Are we about to find a cure for colour blindness?
Daniel Capurro, among the one in 12 men afflicted, tests a new pair of £200 glasses promising long-awaited hope for sufferers
DA small study found the effects of wearing notch filter lenses persisted even after the glasses were removed
o 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 350million 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 – such as Lord Hague, the former Conservative Party leader – 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.
As Lord Hague explains, “My reaction was just to shed anything where I might have needed to use colour. And otherwise not to make an issue of it.”
When Britain intervened in Libya in 2011, both Lord Hague, then foreign secretary, and the defence secretary Dr Liam Fox were colour blind.
“In the National Security Council, we had to ask the military to do their maps differently. When we were looking at the military picture in Libya, we were seeing a different picture to everybody else,” says Lord Hague, chuckling. “If you’re in charge, like I often was, you can ask people to do things differently. The problem is for people who are not in charge of their surroundings.”
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.
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 one 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.
In 2009, after a cost-cutting review, colour blindness tests for all schoolchildren were scrapped. This was done, says Anna Franklin, professor of visual perception and cognition at the University of Sussex, on the basis of outdated research from the 1960s which found that colour blind children performed no worse academically than their peers.
“Teaching materials would’ve been in black and white [then], but in the modern day, all aspects of education are colour coded,” she says. “One study which looked at textbooks found that 10 per cent of the material is completely inaccessible to colour blind pupils.” 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. My own earliest memory of colour problems was being berated by a teacher, aged 10, for colouring the sky purple.
At secondary school, I had to get classmates to annotate test papers, and often had the nagging sense that something was “wrong” with me. 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 colourblind modes built in, football’s governing bodies have moved to a system of dark and light kits to help the colour blind, while last week World Rugby announced it would stop any red-green kit clashes.
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.
Videos showing colour blind people bursting into tears upon trying the glasses have gone viral, though the company itself says only 30 per cent of users will experience such a moment. For most, it’s likely to be a slower, more subtle effect. For some, the glasses – which cost £200 – won’t work at all.
“If you buy our glasses, you have two entire months to wear them, try them and if they don’t work for you, you can return them,” says Erik Ritchie, Enchroma’s chief executive.
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, cause 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. “When somebody doesn’t drink wine, one glass tastes the same as the other, but after experience you become sensitive to the differences.”
That suggests that there’s plenty of scope for treatments and, tantalisingly, a cure.
Professors Jay Neitz and Maureen Neitz, a married 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.
Some of the issues are ethical. It simply isn’t worth the risk of losing all vision for someone with mild colour blindness to trial the Neitzes’ treatment. To get corporate backing, they will need to prove that there’s a market out there for the product – so the answer lies in spreading the word, says Prof Neitz. “I met one teacher while running tests who said, ‘I’m aware this is important, but I’ve never had a colour blind kid in my classroom’. I said, ‘You have two right now’.”