How Do We See Colour? Your Eyes are a Marvel of Nature

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Blog by Envision Eye Care

Our eyes are very literally how we see the world, so it’s a must that your eyes are well taken care of. They distinguish the colours we can see, but have you ever wondered exactly HOW we see colour and whether everyone sees colours the same way?

The process that our eyes use to interpret colour is actually pretty remarkable! Their ability to take in light and turn it into the wide spectrum of colours we can see is amazing. Our eye care experts take a deeper look!

What is colour?

In the most basic sense colour is the reflection of light. It is not actually IN things, but appears based on how the surface absorbs and reflects light. The wavelengths of light that get reflected are the colours we see, and all others are absorbed by the object. The colour black exists when all wavelengths are absorbed by the object.

Colour is made up of blue, green and red light- all primary colours of the colour spectrum. White is created when balanced amounts of all of these colours are combined. All of the colours within the colour spectrum can be created by varying the amounts of the blue, green and red lights.

The basic anatomy of your eye

Sclera (white part of your eye)- protects the eyeball

Pupil (black dot at the center of your eye)- the hole where light enters your eye

Iris (coloured part of your eye)- changes the size of the pupil to control how much light can enter your eye

Cornea (the clear covering on the front of your eye)- protects the iris and pupil

Lens (clear covering on the inside of the eye, behind the pupil)- focuses light onto the retina, almost like a camera

Retina (inner lining of the back of your eye)- holds the cones and rods that turn light into electrical impulses

Optic nerve– carries those electrical impulses to the brain

How our eyes see colour

Not seeing colours the way you think you should? It may be time for an eye exam, or to speak to your optometrist.

Light is reflected off an object and into your eye. This light is passed through the pupil and into the retina of your eye. There the rods and cones receive the light waves and turn them into nerve impulses which are then sent through the optic nerve to your brain for decoding.

Rods and Cones

Rods and cones are the light receptors in your eye that make seeing different colours and shades possible. The rods transmit mostly black and white to the brain, while the cones transmit mostly colours.

Rods are mostly concentrated around the edge of the retina, not the center, which explains why your peripheral vision is less sharp and colourful than your front-on vision. Rods are also more sensitive to dim light so you lose most of your colour vision in dusky and darker conditions.

Cones are mostly in the middle of the retina. These are responsible for receiving and transmitting the more intense lights that are associated with colours. There are 3 different types of cone-shaped cells, each focused on the long, medium or short wavelengths of light. Working together with nerve cells these different cones send enough information to the brain to interpret and name colours. Interestingly, the human eye can notice more variation in warmer colours (reds, oranges and yellows) than cooler ones (blues, greens and purples) because around 2/3 of the cones in your eye are dedicated to the longer light wavelengths responsible for warm colours.

Colour Impairment and Blindness

About 8% of men and under 1% of women worldwide have some form of colour vision deficiency. The most common colour impairment is a reduced sensitivity to green light, though it is possible to have reduced sensitivity to other colours. Total colour blindness is very rare, appearing in only about 1 in 33 000 people.

Our eyes are remarkable!

Our eyes are truly amazing with all they are capable of interpreting and showing us! Be sure to keep them in top shape by getting them checked regularly. You don’t want to chance losing your vision before you’ve seen all that the world has to offer!