chat.

What causes colorblindness?

These include a variety of factors. Let's look at each:

First, the most common cause: genetics. It is inherited via the X chromosome. Males have 1 X and 1 Y chromosome, so they are most likely to carry it. Females have 2 X chromosomes, so the probability of them being colorblind is lower. Why so? They are only colorblind if they inherit it on both chromosomes. The most common type via genetics is red-green colorblindness.

Second: diseases. This includes conditions like glaucoma, anemia, macular degeneration, Parkinson's disease, chronic alcoholism, leukemia, Alzheimer's disease, multiple sclerosis, macular degeneration and diabetes. 

Fourth: chemicals/medicines can also interfere with the function of the cones. An example is hydrochloroquine, a medicine used to treat rheumatoid arthritis.

Fifth: injury, surgery, radiation or laser treatment. 

Conclusion

Colorblindness isn't a black and white world - it's simply a different filter for the same picture. Research suggests everyone perceives color differently. Those who are colorblind just have a very different perception.

So next time your friend says your 'blue' shirt is purple… they might not be wrong. They just see the world a little differently. And that? That’s kinda beautiful.