Glasses Help Color-Blind See Trees Of Green, Red Roses, Too

By Stephanie Lee
San Francisco Chronicle.

Decorating the house has always been challenging for Sheila Carter. Like other color-blind people, she limits her wardrobe to a few bold hues that can be easily mixed and matched, like blue and black.

But a new pair of glasses she recently started wearing, she said, has changed her worldview.

“Sunsets are amazing,” said Carter, 60, a group trip coordinator in Georgetown, Texas. “I always knew you could see the gold ball of the sun. I didn’t know gold streaks ran out horizontally from the sun. I didn’t realize the whole landscape took on a different hue.”

Carter owns high-tech eyewear made by EnChroma, a Berkeley startup that wants to help people with color deficiency see the full spectrum of the rainbow.

Carter is among an estimated 32 million Americans who are color-blind, either from birth or as a result of some condition, like head trauma. The condition is most prevalent among people of Northern European descent, affecting 8 percent of men and 0.5 percent of women.

EnChroma makes color-enhancing sunglasses for the vast majority of such people, who have trouble seeing red or green due to a genetic defect. The company has sold more than 1,000 pairs in two years. Last month, it introduced glasses with polycarbonate lenses for children, athletes and prescription- and nonprescription-wearers at prices ranging from $325 to $450.

“There are certain activities they do which they don’t feel comfortable doing, like driving,” said Don McPherson, EnChroma’s vice president of products, of his consumers. “Even trivial things like detecting a red curb, so you can’t park there.”

He added, “Ideally, we would want to give them a product that restored their ability to identify the color and the quickness with which they did that to normal.”

Cones in eye
At the back of the eye, there are three types of color-sensing cells, called cones, that respond to different parts of the spectrum of light: blue, green and red. The three overlap somewhat, but in the case of a red-green deficiency, the cones’ responses to green and red overlap too much. That causes the red and green cones to send the same, or almost the same, information to the brain, which then has difficulty discriminating between the colors. This confusion also leads the brain to mix up blended, muted colors that contain red or green, such as purple.

The image at left shows how an individual with color blindness sees poppies; on the right, the same poppies are seen using EnChroma’s color blindness correcting glasses.

A growing market of tools and programs wants to make life more colorful. There are special contact lenses, as well as apps that can identify colors by name or numerical codes so people can “see” what colors appear on a website. O2Amp makes tinted-lens glasses that are intended to give doctors clearer views of human anatomy, but have the unintended side effect, the company says, of helping the viewer distinguish between red and green.

EnChroma says that unlike conventionally tinted lenses that can only enhance one color, its smart glasses enhance the three primary colors simultaneously. This technology grew out of research initially funded by the National Institutes of Health.
Cutting overlap

The proprietary lens contains a filter that blocks a portion of the spectrum where the overlap between the two cones occurs and restores the separation between them. “It’s essentially taking out that stuff that’s confusing the signal,” said Andy Schmeder, vice president of technology.

EnChroma, an angel-backed startup founded in 2010, started out with lenses made with a glass substrate. It hopes to expand its audience with its new, polycarbonate-based frames, which are more durable, can hold up under greater impact and come in styles ranging from aviator to athletic wraparounds. Young children can especially benefit, the company says, because their relatively malleable brains can learn to better distinguish between hues.

The image on the left shows how an individual with color blindness sees; the image on the right shows the same scene using EnChroma’s color blindness correcting glasses.

For now, these shades aren’t covered by insurance, with the possible exception of those with prescriptions. They are also meant only for use in bright sunlight, although EnChroma is developing versions that can work indoors and even underwater. In addition, the glasses may not work for people with severe red-green deficiency, about 20 percent of the color-blind population.

For the most part, Carter said she is able to live a normal life. But there are unexpected downsides: When her daughter was in high school, she would dye her hair and Carter never noticed it. With the new glasses, that’s no longer the case.

“I have red-headed children,” she said, “and I have never really understood how beautiful their hair is.”

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