A Scientist Accidentally Developed Sunglasses That Could Correct Color Blindness

One afternoon in 2005, Don McPherson was playing ultimate Frisbee in Santa Cruz. He was wearing a pair of sunglasses, when his friend, Michael Angell, admiring his eyewear, asked to borrow them. When he put the glasses on, he was stunned by what he saw.

McPherson recalls Angell saying, with surprise, “I can see the cones,” referring to a set of orange traffic cones nearby. What made this a startling observation was that Angell had been colorblind his whole life. The sunglasses, which McPherson, a materials scientist, had engineered, actually allowed him to see the orange hue for the first time,  and distinguish that color from the surrounding grass and concrete.

Based in Berkeley, California, McPherson, who has a PhD in glass science from Alfred University, originally specialized in creating eyewear for doctors to use as protection during laser surgery. Rare earth iron embedded in the glasses absorbed a significant amount of light, enabling surgeons to not only stay safe, but also clearly differentiate between blood and tissue during procedures.

In fact, surgeons loved the glasses so much, they began disappearing from operating rooms. This was the first indication that they could be used outside the hospital. McPherson, too, began casually wearing them, as sunglasses. “Wearing them makes all colors look incredibly saturated,” he says. “It makes the world look really bright.”

It wasn’t until Angell borrowed his sunglasses at the Frisbee game, however, that McPherson realized they could serve a broader purpose and help those who are colorblind. After making this discovery, he spent time researching colorblindness, a condition he knew very little about, and ultimately applied for a grant from the National Institutes of Health to begin conducting clinical trials.

Since then, McPherson and two colleagues, Tony Dykes and Andrew Schmeder, founded EnChroma Labs, a company dedicated to developing everyday sunglasses for the 300 million people in the world with color vision deficiency. They've been selling glasses, with sporty and trendy, Ray-Ban-like frames, since December 2012, at a price point ranging from $325 to $450. The EnChroma team has refined the product significantly, most recently changing the lenses from glass to a much more consumer-friendly polycarbonate in December 2014.

While it was a fortuitous discovery, McPherson emphasizes that the eventual manufacturing and execution of the product is based on years of rigorous science. The creators are constantly experimenting with new iterations. “My bike bag has about ten pairs of glasses in it, different versions," he says.

To further bolster the effect of the glasses, Schmeder, a mathematician, created a sophisticated model of color vision in the human eye that incorporates 10,000 natural and man-made colors. Informed by this, he designed a filter for the eyewear that optimizes the way a user views this wide spectrum of hues.  

The glasses are built on fundamental vision science. McPherson explains that all people have three photopigments in the eye, also known as cones, which are sensitive to blue, green and red. Blue operates fairly independently, while the red and green cones, in most humans, overlap, affecting the perception of certain colors. For example, if 10 photons landed on the red cone and 100 landed on the green cone, the object viewed would appear more green. Whereas if an equal number of photons landed on the red and green cones, the color perceived would be yellow.

A problem arises when the red-green cones overlap too much, a condition that accounts for 99 percent of colorblindness cases. When this happens, in the previous scenario, instead of yellow, an individual would perceive little, if any color. EnChroma’s technology works by placing a band of absorption on glasses that captures light, pushing the cones away from each other and reestablishing the normal distribution of photons on them.

The company’s eyewear is able to treat up to 80 percent of the customers who come to them. The remaining 20 percent, including the writer of this recent Atlantic article, who tested the glasses, are missing an entire class of photopigments, either green or red—a condition EnChroma is not currently able to address.

This year will be a busy one for the company, which is focused on rolling out indoor versions of the glasses, a pediatric model and an online test that can help people analyze colorblindness at home. For children especially, wearing EnChroma glasses could help correct their colorblindness and prevent it from progressing further. In order to scale the product, the team is recruiting opticians and optometrists around the country to test and share the glasses with their patients.

Marc Drucker, a user who has had red-green colorblindness his whole life, now wears his sunglasses on a regular basis. “Just trying them on, it was really transformative," he says. "It’s very strange seeing things differently for the first time in 45 years.”

McPherson says, “It still gives me goosebumps when someone bends down, and sees a flower and asks, ‘Is that lavender?’” Simple, everyday sights are markedly changed.

Drucker is looking forward to the indoor version expected to come out this spring, emphasizing the impact EnChroma glasses have had on his daily, routine activities. “They’ve changed going to the farmer’s market, simple things like cooking,” he says. “I’m looking forward to my first rainbow.”

Li Zhou | | READ MORE

Li Zhou is the digital editorial intern for Smithsonian.com. She has previously written for The Boston Globe, PolicyMic and Interview Magazine.