Physics:EnChroma

Short description: Eyeglasses marketed to color-blind people

EnChroma

Glasses with special lenses which change color perception.
Manufacturer	EnChroma

EnChroma lenses are specialized glasses designed to address symptoms of red-green color blindness. Studies have shown that these lenses can alter the perception of colors that were already perceived, but they do not restore normal color vision. Some claims made by the manufacturer have been subject to criticism and described as deceptive and marketing hype, because research shows that the lenses change color perception, but not in a way that improves overall color perception. Peer-reviewed studies and independent reviews conclude that the glasses "do not confer any improvement in the ... color blindness tests. Therefore, the glasses cannot improve scores in professional screening tests, contrary to what the company claims on its website." Emotional reactions in videos published by the manufacturer of people trying these glasses for the first time has been attributed to both fraud and to the honest emotional response by some people to the unexpected change in the perception of colors already visible to them.

Development and manufacturer claims

Donald McPherson invented EnChroma glasses by accident while trying to develop lenses to protect and aid surgeons during laser operations. The lenses focus on the most common color vision deficiency which is caused by the red and green retinal cone cells that, when responding to light, coincide. To eliminate the overlapping of the wavelengths of light, there is an optical material called a notch filter, which is capable of removing the exact wavelengths of light in the location where it overlaps, getting a simplified differentiation of colors. The manufacturer claims that the glasses block specific wavelengths to create a clearer separation of different color signals so that they can be better calculated by the brain, and that the separation of signals allows most people with color blindness to distinguish colors, but admits that the glasses will have little to no effect on the 20% of color blind people who have severe color impairment. A number of patents have been awarded based on the technology.

Independent analysis and reviews

Regarding the effectiveness of color correcting glasses in general, the American Optometric Association reports that "Using specially tinted eyeglasses ... can increase some people's ability to differentiate between colors, though nothing can make them truly see the deficient color."

A study in 2017 involving 23 males aged from 20 to 25 years with normal trichromatic color vision showed that EnChroma Cx-14 lens notches the blue and violet region of the visible spectrum. This induced participants with normal color vision to experience tritan defect when wearing the lens. In a subsequent study involving ten individuals with hereditary deficiencies (nine males and one female from age 19 to 52), the EnChroma Cx-14 filters did not significantly influence the vision of color blind subjects and "improved the error score in only two subjects".

A 2018 article published by Phys.org, "Scientists debunk the effectiveness of EnChroma glasses for colorblind people", reported on a study of EnChroma lenses by a peer-reviewed scientific journal Optics Express. The study "debunked the effectiveness of these glasses for color vision deficiency (CVD), proving that the EnChroma glasses don't make color blind people's vision comparable to that of people without color blindness." It went on to report that "a color-blind person using the EnChroma glasses will not perceive new colors, but rather sees the same colors in a different way. This makes it possible for some individuals using these glasses to distinguish some colors, but to the detriment of others, which will be now confused. Even though a color filter such as that used by the EnChroma glasses may change the appearance of colors, it will never make color vision more similar to a normal observer's vision." The researchers found the effect of using EnChroma glasses is similar to glasses where the use of color filters changes the user's perception and increases the contrast among the colors, such as those used for shooting or hunting, but determined that EnChroma glasses did not reveal any improvement in the Ishihara test and Farnsworth–Munsell 100 hue test. The report concluded that "the glasses specifically used in this study do not confer any improvement in the recognition or arrangement color blindness tests. Therefore, the glasses cannot improve scores in professional screening tests, contrary to what the company claims on its website.

A 2018 article from arsTechnica reported on a study performed at the University of Granada which said that "The particular wavelengths that are knocked out [by the glasses] now produce contrast that [users] didn't see before, so they see a dramatic difference in the world, but if they wore those glasses all the time and then took them off, they would have that same reaction." It reported that none of the Granada subjects reported any improvement to the colors around them when wearing the glasses. Thus, it is "possible for some individuals using these glasses to distinguish some colors, but to the detriment of others, which will now be confused", concluding that "EnChroma glasses won’t fix your color blindness" and that "users aren't really seeing new colors, just the same colors in a different way". The article also states that "There have always been roughly equal measures of enthusiasm and skepticism about the effectiveness of EnChroma glasses, and firsthand accounts vary from 'meh' to life-changing revelations. That may be because color perception is (a) inherently subjective, and (b) there are many different types of color blindness, and EnChroma's product will interact with them in complicated ways."

A 2019 New York Magazine review included an interview of Luis Gómez Robledo, professor in the Department of Optics at the University of Granada in Spain. The article reports that Robledo and colleagues conducted a study published in October 2018, which included 48 color-blind volunteers. The study results concluded that "EnChroma glasses don’t cure color-blindness" and found that "none of the participants noticed any improvement to the colors of their surroundings when looking through the glasses except for one female patient." Robledo also found that "cheap high-contrast hunting glasses" had a similar effect on color perception to that of wearing EnChromas. In an attempt to explain some of the emotional reaction used in enChroma advertisements, Robledo stated that "The use of a colored filter may change the appearance of colors, but will never make color vision more similar to a normal observer’s vision. It’s like turning up the contrast on a TV, which for some people can be startling enough to trigger an emotional reaction."

A 2021 article published by the American Academy of Ophthalmology reported that color blindness glasses "change what the people who wear them see, enhancing the distinction between red and green ... but the experience will vary widely among individuals, and these glasses don’t give people a true equivalent of natural color vision." The AAO also says that "the positive effects of the glasses last only as long as they are being worn." and that the enChroma glasses "don't in any way modify a person's photoreceptors, optic nerves or visual cortex to fix colorblindness."

A 2022 article published in Health Science Reports, "Color vision devices for color vision deficiency patients: A systematic review and meta-analysis" concluded that "commercially available color vision devices, such as EnChroma Glasses, Chromagen filters, and EnChroma Cx-14 do not provide clinically significant evidence that subjective color perception has improved. As a result, recommending these color vision devices to the CVD population may not prove high beneficial/be counterproductive. However, only a few color shades can be perceived differently."