How do you see the world?
You may be surprised to discover you see the world differently from everyone else. Before Twitter debates began to crop up hotly debating whether a dress was turquoise or gold, we may have assumed that everyone sees the same colour when looking an object. What those debates showed is that how we perceive an object is different than what we see. Objects absorb light and reflect specific colours but our perception of colour can be altered by our genetic code, and these differences may be classified as colour blindness. Read on to learn more…
What is colour blindness?
The retina is lined with millions of cells known as rods and cones that transmit the colours reflected off of objects, relaying light sensitive signals to our brains via the optic nerve and pathway. Rod cells are sensitive to different levels of light, while cone cells (humans have three types) differentiate between colours and shades. If there is a deficiency in one or all of these cones then it can affect your perception of colour, resulting in colour (color) blindness also known as colour vision deficiency, or CVD. CVD affects nearly 300 million people worldwide and is more common in men then women.
What causes colour blindness?
There are several kinds of pigments present in your three types of cone cells. Web MD notes that some react to short-wavelength light, others react to medium wavelengths, and others react to higher wavelengths. If your cone cells don’t have all of the pigments you will process colour differently than you will not see the way everyone else does. Colour-blindness is most often genetic, but has been known to develop over time with age or diseases like diabetes and multiple sclerosis (MS) and some medications.
Does being colour blind mean I have bad eyesight?
A better term for colour blindness would probably be colour deficient, since those with the condition can still perceive colour; their brain merely translates what they see differently. If you are colour-blind, it usually doesn’t have anything to do with how sharp your vision is or how much light you can see, it just means that your cone cells process colours differently.
How do I know if I am colour blind?
Colour blindness is typically diagnosed by the Ishihara colour test, named for Japanese ophthalmologist Ishihara Shinobu, a professor at the University of Tokyo who developed the screening in 1918 for the military. The test shows a number of plates with a number or figure embedded in a background filled with a different colour. The numbers or figures you are able to see will determine which colours you may not be able to distinguish. For example, if someone is red-green colour blind they may not distinguish between those colours and see browns instead.
What colours can a colour-blind person see?
According to colourblindawareness.org, most people who are colour-blind are unable to fully see red, green or blue light. There are different types of colour blindness and there are extremely rare cases where people are unable to see any colour at all.
What are the three types of colour blindness?
The three types of colour blindness are: red-green colour blindness, blue-yellow colour blindness, and the very rare complete colour blindness. Within these types there are different subgroups outlined below.
Red-Green Colour Blindness Categories include:
- Deuteranomaly- the most common type of red-green colour blindness where greens will have a redder shade and it causes difficulty in distinguishing between reds, greens, browns and oranges.
- Protanomaly- the opposite of deuteranomaly, protanomaly makes red look more green and less bright. This reduced sensitivity to red light makes it difficult to distinguish between reds, greens, browns and oranges.
- Protanopia and Deuteranopia – make you unable to tell any difference between red and green altogether.
Blue-Yellow Colour Blindness Categories include:
- Tritanomaly- makes blue and green hard to differentiate along with red and yellow.
- Tritanopia- makes it difficult to tell the difference between certain combinations of colours like blue/green, purple/red, and yellow/pink making all colours less bright. This is generally rare.
If you suffer from the third type of colour blindness known as monochromacy you won’t see any colour and the world around you will be grey. In some cases, it can affect shapes as well as visual acuity. This extremely rare condition usually occurs because of a defect in the rods and cones of the retina.
Should I worry if I’m colour blind?
Not if you’ve always had it. Most people who are colour-blind still have visual acuity, do well in their eye exams and screenings and aren’t even aware of their subtle differences in perceiving colour. It can negatively affect those who are seeking to go into a profession that requires colour acuity and those who suffer from monochromacy. The American Academy of Ophthalmology suggests having an eye exam if there is a sudden onset of vision problems affecting your colour vision as it may be related to other eye conditions such as: glaucoma, cataracts or macular degeneration.
Is there a treatment for colour blindness?
Not really. There are options and new products coming to market all the time including colour blind glasses that can alter your perception of colour, enhancing the colours that the wearer has difficulty perceiving. This may be helpful when shopping for clothes or for broadening your career options.
Should I get tested for colour blindness?
Since the condition is genetic, most people that are colour-blind have had it since birth and aren’t even aware of their differences in colour perception. If you are seeking a career where colour perception is important such as an electrician, commercial artist, designer, technician, or certain jobs in manufacturing and marketing then you should be tested.
Are online colour-blind tests accurate?
Exact colour representation is essential in order for a colour-blind test to be accurate, and due to variations in our computer screens and what is presented on a site, results from online colour-blind tests are not very effective according to All About Vision. For the most accurate results, see your eye doctor and take a colour-blind test administered using standardized testing materials under proper lighting.