Serendipity plays a big role in science. Many discoveries begin with a puzzling observation followed by, “That’s weird”. Don McPherson developed special lenses for surgeons to use when employing lasers and he lent them to a colour blind friend on a Frisbee field. His friend reported he could now see the orange cones on the field. He’d never seen them before. That’s weird.
But not every “that’s weird” moment results in game-changing technology.
Colour blindness is rarely mentioned in the media. As a challenge, can you think of three characters who are colour blind? And yet, it’s a common condition, affecting 9% of men and 0.6% of women among Whites. You may be familiar with the bubbly colour images, like Roman mosaic floors, used by optometrists to detect it (it’s called the Ishihara colour test). The underlying problem is that at least one of the three types of colour-detecting cells in the eye—red, green, and blue cones—is not working.
For those who want to delve deeper into “What are the different types of colour blindness out there?“, click here
Colour blindness comes in different varieties. For some, it’s the red cone cell that is either abnormal or completely broken (protanomaly and protanopia, respectively). For others, it’s the green cone that is affected or isn’t working (deuteranomaly or deuteranopia). There are less common forms of the condition, where the blue cone cells are impaired (so that green appears blueish and yellow looks pink) and even where all three cones are defective, meaning that the person sees the world in shades of gray.
The reason why many more men than women have the most common types of colour blindness is that the genes coding for the red and green cones are found on the X chromosome. Because women have two X chromosomes, a mutated copy of one of its genes can be “offset” by the healthy copy on the other X chromosome. Men, however, have no such back-up
Interesting aside, the gene coding for the blue cone, OPN1SW, is actually found on chromosome 7, of which both men and women have two copies, so this rare type of colour blindness affects both sexes equally.
There currently exists no cure for colour blindness. You may be wondering if that’s even worth looking into, but there are consequences to not seeing colours the way most people do. Deciding how ripe a fruit is before eating it can be challenging, and learning at school when pie charts and colour-coded graphs are used is not as easy for someone who is colour blind, especially if they are undiagnosed. And a career in fashion could be thorny.
So when Don McPherson—he of the lenses that made his buddy see orange cones on a green field for the first time—released EnChroma glasses, many people were excited. These FDA-approved spectacles look like the sunglasses Cyclops wore in the X-Men movies; they cost between 350 and 570$ depending on the model; and they’re being marketed as “a new frontier in colour blind technology.”
And video evidence is hard to dismiss. There are compilations of people trying on the glasses for the first time and crying. Colour blind men put the glasses on and see that the crayons in front of them come in more than five colours and that two bluish flowers which looked identical actually have different tints. And if you feel like celebrating that, the glasses ship with six colour balloons.
But an independent scientific study just published is draining the colours from this neat tableau.
In it, a group of Spanish researchers recruited 48 volunteers who all took the colour blindness test on the EnChroma website and were recommended the glasses. These volunteers twice went through the same battery of tests at least two weeks apart, once without and later with the EnChroma glasses. These tests included the famous Ishihara plates screening method. Moreover, the glasses themselves were analyzed in many ways, such as exactly which parts of the light spectrum they filter out.
The conclusion the scientists came to is that, while the glasses change the way colours will appear to their wearer, they do not make the world look more like it does to normally sighted people. Quite telling is when the researchers asked their 48 volunteers at the end of the experiment to look at their surroundings with the EnChroma glasses and tell them if they noticed an improvement in colour perception. Only one said yes.
So how do we square this with the videos showing people crying of joy after putting on the glasses for the first time? The most obvious answer is selection bias. The videos of people putting the glasses on and not seeing an improvement simply don’t get released or, if they do, they don’t get publicized and die on the vine of unpopular videos. Who wants to see a colour blind man putting on fancy glasses and saying “meh”?
That being said, the study is far from perfect. Forty-eight people is not enough to make a convincing case in a study of this type. Also, the study authors did not report on the age range of the people they tested, their contrast sensitivity, any other eye problem they may have and, most importantly, how many people had which type of colour blindness. The EnChroma website states their glasses are mainly made for people with impaired red or green cones, but some of the participants in the study had fully inactivated red or green cones (protanopia and deuteranopia). This muddies the waters. But to play devil’s advocate, why were these people recommended the glasses through EnChroma’s website in the first place?
Also, EnChroma recommends wearing the glasses for at least ten hours over the course of one or two weeks to allow the brain to fully adapt, but the researchers only gave the participants 30 minutes to adapt. The devil’s advocate pops up again, however, because in the video testimonials, people are having their “road to Damascus” moment instantly, so how much time really is needed for this adaptation to occur?
This is not a definitive study. If EnChroma was genuinely interested in settling this issue once and for all, it would approach an independent lab, give them the glasses, ask them to pre-register the study, and let the chips fall where they may. But as a colleague put it to me, given that most research hypotheses don’t pan out, it would be like playing Russian roulette where only one chamber is empty.
You may wonder why these glasses received FDA approval if they don’t actually work. The FDA is mainly concerned with preventing harm, not with proving efficacy. Per the EnChroma user manual, the FDA approved them because they block UVA and UVB rays and because the lenses passed the drop-ball test for impact resistance. That’s it.
So what’s my take on the EnChroma glasses? They may improve colour discrimination in some people with some milder forms of colour blindness, although there is now evidence that they simply shift the problem around, making some colours easier to differentiate while muddying other parts of the spectrum. This evidence is neither conclusive nor easily dismissed. And the glasses have a 60-day “worry-free” return policy.
If you’re colour blind and want to give these glasses a try, go for it. But try not to let the emotional marketing videos colour your expectations too much.
- Colour blindness is the difficulty or inability to distinguish certain colours
- EnChroma glasses can allegedly help people with colour blindness see colours normally
- The first major independent study of these glasses was just published and, while it is flawed, its results suggest the glasses will not work for most colour blind people
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