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Are you colour blind?

Life is filled with colour


When looking at a rainbow, most people can distinguish six distinct bands of colour – red, orange, yellow, green, blue, and violet.  However. people with colour deficiency, or colour blindness as it is commonly known, don’t perceive colour in the same way. For example, they may not distinguish between red and green, or even blue and yellow.


How do you become colour blind?

A person can be born with colour perception deficiencies.

Around eight in 100 males and four in 1000 females inherit colour deficiency. People may not even realise they have colour perception difficulties – it might take a random comment like “it looks more red to me” for it to be drawn to their attention that they are not seeing colour in the same way as everyone else.

Retinal eye disease such as macular degeneration, optic nerve diseases or brain damage can affect colour perception.

If you have cataracts, everything will appear more yellowy. In fact, Monet’s paintings became more yellow as his cataracts developed. When the cataracts are removed colours will appear more vibrant again.

Exposure to certain chemicals or using certain medications can also have an effect on your ability to see colours.



Does everyone have the same colour deficiency?

Red-green deficiency is the most common. It occurs when a person has abnormal pigment in the cone cells of the retina at the back of the eye.


The red, green and blue cones are responsible for us seeing colour. They each have a pigment that is receptive to certain wavelengths of light enabling us to see different colours. If you have difficulty seeing green (deuteranomaly), the cones for the colour green are defective, or difficulty seeing red (protanomaly) means the red cones do not work properly.

There is no treatment for either form of red-green deficiency.

Blue-yellow deficiency is rare

This combination affects around one in 10,000 people; men and women equally. It is caused by a mutation on chromosome 7 (tritanomaly), causing confusion of blue colour with green and yellow with violet.


Can colour deficiencies be cured?

If you’ve inherited a colour deficiency, it can’t be cured. If your problem has been caused by medicines or chemicals, eliminating these may improve your colour perception.

Special colour filter lenses can help expand the range of distinguishable colours while also making them more vivid, but they can’t cure colour deficiency.

Why is it important to know if you have a colour deficiency?

Certain occupations or professions only accept people with normal colour vision

Commercial pilots, commissioned officers in the armed services, some maritime roles, police officers and electricians must reach acceptable colour vision standards.

Jobs such as decorators, fashion designers, fruit graders and people in the painting or printing industries require you to judge colour accurately.


Can you see the numbers 3 and 29 in these pictures?

If not, or if you have any concerns about your colour vision, contact one of our Black Gates Optometrists practices for an appointment with an optometrist.


If you are concerned about your eyesight or your ability to see colour, one of our optometrists would be happy to discuss your concerns. Book an appointment today with our Wellington optometrists at our Lower Hutt or Johnsonville clinics.