As with most eureka moments, Don McPherson’s came to him in an unexpected way as he was playing Frisbee in Santa Cruz, California. His friend asked to borrow his sunglasses and for the first time in his life was able to distinguish bright orange cones from the green grass.
McPherson, a doctor of glass science based in Berkeley, California, made the eyewear for physicians to help them tell blood from tissue during laser surgery. He wears the glasses himself because they protect from ultraviolet radiation, McPherson told Not Impossible Now in an email, and they enhance the contrast in colors, which he enjoys.
After his friend borrowed his glasses at the Frisbee game, McPherson realized he could reach out to the 300 million people who are colorblind. One in 12 men and one in 233 women have color vision deficiency. About 80 percent can be helped by the glasses, McPherson estimates.
For children, colorblindness can be especially difficult. Only 11 states test for it in school, McPherson says, and students who are colorblind often fall behind and are misdiagnosed as having learning disabilities. Adults who suffer from color vision deficiency face hurdles at work, such as color-coded information. And all those who are colorblind miss out on the fullness of everyday life, McPherson says.
“If you do any activity and try to imagine life without color, or at least without the richness, you can begin to see how it would affect your life if you were CVD,” McPherson said. “Sporting events, gardening, hiking, shopping, dressing, dining, etc. The list is quite long and wide.”
Case in point: EnChroma teamed up with paint manufacturer Valspar on a documentary called “Color for the Colorblind,” which captures the emotional reaction four colorblind people have after experiencing color for the first time using the glasses. The video has garnered more than 1.5 million views on YouTube so far.
McPherson received three grants from the National Institutes of Health to research his sunglasses and studied them for 10 years. In 2012, he and colleagues Tony Dykes and Andrew Schmeder founded EnChroma, Inc. and started selling sunglasses.
The first version of the eyewear was made out of glass, Schmeder said in an email to Not Impossible Now. Glass is considered a premium lens material and has the best optical quality, Schmeder says, but it has been almost completely phased out.
EnChroma switched over to plastic last December. Its prescription lenses are polycarbonate, which is recommended by eye care professionals for children, who are more prone to accidents, Schmeder said.
EnChroma announced last week that they are offering eyewear for indoor as well as outdoor use. They’re available online at EnChroma.com, come in sporty frames and start at $324.95. The company is in the process of making them available through eye care professionals.
As part of the work designing the glasses, Schmeder, a mathematician, created a model of color vision in the human eye. As he explains it, the eye works like a digital camera. The surface of the retina is densely packed with retinal cone cells, which respond to red, green and blue light. There are six to seven million cones, which are like the mega-pixels in a color camera.
Red and green cone cells overlap normally, but when they overlap too far, the eye doesn’t see colors correctly. There are other less common reasons for color blindness, such as a faulty passageway from the cone to the brain.
Layers of nerve cells that perform the equivalent of mathematical calculations are attached to the retinal cone cells. They compute color and brightness. To simulate this whole process in the computer, Schmeder uses a mathematical model of the basic elements of color vision. His database contains thousands of colors as diverse as leaves in various stages of growth. For every hue, he and his team calculate how much is absorbed by the retinal cone cells. So far, this is standard science, Schmeder says.
They take it several steps further, however, modifying the model to mirror different types of color vision deficiency, such as red-green colorblindness. EnChroma researchers use the model to predict how different filters will perform. Schmeder says they discovered that, given any set of conditions, finding the optimal lens for any correctible colorblindness can be represented in a mathematical format known as a linear program.
Ron Strickland, 72, of Bedford, Massachusetts, told Not Impossible Now that he was in awe the first time he tried EnChroma sunglasses. Strickland has been climbing scenic trails around the country for decades, is the author of nine books on hiking and founded the 1,200-mile Pacific Northwest National Scenic Trail. Grass had always looked a dull brown and red was washed out too, Strickland said. With the glasses, the grass looked vivid green and the autumn leaves were a brilliant red. He saw a bright green sign he had never seen before.
“I felt great surprise because I was already 69 or 70 and I thought I knew the way things looked,” Strickland said, “but all of a sudden I was perceiving things in quite a different way. It was a sense of surprise and wonder.”
When he’s home, Strickland is often struck by rich color, too.
“If I see a bright red car go by I’m astonished,” Strickland said. “It looks so unexpected.”
Learn more about EnChroma at their website.
Top screenshot courtesy of Valspar’s YouTube channel