Do you see what I see? There’s a high probability you don’t.

That’s because I’m colour blind. It’s a surprisingly common condition, affecting more than 350 million people – mostly men – worldwide. One in 24 children are colour blind. Yet, outside of a small scientific circle, it’s remarkably poorly understood. And that’s a problem.

As anyone who is colour blind can attest, telling people about your condition rarely leads to helpful responses.

"When people know you’re colour blind, they mainly want to point at objects and ask, ‘What colour is that’, and, A, that’s tiresome and, B, it’s not like that," he says.

Colour blindness has a remarkable number of variations. For most sufferers, it’s a matter of not distinguishing purples from blues and pinks from greys, of struggling to interpret charts and tell off lights from on, of being underwhelmed by autumn foliage and Christmas decorations.

Given that lack of understanding, the standard response of sufferers seems to be to avoid situations where they might be exposed and to adapt.

A human with normal colour vision has four types of vision cells in their retina, at the back of their eye: rods, which provide low-light, monochromatic sight and three types of cones, which detect colour.

As with undiagnosed dyslexia, a lack of awareness can leave teachers, parents and kids themselves thinking sufferers are just a bit dim or badly behaved
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In those with colour blindness, the cones are faulty, with the most common being those triggered by green light, followed by those for red and, very rarely, blue. Some are missing a set of cones entirely (dichromacy) – these people see around 1 per cent of the colour those with normal vision do.

As humanity’s ability to recreate an ever-growing spectrum of colours has grown, so colour has become more central to our lives, all the while making it harder for the colour blind.

Nowhere is this more true than in education.

As with undiagnosed dyslexia, a lack of awareness can leave teachers, parents and kids themselves thinking they’re just a bit dim or badly behaved.

Claire Wills has two sons, Milo aged nine and Rafe aged six, both of whom are colour blind. Claire’s own father was colour blind, so she recognised the condition early on with Milo. At school, he became unusually anxious and shy.

"He started saying he wasn’t good enough, he wasn’t quick enough, he wasn’t the same as his friends," explains Claire.

Milo was marked as an additional needs pupil because of his anxiety, but this did little to help. His special educational needs coordinator didn’t understand colour blindness, says Claire, and even wrote on his educational plan "if he tried harder it wouldn’t be a problem".

While a change of head teacher has improved things, Claire worries about what will happen when Milo reaches secondary school.

Geography and chemistry are notoriously difficult for the colour blind, but interactive whiteboards and other tech are spreading colour into new lessons.

Part of the problem is that teachers are simply not given any information about colour blindness.

One area of progress is in testing. Prof Franklin and her team have developed a test called ColourSpot, which can be used on a tablet with no need for a trained professional.

Meanwhile, society is making some simple but important adjustments, too. Many video games now have colour-blind modes built in, football’s governing bodies have moved to a system of dark and light kits to help the colour blind.

So what hope is there for simply eradicating the problem?

Recent work suggests that the problem of colour blindness is concentrated entirely in the faulty cone cells – and that the wiring in the brain required for full-colour vision is all there. Such findings have led the eyewear company Enchroma to develop glasses to help with colour blindness.

When I gave the glasses a try, reds became much more vibrant – brake lights were brighter, buses stood out from further away and red flowers were suddenly vivid.

After more than a week, however, I’m yet to notice much difference with greens and I would label the glasses as interesting, rather than life-changing.

The glasses use a technology known as notch filtering to block out a narrow band of light that, in colour blind eyes, causes red and green cones to overlap too much – restoring their ability to differentiate between colours. The exciting thing is that the brains of colour blind people appear to be receptive to this effect.

Prof John Werner is an expert in colour vision at the University of California, Davis and co-authored a small 2019 study that found that the effects of wearing notch filter lenses persisted even after the glasses were removed.

He compares it to acquired taste.

That suggests that there’s plenty of scope for treatments and, tantalisingly, a cure. Professors Jay Neitz and Maureen Neitz, a couple at the University of Washington, are arguably the leading figures in colour vision research. In 2009, they successfully used gene therapy to restore colour vision to a dichromat squirrel monkey. The process worked by inserting a modified virus containing the genes for correctly functioning red cones into the monkey’s eyes.

Prof Neitz now has what he calls a "candidate" that he believes would cure colour blindness in humans. He’s not, though, anywhere close to ordering the fireworks.

The Daily Telegraph

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