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Dr. Dianna Leong, Dr. Anh Bui,
and Dr. Thomas Jay Yung

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Home » Eye Care Services » Questions & Answers on Colour Blindness with Dr. Leong

Questions & Answers on Colour Blindness with Dr. Leong

Are You Colour Blind?

Dr. Leong, answers some popular questions about colour blindness (AKA colour vision deficiency):
1. Why can’t I see colours at night?
There are 2 types of photoreceptors – rods and cones. Cones see colour, but they are not stimulated when it is too dark. Rods help you see at night, but they do not see colour. Green is the easiest colour to see when it is dark.
2. True or false: Colour blind people cannot tell the difference between red and green lights on traffic signals.
False. People with red-green colour blindness confuse some colours, but can discriminate many colours. They just see colours differently from the norm.
3. True or false: Colour blindness is more common in males
True. Colour deficiency is in 7% of males, usually genetically passed from the mother’s side of the family as the gene is on the X chromosome.
4. Did you know… colour deficiency can be acquired?
Example 1. Alcoholics lose some colour vision from insufficiency Vitamin B12. Reds will appear darker and less saturated.
Example 2. Viagra – a side effect of taking this medication is that colours may have a bluish tinge.
Did you know? Your Calgary AB eye doctors at Foresight Eyecare will even check for signs of cataracts as part of your comprehensive eye exam!