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What is colour blindness

Updated on August 18, 2012

What is it?

The inability to differentiate between different colours, under normal light conditions is known as colour blindness. No one is really in a state of black and white! But they find it difficult to differentiate between certain colours like blue, green, orange etc. A person can have varying degrees of colour blindness depending on the number of colours and the extent to which he or she has a problem in identifying them.

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Add colour to your life.. | Source

What causes colour blindness?

This is usually congenital or something that you are born with. This implies that it is inherited and is genetic. Though it has been observed that, more men compared to women suffer from colour blindness. Women are usually ‘carriers’ and pass it on to babies they give birth to. The reason for this is that males have only the X chromosome and this carries the genes that produce the photopigments; if they lack these genes, it causes colour blindness. Whereas women have two X chromosomes and a good gene in any one of them is enough to produce sufficient photopigments. A girl baby will be colour blind only of her father is colour blind and her mother is a carrier.

The human eye and the retina in particular consists of two types of cells – rods and cones.

Rods – these cells help us define grey and black and assist in finding our way in the dark or night.

Cones- these cells perceive different colours.

Thus a colour blind person lacks cone cells in particular in his/her retina.

How to test for colour blindness?

Back in school days, in Grade 6, as part of a regular medical check up I underwent a colour blindness test. I was shown a book and each page had a circle of various dots of different colours. Within those different colours are numbers in a specific colour. The medical assistant asked me to identify the numbers while he flipped the pages quickly. This was years ago. Today the test for colour blindness maybe more automated and can be done online too.


Colour Blindness is not a disease or a disability

Do understand, even though the word ‘blindness’ is used, it is nothing close to the level of disability that is faced by a blind or partially blind person. In fact it is preferably termed as colour vision deficiency or problem. Many people in fact don’t even realize they have a colour blindness problem, till a job or skill set puts them in a position to differentiate colours. Most folks lead regular healthy lives in oblivion of the colour blindness they might or might not have. The impact on ones daily life is almost negligible. Although it might affect a child’s learning ability and hence there is no harm in getting a colour blind test done for your child as young as 4-5 years of age just to ensure that they do not require special help in their schooling years.

Since we know for a fact it is not a disease, there is no cure for inherited colour blindness!

What are some of the things you cannot do, if you are colour blind?

Occupations that are of high risk in nature and require the strong differentiation of basic colours will be some of the very few professions that colour blind people may not be able to take up. For example to join the military, one goes through rigorous medical and physical tests. They might not allow you to be accepted in certain branches of the military if you are colour blind. One may not be allowed to be a commercial pilot if you have colour blindness. Similarly you may not be able to obtain a commercial drivers license as well, although you may be licensed to drive your personal vehicle.

Yet, the impact of colour blindness on your career options is extremely limited.

Famous personalities who were colour blind

Paul Newman

Bing Crosby

Meat Loaf

Mark Twain


John Dalton (1766-1844) was an English physicist who first proposed the theory behind colour blindness and existence of variances in peoples colour differentiating abilities. Thus ‘Daltonism’ was also a term used to define ‘colour blindness’.

“I cannot pretend to be impartial about the colours. I rejoice with the brilliant ones, and am genuinely sorry for the poor browns” – Winston Churchill


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    • Riverfish24 profile image

      Riverfish24 5 years ago from United States

      Yup! Thanks Cassylu!!

    • CassyLu1981 profile image

      CassyLu1981 5 years ago from Spring Lake, NC

      Wow, Meat Loaf was color blind, and Mark Twain, huh, who knew :) I couldn't imagine being color blind. That has got to be so hard. Great hub, voted up and shared!

    • watergeek profile image

      watergeek 5 years ago from Pasadena CA

      My father was red/green colorblind. I thought I might be some kind of black colorblind, until I realized I just hadn't tried to differentiate between all the shades of black. Now dark navy is as clearly navy as black is black.

    • krsharp05 profile image

      Kristi Sharp 5 years ago from Born in Missouri. Raised in Minnesota.

      Very interesting information about being color blind. I'm such a color addict that I can't imagine a world without rainbows.....and chocolate. Excellent hub. Poor Meatloaf.

    • tamarawilhite profile image

      Tamara Wilhite 5 years ago from Fort Worth, Texas

      We realized my son was color blind as a toddler. He couldn't follow instructions like "get the red ball" and would bring the blue one, but he picked the right item when told "get the bigger one" or "get the checkered ball".

    • leahlefler profile image

      Leah Lefler 5 years ago from Western New York

      It is always a good idea to get a full vision exam before a child starts kindergarten - color blindness can be caught early!

    • Riverfish24 profile image

      Riverfish24 5 years ago from United States

      Thanks for the input tamarawilhite!

    • tamarawilhite profile image

      Tamara Wilhite 5 years ago from Fort Worth, Texas

      Red green colorblindness and red-blue colorblindness are two separate traits, and you can inherit either one (or in rare cases, both). Red-green color blindness is simply more common than red-blue.

    • Riverfish24 profile image

      Riverfish24 5 years ago from United States

      Yes, apparently he was. But how does that matter to what he wrote, he wrote great stories! :)

    • Om Paramapoonya profile image

      Om Paramapoonya 5 years ago

      Mark Twain was color blind? He's one of my favorite authors and I had no idea he had this abnormality. Thanks for sharing these interesting facts and trivia, Riverfish.