 | |
 Glasses with special lenses which change color perception. | |
| Manufacturer | EnChroma |
|---|---|
| Website | https://enchroma.com/  |
EnChroma are a brand of color corrective lenses designed to address the 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. [1]
EnChroma lenses are designed, manufactured, marketed and distributed by EnChroma, inc. in Berkeley, California. EnChroma glasses were invented incidentally in 2002 by Donald McPherson while trying to develop lenses to protect and aid surgeons during laser operations. The company received a grant from the NIH in 2005 and the glasses were released to the public in 2012, with cheaper versions arriving in 2014. [2] In 2015, EnChroma teamed up with Valspar Paint in an advertising campaign titled "Color For All", which focused on the experience of trying on EnChroma glasses for the first time. This led new EnChroma owners to independently upload their own reaction videos, which eventually earned the ad campaign a number of marketing PRO awards by Chief Marketer, including best use of video and best use of social/viral marketing. [3]
The target users of the lenses have either deuteranomaly or protanomaly, both forms of red-green anomalous trichromacy, the most common forms of partial color blindness. The mechanism of red-green anomalous trichomacy sees the spectral sensitivity of the red- and green-sensitive cone opsins (L-opsin and M-opsin, respectively) shift towards each other, i.e. the L-opsin is shifted to shorter wavelengths (protanomaly) or the M-opsin is shifted to longer wavelengths (deuteranomaly). Either mechanism causes a larger overlap between the M- and L-opsin sensitivities, leading to a smaller color gamut, and the inability to differentiate colors along the red-green axis. [4] Common colors of confusion include blue vs. purple, yellow vs. neon green, grey vs. cyan vs. pink, red vs. orange vs. green vs. brown. [5] Neither dichromatic (protanopia or deuteranopia) users nor tritan users are targeted by EnChroma. [6]
As of December 2023, EnChroma markets SuperX lenses to non-colorblind users. [7]
EnChroma lenses are composed primarily of an optical notch filter that selectively filters wavelengths of light in the part of the spectrum where the M- and L-opsin sensitivities overlap, namely 530-560 nm, thereby removing light that excites both opsin types and decorrelating the signals between the M- and L-cones. [6] [8] EnChroma claims that the notch filter effectively re-separates the spectral sensitivities of the opsins, increasing the dynamic range of the red-green opponent process channel closer to that of color normal subjects, thereby correcting anomalous trichromacy (partial color blindness) and enabling users to distinguish colors they could not distinguish without the glasses. [9] [10] A number of patents have been awarded based on the technology. [8] [11] [12]
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." [13]
A 2022 study conducted at the University of Incarnate Word investigated the effects of EnChroma glasses on colorblind subjects (n=34). The study found that wearing EnChroma glasses led to significant improvements in color discrimination for both dichromats and anomalous trichromats. Additionally, the glasses were found to enhance participants' performance in various color vision tests. [14] Similarly, a 2020 study out of University of California, Davis (n=48) assessed the glasses' impact on color discrimination, color naming, and color preference tasks. The results indicated that wearing EnChroma glasses led to significant improvements in color discrimination and naming tasks for participants with mild to moderate red-green CVD. However, the glasses did not demonstrate the same level of effectiveness for those with severe CVD. [15] [lower-alpha 1]
A 2022 meta-analysis concluded that EnChroma lenses show no "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." [16]
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." [17]
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. [18] In a subsequent study, the EnChroma Cx-14 filters did not significantly influence the vision of colorblind subjects (n=10) and "improved the error score in only two subjects". [18]
The first study to incite popular skepticism of EnChroma [19] [20] [21] was a 2018 study published in Optics Express , where colorblind subjects (n=48 [lower-alpha 2] ) performed the Ishihara test, FM-100 test and a color naming test with and without EnChroma indoor lenses. The results showed no significant improvement to the performance on any of the color vision tests. [1] The study also claimed that only one participant noticed any difference in the colors in the test environment, when prompted, and the results "cast doubt on the real effectiveness these devices have on the color vision of observers with CVD." The study also showed that the mistakes made in the color naming test changed with the lenses on, suggesting that while it is possible for some subjects to freshly distinguish some colors with the glasses on, it comes at the expense of confusing others. [1] In an attempt to explain some of the emotional reaction used in EnChroma advertisements, the study's lead author 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." [19]
Color or colour is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, reflection, emission spectra and interference. For most humans, colors are perceived in the visible light spectrum with three types of cone cells (trichromacy). Other animals may have a different number of cone cell types or have eyes sensitive to different wavelength, such as bees that can distinguish ultraviolet, and thus have a different color sensitivity range. Animal perception of color originates from different light wavelength or spectral sensitivity in cone cell types, which is then processed by the brain.
Color blindness or color vision deficiency (CVD) is the decreased ability to see color or differences in color. The severity of color blindness ranges from mostly unnoticeable to full absence of color perception. Color blindness is usually an inherited problem or variation in the functionality of one or more of the three classes of cone cells in the retina, which mediate color vision. The most common form is caused by a genetic condition called congenital red–green color blindness, which affects up to 1 in 12 males (8%) and 1 in 200 females (0.5%). The condition is more prevalent in males, because the opsin genes responsible are located on the X chromosome. Rarer genetic conditions causing color blindness include congenital blue–yellow color blindness, blue cone monochromacy, and achromatopsia. Color blindness can also result from physical or chemical damage to the eye, the optic nerve, parts of the brain, or from medication toxicity. Color vision also naturally degrades in old age.
The visible spectrum is the band of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light. The optical spectrum is sometimes considered to be the same as the visible spectrum, but some authors define the term more broadly, to include the ultraviolet and infrared parts of the electromagnetic spectrum as well, known collectively as optical radiation.
Achromatopsia, also known as Rod monochromacy, is a medical syndrome that exhibits symptoms relating to five conditions, most notably monochromacy. Historically, the name referred to monochromacy in general, but now typically refers only to an autosomal recessive congenital color vision condition. The term is also used to describe cerebral achromatopsia, though monochromacy is usually the only common symptom. The conditions include: monochromatic color blindness, poor visual acuity, and day-blindness. The syndrome is also present in an incomplete form that exhibits milder symptoms, including residual color vision. Achromatopsia is estimated to affect 1 in 30,000 live births worldwide.
Tetrachromacy is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cell in the eye. Organisms with tetrachromacy are called tetrachromats.
Trichromacy or trichromatism is the possession of three independent channels for conveying color information, derived from the three different types of cone cells in the eye. Organisms with trichromacy are called trichromats.
Cone cells or cones are photoreceptor cells in the retinas of vertebrates' eyes. They respond differently to light of different wavelengths, and the combination of their responses is responsible for color vision. Cones function best in relatively bright light, called the photopic region, as opposed to rod cells, which work better in dim light, or the scotopic region. Cone cells are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. Conversely, they are absent from the optic disc, contributing to the blind spot. There are about six to seven million cones in a human eye, with the highest concentration being towards the macula.
In visual physiology, adaptation is the ability of the retina of the eye to adjust to various levels of light. Natural night vision, or scotopic vision, is the ability to see under low-light conditions. In humans, rod cells are exclusively responsible for night vision as cone cells are only able to function at higher illumination levels. Night vision is of lower quality than day vision because it is limited in resolution and colors cannot be discerned; only shades of gray are seen. In order for humans to transition from day to night vision they must undergo a dark adaptation period of up to two hours in which each eye adjusts from a high to a low luminescence "setting", increasing sensitivity hugely, by many orders of magnitude. This adaptation period is different between rod and cone cells and results from the regeneration of photopigments to increase retinal sensitivity. Light adaptation, in contrast, works very quickly, within seconds.
Dichromacy is the state of having two types of functioning photoreceptors, called cone cells, in the eyes. Organisms with dichromacy are called dichromats. Dichromats require only two primary colors to be able to represent their visible gamut. By comparison, trichromats need three primary colors, and tetrachromats need four. Likewise, every color in a dichromat's gamut can be evoked with monochromatic light. By comparison, every color in a trichromat's gamut can be evoked with a combination of monochromatic light and white light.
Monochromacy is the ability of organisms to perceive only light intensity without respect to spectral composition. Organisms with monochromacy lack color vision and can only see in shades of grey ranging from black to white. Organisms with monochromacy are called monochromats. Many mammals, such as cetaceans, the owl monkey and the Australian sea lion are monochromats. In humans, monochromacy is one among several other symptoms of severe inherited or acquired diseases, including achromatopsia or blue cone monochromacy, together affecting about 1 in 30,000 people.
OPN1LW is a gene on the X chromosome that encodes for long wave sensitive (LWS) opsin, or red cone photopigment. It is responsible for perception of visible light in the yellow-green range on the visible spectrum. The gene contains 6 exons with variability that induces shifts in the spectral range. OPN1LW is subject to homologous recombination with OPN1MW, as the two have very similar sequences. These recombinations can lead to various vision problems, such as red-green colourblindness and blue monochromacy. The protein encoded is a G-protein coupled receptor with embedded 11-cis-retinal, whose light excitation causes a cis-trans conformational change that begins the process of chemical signalling to the brain.
The evolution of color vision in primates is highly unusual compared to most eutherian mammals. A remote vertebrate ancestor of primates possessed tetrachromacy, but nocturnal, warm-blooded, mammalian ancestors lost two of four cones in the retina at the time of dinosaurs. Most teleost fish, reptiles and birds are therefore tetrachromatic while most mammals are strictly dichromats, the exceptions being some primates and marsupials, who are trichromats, and many marine mammals, who are monochromats.
The Farnsworth Lantern Test, or FALANT, is a color vision test originally developed specifically to screen sailors for tasks requiring color vision, such as identifying signal lights at night. It screens for red-green deficiencies, but not the much rarer blue color deficiency.
Gene therapy for color blindness is an experimental gene therapy of the human retina aiming to grant typical trichromatic color vision to individuals with congenital color blindness by introducing typical alleles for opsin genes. Animal testing for gene therapy began in 2007 with a 2009 breakthrough in squirrel monkeys suggesting an imminent gene therapy in humans. While the research into gene therapy for red-green colorblindness has lagged since then, successful human trials are ongoing for achromatopsia. Congenital color vision deficiency affects upwards of 200 million people in the world, which represents a large demand for this gene therapy.
Unique hue is a term used in perceptual psychology of color vision and generally applied to the purest hues of blue, green, yellow and red. The proponents of the opponent process theory believe that these hues cannot be described as a mixture of other hues, and are therefore pure, whereas all other hues are composite. The neural correlate of the unique hues are approximated by the extremes of the opponent channels in opponent process theory. In this context, unique hues are sometimes described as "psychological primaries" as they can be considered analogous to the primary colors of trichromatic color theory.
Color blindness, also known as color vision deficiency, is a symptom that concerns diminished color vision and the decreased ability to see or distinguish colors.
A color vision test is used for measuring color vision against a standard. These tests are most often used to diagnose color vision deficiencies, though several of the standards are designed to categorize normal color vision into sub-levels. With the large prevalence of color vision deficiencies and the wide range of professions that restrict hiring the colorblind for safety or aesthetic reasons, clinical color vision standards must be designed to be fast and simple to implement. Color vision standards for academic use trade speed and simplicity for accuracy and precision.
Color blind glasses or color correcting lenses are light filters, usually in the form of glasses or contact lenses, that attempt to alleviate color blindness, by bringing deficient color vision closer to normal color vision or to make certain color tasks easier to accomplish. Despite its viral status, the academic literature is generally skeptical of the efficacy of color correcting lenses.
Color tasks are tasks that involve the recognition of colors. Color tasks can be classified according to how the color is interpreted. Cole describes four categories of color tasks:
Congenital red–green color blindness is an inherited condition that is the root cause of the majority of cases of color blindness. It has no significant symptoms aside from its minor to moderate effect on color vision. It is caused by variation in the functionality of the red and/or green opsin proteins, which are the photosensitive pigment in the cone cells of the retina, which mediate color vision. Males are more likely to inherit red–green color blindness than females, because the genes for the relevant opsins are on the X chromosome. Screening for congenital red–green color blindness is typically performed with the Ishihara or similar color vision test. There is no cure for color blindness.