Wed. Sep 28th, 2022
Guy enjoying winter sports in sunglasses is happy.
enlarge / EnChroma glasses have always had both skeptics and true believers. Who’s right? It’s complicated.

The acclaimed EnChroma glasses don’t help colorblind users see new colors; they allow colorblind people to see the same colors differently, according to a new study published in Optics Express by scientists from the Spanish University of Granada. The scientists compare the effect with the colored glasses that hunters often use to increase the contrast in their environment, so that they can better pick up certain visual stimuli.

EnChroma makes glasses designed to help with a specific form of color blindness, one in which a hybrid of red and green detecting receptors confuses the differences between colors. The receptors work by blocking the wavelengths to which the hybrids are most sensitive, but they do nothing for other forms of color blindness.

So the new results come as no surprise to Jay Neitz, a color vision expert at the University of Washington, who has long been skeptical of what the glasses actually accomplish. “You can’t add colors by taking away some wavelengths [of light]that’s all the glasses do,” he says.

But Andrew Schmeder, CEO of EnChroma, disagrees with the study’s conclusions. “The University of Granada research is based on an erroneous assumption about how color vision screening tests work, because they cannot prove or disprove whether color vision improves or not,” he said in a statement to Ars Technica. “EnChroma does not approve the use of our glasses in such color blindness screening tests.”

There’s always been roughly equal degrees of enthusiasm and skepticism about the effectiveness of EnChroma goggles, and firsthand stories range from “meh” to life-changing revelations. That may be because color perception (a) is inherently subjective, and (b) there are many different types of color blindness, and EnChroma’s product will deal with that in complicated ways.

Journalist Oliver Morrison, for example, was unimpressed. Sign up The Atlantic Ocean in 2015, he said, “It’s not like they were any worse than regular sunglasses — there was a way certain things showed up — but not the way it felt like it was advertised.”

Meanwhile, former Ars reporter Nick Veronin, who is moderately colorblind, wrote about his experience with the glasses in 2016. He wasn’t blown away when he put them on, unlike many of the people in the company’s testimonial videos. But as he drove around, he saw brilliant greens and purples, and he decided the glasses helped improve his color perception a bit.

Many types of color blindness

Part of the discrepancy no doubt stems from a fundamental misunderstanding about color blindness. We usually have three types of cones in our retina that are sensitive to specific colors in the electromagnetic spectrum: blue, green and red. Technically, each type of cone detects either short (S), medium (M), or long (L) wavelengths of light. The brain processes the information gathered by the three types of cone cells to give us our perception of color. There is a natural degree of overlap between cone cells, but in general, each type responds most strongly to a narrow range of wavelengths.

However, certain genetic mutations can mess up this neat arrangement in various ways. About eight percent of men in the US (one in twelve) have some form of red/green color blindness, according to Neitz. This is by far the most common form. For example, “abnormal trichromatics” are those people whose brains still get information from all three photoreceptors, but the M or L cones have shifted their wavelength sensitivities just enough to make it more difficult to distinguish colors in the red-green dimension. . How severe the condition is depends on how much the wavelength sensitivity is shifted.

“Pink can appear gray. Purple and blue are often confused.”

Veronin falls into this category. The EnChroma online test determined that he was a “moderate deutan.” “People like me may have trouble distinguishing between green and brown, red and brown, and yellow and orange,” he wrote. “Pink can appear gray, purple and blue can be mixed up a lot, and the green light in a traffic light may seem like nothing more than bright white.”

But his condition is not so serious as to be debilitating. First diagnosed at age six, Veronin developed coping tricks over the following decades, such as checking the color of a particular item of clothing with the store clerk before purchasing it.

The EnChroma glasses are designed to correct certain types of color vision defects (such as Veronin’s mild red/green color blindness) by blocking certain wavelengths of light. “Essentially, we’re removing certain wavelengths of light that correspond to the region with the most overlap,” Schmeder told Gizmodo in 2016. “By doing this, we’re actually creating more separation between those two information channels.”

A more serious form of color blindness is called dichromatism. People with certain genetic defects cannot make L or M photoreceptors, so they only have two working photoreceptors instead of three. Even the most severely affected aberrant trichromat has color vision that is 10 times better than a dichromat, according to Neitz. “They live in a world where there is only black and white, gray and then only two colors: blue and yellow,” he says. “There’s very little sense of red or green. They can’t tell the difference between a well-done steak or a completely rare one — it’s all the same gray color to them.”

Eight classic Ishihara maps for testing color blindness, circa 1959.
enlarge / Eight classic Ishihara maps for testing color blindness, circa 1959.

SSPL/Getty Images

Those are the people who are really suffering, and they are the ones who need a solution the most. Unfortunately, the EnChroma glasses do not help people who suffer from this form of color blindness. That was Morrison’s experience; he is completely lacking in red-sensitive pigments, one of the most severe forms of color blindness. For him, the glasses “just accentuated the difference between the really bright billboards and the dull hues of streets and clothes,” he wrote. He speculated that was because “I didn’t see enough colors for the glasses to effectively amplify them.”

That’s why EnChroma doesn’t claim that its glasses will help all forms of color blindness or that the glasses are any form of “cure”. The company prefers to describe its glasses as an aid to those, like Veronin, who are mild to moderately aberrant trichromats: the glasses should help them better distinguish colors in the red/green dimension.

Putting it to the test

As Gizmodo reported, EnChroma mainly relies on subjective user feedback to judge the efficiency of its glasses in improving color perception. But the company did conduct some clinical trials using a test known as the D15, which requires subjects to arrange 15 colored circles in rainbow (i.e., chromatic) order.

The results were mixed: some EnChroma subjects showed more improvement than others, and the improvement did not seem to correlate with color blindness severity. According to Neitz, colored filters (like the EnChroma glasses) can improve the relative brightness of the chips, providing a useful contextual clue. The D15 is therefore not the best objective measure.

The researchers at the University of Granada used the classic Ishihara test to evaluate recognition and the Fansworth-Munsell 100-hue test to evaluate ranking. They also evaluated subjective color naming based on the X-Rite color chart. The researchers also studied the changes in color rendering by simulating different observers with the spectral transmission of the lenses.

“Although a color filter can change the appearance of colors, color vision will never resemble the view of a normal observer again.”

So what did they find? Wearing the glasses did not help any of the participants perform better on the two types of color blindness tests used in the study. That’s consistent with EnChroma’s claims on its website (and Schmeder’s statement to Ars Technica), as well as Veronin’s first-hand experience. So if you’re hoping to use the glasses as a cheater to pass a screening test to become a TSA agent or police officer, forget it.

When the subjects from Granada were asked to look around and subjectively rate their color perception, none of the subjects reported any improvement in the colors around them when wearing the glasses. So it’s possible that some people use these glasses to distinguish some colors, but at the expense of others, which will now be confused,” the authors concluded. “Although a color filter like the one used by the EnChroma glasses can change the appearance of colors, color vision will never again resemble the vision of a normal observer.”

The research team from the University of Granada poses with EnChroma glasses.
enlarge / The research team from the University of Granada poses with EnChroma glasses.

University of Granada

That is also Neitz’s assessment. “The specific wavelengths that are turned off [by the glasses] now produce contrast that [users] I haven’t seen them before, so they see a dramatic difference in the world,” he says. “But if they wore those glasses all the time and then took them off, they’d have the same reaction.”

When Morrison lent the glasses to a non-colorblind friend, the friend even noticed a marked improvement in her color perception. That said, “I’ve seen data showing there is some improvement for aberrant trichromatic, so you can’t really say it doesn’t work at all,” Neitz says.

Neitz believes EnChroma is genuine in its desire to help people with color vision disorders and that the company’s founders sincerely believe the glasses are effective. “A lot of the problem has to do with deep misunderstandings about the nature of color blindness by the general public, the people at EnChroma, and color blind people themselves,” he says. “If everyone better understood the basic facts of color blindness, there would be no controversy over whether the glasses are effective or not.”

EnChroma’s full statement is below:

EnChroma has invented an innovative product that changes our understanding of how people with color blindness see the world. It is not uncommon for a new technology to be received with skepticism – this is a natural part of scientific discourse. Unfortunately, the research from the University of Granada is based on an erroneous assumption about how color vision screening tests work, as they cannot prove or disprove whether color vision improves or not. EnChroma does not approve the use of our glasses in such color blindness screening tests.

EnChroma is convinced that our glasses are effective and provide real benefits for the color vision of the colorblind. We encourage researchers interested in studying EnChroma to contact us to receive sample glasses and a copy of our research guidelines.

DOI: Optics Express2018. 10.1364/OE.26.028693 (About DOIs).

By akfire1

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