Specially designed glasses have been found to help people with colour blindness see reds, yellows and greens.


Colour blindness, or colour vision deficiency, is a fairly common condition, affecting around 1 in 12 men and 1 in 200 women. Individuals who are unable to distinguish between different shades of red, yellow and green, have what is known as red-green colour vision deficiency.

Red-green colour blindness is a genetic condition, affecting genes on the X chromosome that code for light receptors in the eye. In particular, it is the medium- and long-wave photoreceptors that are affected, which means the colours to the left of the visible light spectrum, with longer wavelengths, aren’t as easily distinguished from each other.

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In the study by researchers at the University of California, which has been published in the journal Current Biology, colour blind participants were given EnChroma glasses, the lenses of which have a special filter that can increase the separation between colours’ wavelengths. This helps the photoreceptors in the eye to pick out different hues more clearly and vibrantly.

“Extended usage of these glasses boosts chromatic response,” said John S. Werner, professor of ophthalmology at University of California Davis Health. “We found that sustained use over two weeks not only led to increased chromatic contrast response, but, importantly, these improvements persisted when tested without the filters, thereby demonstrating an adaptive visual response.”


One colour blind participant in the study, Alex Zbylut, said the glasses would help people like him better navigate colours. “When I wear the glasses outside, all the colours are extremely vibrant and saturated, and I can look at trees and clearly tell that each tree has a slightly different shade of green compared to the rest," said Zbylut. "I had no idea how colourful the world is.”

Reader Q&A: Do we all see the same colours?

Asked by: Jake Bogdan, Switzerland

A minority of people are ‘colour blind’, in that they see colours as duller than usual and have difficulty distinguishing certain colours.

These problems aside, whether your experience of red is the same as mine is a tricky philosophical question because we can never truly know each other’s subjective experience. What’s for sure is that the same object can be perceived as being a different colour by different people, depending on the assumptions their brains make about the background lighting.

Just look at the ferocious internet argument in 2015 over whether a striped dress – pictured on Tumblr – was white and gold or blue and black (check out ‘the dress’ to read more).

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Amy ArthurEditorial Assistant, BBC Science Focus

Amy is the Editorial Assistant at BBC Science Focus. Her BA degree specialised in science publishing and she has been working as a journalist since graduating in 2018. In 2020, Amy was named Editorial Assistant of the Year by the British Society of Magazine Editors. She looks after all things books, culture and media. Her interests range from natural history and wildlife, to women in STEM and accessibility tech.