This survey was run in conjunction with my post on color vision and the implications EnChroma glasses have on our understanding of what color is. If you are interested in learning more about how color vision works, why some people see color differently, and how EnChroma glasses work to fix this, check out that post.

I am in no way affiliated with EnChroma Inc. They did however aid me with methodology and sharing the survey.
I would also like to point out I have never done survey based research nor is vision a field I am familiar with. All criticism and feedback is warmly welcomed.

 

Color vision, color blindness, and Enchroma’s efficacy – An internet sourced survey on what color means

Dr. Blake Porter, University of Otago

Introduction

“But to determine… by what modes or actions light produceth in our minds the phantasms of colours is not so easie. And I shall not mingle conjectures with certainties.” – Isaac Newton, on discovering white light contained the rainbow, in “New Theory About Light and Colour”, 1671

My original post on EnChroma glasses and this survey was driven by my curiosity with color; what color is, how the brain creates it, and the unique experiment EnChroma has set up for people interested in such mysteries. Color perception has been something philosophers at least as far back as Aristotle have been thinking about. Newton’s famous prism experiment demonstrated that light is the delivery mechanism of color stimuli to our eyes just as jiggling particles deliver heat to our skin. However, we know from case reports, like “The case of the colorblind painter” (PDF) in the late Oliver Sack’s “An Anthropologist on Mars“, that damage to a specific brain region of the visual cortex, V4, will eliminate a person’s color perception and they will exist in a black and white world. People too without the specialized cells in their eyes which detect short, medium, and long wavelengths of light cannot see color. Outside the brain our genes build and our experiences craft, there exists no colors; just varying wavelengths of electromagnetic radiation whizzing around. However, with the proper hardware in the retina, a network of carefully laid cabling from the eyes can provide the brain with information about a tiny bit of this electromagnetic radiation. And, quite remarkably and still mysteriously, the brain converts these wavelength signaled 1’s and 0’s into the experience many of us know of as color. Yet, there exists a substantial group of us humans who have retinal hardware that is a slightly tweaked such that, rather than detecting three distinct wavelengths of light, they can only detect sort of two and half. Most often it is the case their cells instead respond to short, longish-medium, and long wavelengths (or short, medium, and mediumish-long) and resultantly these people have trouble seeing the middle wavelength light, or as most of us intimately know it, green. With tweaked hardware, the signals sent from the retina to the brain is muddled up and noisey, akin to a radio station with static. However, scientists and innovators set out to solve this problem and provide a solution to bring back colors to those who cannot fully see the rainbow. EnChroma created a unique optical filter which filters out the wavelengths of light that cause the tweaked retinal neurons to send the most noisey signals to the brain. This in turn allows some of those with color blindness to experience colors they did not have a relationship with previously, but were aware of due to language. YouTube videos of people trying on the glasses for the first time have been gaining viral popularity. What is most striking to me is people instantly see new colors once they put on the EnChroma glasses. No need for their brains to go through extensive rewiring to set up new circuits over the course of months or weeks or even days; it is instantaneous. The immense emotional reaction nearly all people have trying on the glasses is captivating and demonstrates just how profound of an impact colors can have to someone who has never experienced them fully before. Just imagine if we had glasses to see beyond our tiny visible range!

Thus I was extremely curious as to what was going on in their brains as these new colors painted their consciousness. How is it possible that someone who has never seen much of green before had the circuits [still] in place to instantly processes new greens and create an accurately colored forest canopy? More interesting still, for colors people had never seen any form of, which is often purples, how did their brains just come up with purple? Was it only because they had a word for purple? Or are our visual processing hardware able to handle brand new inputs? Unfortunately, I cannot employ my usual investigation method of electrode implantation and brain recordings but the next best thing was a survey. How long did it really take for EnChroma glasses to work? Did colors keep changing after people first tried them on? Also, how far would people go to be able to access sensory perceptions they don’t currently posses? These questions and many more were pitched to the internet and the findings and my musings can be found below.

 

Demographics and general results for color vision, philosophy and attitudes

Data collection methods

As well as being linked to in my post, the Google powered survey was also posted to two subreddits, r/colorblind and r/samplesize. r/colorblind was immensely helpful with getting respondents for the survey, receiving feedback on the survey, and early renditions of graphs so that they are color blind friendly. r/samplesize was utilized to obtain more “normal” color vision responses. I would also like to thank the EnChroma team for posting the survey on their social media channels; this helped immensely with getting EnChroma user responses and their experiences for the survey. I also reached out to people on YouTube who posted videos of themselves or their loved ones trying out EnChroma glasses. In total, 406 wonderful people responded to the survey. As you may expect with internet polling, the vast majority of respondents were males in their twenties and a majority (66%) had at least some university education or more. Sadly, not a single medical doctor took the survey.

 

Do you think color is…

I regret not asking people if they had read my article or not, as to see if it influenced their views on color, but either way 249 (61%) people correctly think color is created in the brain. Furthermore, 158 (39%) of respondents think that color exists outside the brain; I do hope they see my post and possibly change their minds on this issue. However, data is never so clear cut as any scientist would know. Despite the convenient percentages, reports were not binary; 72 (17%) people think that color is both created in the brain and exists in the outside world. An interesting but not entirely illogical stance. Coincidentally, 72 other people do not think color is made in the brain nor think that it exists outside the brain. A contradiction I am not sure how to interpret as color would therefore exists no where, as far as I can see. Perhaps It was not clear form how I asked the question or formatted the answers.

Moving on, 94 (23%) presumed humans think color is universal across all humans. Furthermore, 139 (34%) think it is relative to someone’s environment, 109 (27%) relative to someone’ culture, and a mere 98 (24%) relative to someone’s language. Again, I wish I had asked if people had read my article, or listened to Radiolab’s Colors episode, or read the works of the late Oliver Sacks to gauge their exposure to the evidence that color may be shaped largely by language.

 

 

Would you _______ that let you see UV and infrared light?

Not surprisingly, most people were unsure or adverse to getting invasive surgery to see ultraviolet and infrared light, just 84 (21%) people wanted these super senses. The attitude quickly shifts though if they only need to pop in contact lenses, with 241 (53%) persons electing to use them. Only 330 (81%) people would wear glasses that would let them see UV and IR light. I had assumed this would be much closer to 100% as there is little cost to putting glasses on your face. It is worth noting only 18 (4%) people would in “no way” wear the UV/IR glasses, the remaining 58 (14%) were unsure. This question was mainly to gauge, subtly I hope, the cost people would incur to expand their perception of light. Many people with color blindess wish to have EnChroma glasses, if the tech suits their type of color blindness, but would people be willing to use say EnChroma contacts to expand the wavelengths of light they can perceive? Would they go through surgery to see more? This is of course not science fiction nor even far off. Scientists have already given monkey’s full, human like tri-chromatic color vision with gene therapy. It is not difficult to imagine adopting an insect UV sensor and snake IR sensor and putting them into human eyes with a similar method to that of the monkey experiment. Are people willing to go to lengths such as invasive surgery to expand their senses? It appears, from this small survey at least, about 20% of people would be willing to incur such costs. A funny aside, I got a message asking if I was working for the government because I was “obsessed” with this question since, naturally, I had to be working on creating super soldiers.

 

 

Color blindness and chromosomes

Of the 406 total respondents, 189 (~47%) reported some form of color blindness; quite an even distribution for making comparisons. As explained in my post, the sex of a person can heavily influence their probability of color blindness due to mutations on the male Y chromosome. Thus, rather than asking only for gender, I asked for what people’s chromosomes were. A small percentage of people (3%) did not respond, but overall 263 (65%) of respondents were XY (traditional male) and 132 (32%) were XX (traditional female). Due to attempting to have an equal number of “normal” and color blind respondents, there are many more people with color blindness than you would expect in the general population which is usually around 8% of XY and 0.5% of XX. However, the trend of more males having color blindness than females was represented with 154 (57%) XY and 33 (25%) XX respondents being color blind.

Color blind respondents

What term do you prefer?

I chose my terminology throughout this article on purpose due to 63 (33%) people with color blindness reporting they prefer the term “Color Blind”. 51 (27%) preferred “Color Deficient” while most just did not care either way, 66 (35%). Nine people provided other terms, such as “Color Confused”, “Color Vision Deficient (CVD)”, “Color Impaired”, “chromatically challenged”, or quite simply “unable to differentiate color.”

Color blindness type, cause, and length

Terminology clarification: If someone has difficulty seeing a color, the condition ends in “-onamly” indicating their vision for that color is anomalous, or different from normal but not lost. If someone can not see a color at all, often because they entirely lack the cells that respond to that wavelength of light, the condition has an -opia suffix meaning optical deficit. The two most common types of color blindness are green (Deuteranomaly/Deuteranopia) and red (Protanomaly/Protanopia) with green deficit people, or Deutans, being the most common. Blue color blindness (Tritanomaly/Tritanopia) is very rare. Finally, if someone has difficulty seeing all colors equally, they are Achromatic. So Deutan = green effected, Protan = red effected, Tritan = blue effected, and Achromatic = all colors effected.

Consistent with the epidemiological data, most (77%) color blind respondents were a type of Deutan (25% Deuteranomaly / 22% Deuteranopia) or Protan (16% Protanomaly / 13% Protanopia). There was a few Tritan type ( 4% Tritanomaly / 1% Tritanopia) and Achromatics (1% Achromanomaly / 3% Achromatopsia). Interestingly, 28 (15%) people were not sure on what type of color blindness they had. I have seen quite a few posts in r/colorblind about people having difficulty figuring out what exact color blindness they have so I am not too surprised with this result.

 

 

Nearly all (95%) color blind respondents were color blind for genetic reasons. There was one person for each other reason; type 1 diabetes, trauma to the brain, trauma to the eye, disease related, and age related. Five people were not sure of their cause which is a bit odd. As you may expect, those same 179 people that made up the genetic causality have been color blind since birth. Three people have been color blind for more than 10 years and another three for 5 years, One person for more than a year while one other has been for less than a year. Two people did not respond.

The impact of color blindness on the lives of those with it

When asked, “Do you feel as though your color blindness negatively affects your life?” the average response was a 4.5 (median: 4) with 1 being “not at all” and a 10 being “severely affects.” Three has the highest response rate with 22%. It seems as though people feel there is some negative effect color blindness poses on their lives but, thankfully, it is not a large one.

 

 

Almost, but not quite, does a bimodal distribution emerge from the responses to,  “Do you feel as though your color blindness limits your employment opportunities?” The average response of 4.6 (median: 4) is again close to the mid line. However, many people, 37 (20%) reported a 1; that their color blindness does “not at all” limit their employment. The responses gradually fall away from 1 but then there is a second bump (24%) around 7 and 8. A response of a 10 meant “severely affect” their employment changes.

 

 

I looked a bit more into this discrepancy with a hunch that men tend to pursue jobs that require good color vision, such a firefighter (4% women) or police officer (5-15% women) more than women do. And I was completely wrong. There was no significant difference (Chi Square, p = 0.58) between men and women and their attitudes towards their color blindness limiting their employment opportunities, about 60% of both genders responded with a value less than or equal to 5, 40% a 6 or greater. So much for my sexist assumption.

The greatest number of people, 77 (41%), would not have pursued a different professions if they did not have color blindness. This was followed by 61 (32%) being unsure and 50 (26%) indicating they would have pursued a different profession is they were not color blind.

 

 

Unfortunately, 54% of color blind respondents have avoided a hobby or activity due to their color blindness. A smaller percent, 13%, have avoided these things on occasion. 33% however “never” let their color blindness limit their hobbies or activities.

 

 

Seeing the world with color blindness

I was interested in what colors people with color blindness had the most difficulty discriminating. Not surprisingly (remember Deutans, or green deficient, are most prevalent) green was the most difficult color to discriminate. Interestingly, red was not the second hardest, rather, it was purple!

 

 

Purple, as well as pink to a lesser degree, is quite a tricky color for our brains and is actually created by our brains when we see, well rather, do not see, green. That is to say when red cones activate and blue cones activate and green cones do not activate, we see purple. This is known as additive color mixing and it is how pixels on our computers work to produce all the colors we see. I cover all of this in my other post in more detail, but if you do not have normally functioning green responsive cells (Deutans) or if you do no have functioning red responsive cells (Protan), your brain cannot properly mix blue and red since the longer wavelength sensitive cells, green and red, will both be erroneously activated by red light. Thus, rather than purple light stimulating red and blue cones without activating the green cones, purple stimulates all three cones in Deutans and Protans. This in turn makes purple nearly impossible to derive for Deutans and Protans and our survey demonstrates just that. The third most difficult was indeed red.

Rather than discriminating, I next asked if there was any colors that folks with color blindness could not see at all. Consistent with the above hypothesis on purple, 45 people (24%) with color blindness cannot see purple at all. This comes with even more surprise by the margin it has on green, which 22 (12%) cannot see. Therefore it may indeed be very hard for people with color blindness to effectively construct purple due to its chromatically complex make up from precise wave length signaling.

 

 

I think it is important to note I left this question open for response as well. Many people wrote in that they could not see pastels or more nuanced colors, like teal, cyan, peach, or indigo. Many people reported that there were only certain shades of green that they could not see. It also did not occur to me, but many people pointed out, to varying degrees of politeness, that they could not possibly know exactly what colors they could not see. Fair point.

How annoying is it to be asked “What color is this?”

For a bit of comic relief (but I also was genuinely curious) I asked the wonderful people with color blindness how annoying it was to be asked, “Hey! What color is this? What color is this?” ad infinitum. A response of 1 indicated they were not bothered while a 10 meant they wanted to punch pestering people in the face. As you may expect, most people find this annoying, with a mean response of 6.3 (median: 7). So stop asking people with color blindness what they see.

 

 

Do EnChroma glasses actually work? How effective are they? Color blind respondents with EnChroma glasses

General questions

It was pretty difficult finding respondents who had EnChroma glasses but I did manage to get 42 respondents with EnChroma glasses, an alright sample size. Most people (60%) simply ordered the glasses for themselves but, as you may have inferred from watching the EnChroma reaction videos, 14% of people got them from their spouse followed by 7% for both family member or parent. One person had a great friend who got them the glasses. Some people had purchased more than one lens tint type; EnChroma has varying degrees of tint that range from one for indoor use, a dark tint sun glass, and a tint in between. CX-14 are the conventional sun glass tint and were the most popular with 18 people having them. The medium CX-25’s were second most popular with 12 pairs, and the indoor CX-65’s numbered only 3. This next result may not come as much as a surprise then, 86% of people (36) tried on EnChromas outside for their first time. 10% inside, and 5% both. There was also a pretty equal range of how long people had the EnChroma glasses for, from less than a week to more than 6 months. Most people (67%) wear their glasses all the time, 14% on occasion, and 19% depends on the situation.

How well do EnChroma glasses work? Did they change your life? Did they increase the quality of your life?

A whoping 90% of EnChroma users say they would recommend the glasses to others with color blindness. This does not come as much of a surprised because 55% reported EnChroma lenses changed their life and another 36% reported they “somewhat” changed their lives. 10% reported they did not. Furthermore, when asked if they increased their quality of life, 64% said “yes”, 31% “somewhat”, and only 5% “no”. This is great news as it seems like EnChroma glasses have a very positive benefit on the lives of those who wear them.

Did colors continue to change from the first time you tried on the glasses? If so, what colors changed? By how much?

Briefly and simply, neuroplasticity is the ability for brain cells to change their connections with other brain cells. However, this processes takes time, from seconds for basic changes to weeks and months for long term changes. For example, if you were to start brushing your teeth every night with your non-dominate hand and got an MRI once a week, after a month or so you could see your brain physically change as connections are re-wired and grow more robust. If you had electrodes implanted in your brain you could see smaller, but drastic changes in just seconds.

When asked what single color range changed the most, results were similar with green (40%), pink (19%), purple (17%), and red (12%). A vast range of greens requires a supporting symphony from the short and long cones for the medium cone conductor. However it is often the case of those with color blindness that the green is too meek or the red is too loud. EnChroma glasses filters out the trouble makers so more nuanced greens can be perceived. This is likely why the greens are most effected.

 

 

I was very interested in the time course of color vision development with EnChroma glasses as many of the videos seemed to show people instantly being able to discriminate colors better. Large scale rewiring of the brain would take much longer than seconds, but the videos do indeed show changes are nearly instant. There was a pretty even distribution of responses to this question. The majority (36%) did report colors “somewhat” continued to change from the first time they tried on the glasses. This was followed by 21% reporting “a little”, 26% “drastically”, and 17% “only some colors.”

 

 

I realize now I did not leave an option for “not at all” and perhaps some people indicating “a little” would have chosen “not at all”. Furthermore, it was reported most often (29%) that green changed after the first time of trying on the glasses, followed by red (21%), purple (19%), and pink (17%). It would have been convenient for the purple processing theory if purple changed most often as people’s brains improved at mixing blues with the new and improved greens, but evidence is rarely so clear cut.

 

 

Neuroplasticity is a function of age. That is to say younger people’s brains can change more easily than their older counterparts. Children aged 0-3 have extremely plastic brains and nearly all (~95%) of our brains major wiring is done during these early years. I looked to see if younger people reported different changes after their first use of EnChroma glasses versus older people. For ease, I broke up the ages into three groups based roughly on data suggesting cognitive decline of some mental abilities begins in the 20’s or 30’s but mainly because my sample size is so low. “Young” spans 0 – 29 years old, 29 – 39 “middle”, and 40+ being simply “old”. This results in 15 young respondents, 16 middle, and 11 old. Obviously it would be nice to have more bins, but it is what it is. The two hypotheses I postulate are 1) younger people will report more change overtime, eg more reports of “drastically”, than older people, since their brains have the capacity for more change. Or, on the contrary, since younger people’s brains are so plastic and quick to rewire, 2) younger people will not report much change after their first experience with the glasses because the changes take place so rapidly.

With this very tiny data set that brings little reliable evidence, it appears the data leans ever so slightly to the second hypothesis. More young people (33%, 5 people) reported only “a little” change compared to 13% (2 people) of middle and 18% (2 people) of old. This trend continues with 53% of young reporting “somewhat” of a change compared to middle (25%) and old (27%). Only 2 young people (13%) reported drastic changes compared to 44% of middle and 18% of old. Old people had a pretty flat distribution to the four choices. Old people were the most likely (27%) to report only some colors continued to change, most often greens.

 

 

It could very well be young people’s greens rapidly rewire circuits with their very first experience while middle people’s greens take more time to change and settle, resulting in drastic changes over time. Old people may have the most varied responses to change due to long term health trends, such as physical fitness (a large factor brain plasticity), being primarily responsible for their plasticity levels. I do not want to read too much into these results at this time though, the sample size is just too low and the question was admittedly a bit vague.

How long do you think it took your brain to adjust and stabilize to the glasses?

Carrying with neuroplasticity, I also asked, “How long do you think it took your brain to adjust and stabilize to the glasses?”. This question may also help us to figure out the age related neuroplasticity with more clarity. Two main groups emerge with 31% reporting “Within minutes” while another 31% reported “Within the first week”. Next most prevalent was “Within hours” at 17%.

 

 

Again, using the same age ranges as above, I looked to see if the time course had anything to do with age. The sample size continues to make things very difficult, especially any sort of statistical testing. Therefore, I combined “within minutes” with “within hours” as well as “within days” with “within one week”. “Within a month” and “still not sure” were left independent. There were 8 people who had EnChroma glasses for the less than a week and 5 people had them for 1 – 2 weeks. Three of these 13 people reported they are “still not sure”, so keep that in mind while interpreting these findings.

Continuing to support the hypothesis that younger people’s brains are more plastic and therefore change and stabilize at a quicker rate than older people, 67% of young people reported their colors stabilized within minutes to hours, compared to 38% middle and 36% old. Furthermore, young people were least likely to report within days to weeks, with 20%, compared to 31% middle and 55% old. Lastly, no young person reported within the first month, while 13% middle and 9% did. As for those still unsure, 1 young and 2 middle people had EnChromas for less than a week. It may be that younger people do indeed have more plastic brains and their color processing stabilizes quicker relative to older people. While interesting, more samples are required to determine if this is of any significance or simply due to low sample rates and natural variance.

 

 

A final plasticity inquiry consisted of two questions, “How effective were the EnChroma glasses initially at improving your color vision?” and “How effective are the EnChroma glasses now at improving your color vision?”. A response of a 1 indicated “not effective” while a 10 was “entirely effective”. I realize these questions are very vague, especially the “now” and may be useless, so it goes. A clear but small improvement trend over time is seen with the average initial improvement being a 6.8 (median, 7) and the average current improvement being a 7.5 (median, 8). At the least this adds a bit more credence to the notion there is some longer term neuroplasticity taking place and at best shows EnChroma  glasses improve many people’s color vision at least moderately with some getting used to.

 

 

Seeing new colors

The most reported colors that people with EnChroma glasses had never seen before were again purple (38% of people) and pink (31%). Orange even overtook green with 21% verses 17%, quite different from the general population of people with color blindness. However, this graph may be more accurate since EnChroma users will better know which colors they weren’t seeing previously.

 

 

What colors do EnChroma lenses affect the most?

I was curious to see if EnChroma was better at clearing up some colors over others. Rather than just what was the single best color improvement, I asked which colors could they discriminate better with EnChroma glasses on. Green just barely pulled ahead here at 62%, purple was not far behind at 55%. Green, purple, and red were reported to be the most problematic to people with color blindness at large (above). EnChroma seems to help a lot on the green and purple front but pinks improve more than reds which don’t improve much more than oranges. This again may be due to the large variety of greens in the world, plants, so there is more input to refine. Or that EnChroma glasses just work better with shorter wavelengths and are not tuned for longer, redder light.

 

 

Color vision is of course more complex than just broad color categories, so here are some written responses to the above question:

• “just its easier to tell colors and they are much brighter and full”
• “Shades of colors that had previously blended in.”
• “I didn’t know there were so many variations of blue! And same with every single color!!!”
• “TONS! I feel now that I need a translator with me to tell me what I am seeing as I have no real point of reference.”
• “I thought I knew what green was, but I didn’t know what I was missing. Enchroma revealed green as a deep and vivid color.”
• “Many. I see them in flashes when I close my eyes, like my mind is memorizing them. I can spot a new color automatically. My brain screams that it’s something new.”
• “…being able to distinguish shades of reds, greens and pinks really blew my mind.”
• “I kind of knew all the colors, but didn’t realize that some things were the color they are. For example, I didn’t realize neon colors existed in nature as much.”
• “I knew they existed, but just wasn’t sure what they actually looked like (their existence was conceptual to me)”
• “…Orange in the sunset sky – this is a whole new experience for me”
• “Most shades of all the colors.”
• “Greens are much more plentiful now”
• “I knew the colors existed, if only by words. However, while at the zoo, I saw flamingos. I always thought they looked dirty because they were grey.”

Seeing new colors, without the glasses

The most exciting result of all, and something that EnChroma Inc is very interested in, is if people have improved color vision after using EnChromas without wearing them. The idea is, that while wearing EnChroma glasses, colors becomes easier to discriminate and colors people had never seen before now come into their conscious perception. But, could it be possible that these new colors can be continually used by the brain as it reconstructs the color world without the aid of EnChroma glasses? Once the concept of purple was experienced and learned, could that be applied to things without EnChromas? Do our visual cortices reach into our memories when re-creating the scene in front of us? The results show a small, but very real, yes. 43% of people with EnChroma glasses reported no, they cannot see new colors without the EnChroma glasses on. However, 19% report they can now see purple without wearing EnChromas, 10% for pink, and 7% for red, orange, and green:

 

	Number of respondent	% of respondents
White	0	0%
Pink	4	10%
Red	3	7%
Orange	3	7%
Yellow	2	5%
Green	3	7%
Blue	0	0%
Purple	8	19%
Black	0	0%
Grey	0	0%
Brown	1	2%
No	18	43%

 

These data indicate there may be a subset of people that once they have experienced purple with EnChroma glasses, it is easier for them to reconstruct the experience with the muddled inputs that come in when they do not have EnChroma glasses on. Once their purple neurons have been activated, they can easily be reactived even by a noisy signal. Quite astounding indeed.

 

How many people want EnChroma glasses who do not have them? Why don’t they have them?

Many of the color blind respondent who do not have EnChroma glasses, 74%, do indeed want EnChroma glasses. Only 4% do not. The remaining 21% were still on the fence. So, why don’t they order them? Well they’re expensive. The least expensive pair of glasses start at $269 non-prescription and some models can go as high as $699 for a progressive prescription pair. With the growing popularity of online, low price prescription glasses, people aren’t forking over the hundreds of dollars they used to at an optometrist boutique for glasses. 73% of people cited cost as one of the reasons they are not buying the EnChroma glasses. 42% cited they were unsure they would work for them, 12% were content without them, and 5% waiting on more reviews.

Comparisons across “normal” vision people and those people who are color blind

Favorite colors

As you may expect, if people who are color blind cannot see a particular color or colors, it will be impossible for them to have that color as their favorite one. Also, some colors may be discernible but vague or blunted to their perception. So are there differences in favorite color across those with color blindness and those without it? Indeed these seems to be some interesting trends with, yes you guessed it, purple striking again! The single largest different in favorite color by percentage of respondents was purple with a difference of -15%. All calculations are color blind – non color blind. 18% of those without a form of color blindness reported that purple was their favorite color compared to just 2% with color blindness. Following purple was of course green, at -8%. Going the other way, people with color blindness find yellow (8% margin) and blue (7%) to be more appealing than those without color blindness. I find the yellow and orange difference to be interesting because both colors heavily rely on red and green cones, one of which is often not functioning properly. Perhaps whatever oranges and yellows come from those tweaked cones are more beautiful than the oranges and yellows people without color blindness see. Interestingly, blue was the most favorited for both groups by a long shot. This is consistent with other studies; people just love blue water and skies.

Hover over to compare favorite colors of without color blindness to those with color blindness.

 

Practices in art

I was interested in if people who were color blind sought out different artist outlets for their passions. There is of course no reason for someone who is color blind, even someone who is totally achromatic as in the case Oliver Sacks outlines, to not paint or draw but such mediums could be difficult. The wonderful painter in Oliver Sacks’ case did, after much effort, give up painting with colors once he lost all of his color perception. He did, however, continue to produce beautiful and moving paintings in black and white.

There was little difference in both groups for people who do not take part in any form of art, 31% color blind and 29% non-color blind. However, a higher percentage of people without color blindness can be found in nearly every form of art compared to those with color blindness. Even in art forms that do not require full color vision per se, such as crafts, creative writing, or poetry, those who are not color blind report a much higher occurrence of practicing them compared to those who are color blind. There was not a single art form in which the non-color blind had a higher percent occurrence than those without color blindness except for sculpting, which was equal. Perhaps people who are color blind feel as though they can’t practice art? Or are not encouraged to at a young age? Or maybe this is a sampling error, the margins make me doubt this though.

 

How important do you think full color vision is for a complete experience of the world?

I wanted to know if those who had color blindness felt as though there were missing out on their experience of the world. I was also curious to see if people with full color vision took for granted their colored world or if they felt as though it was necessary to complete their reality. A response of 1 corresponded to “not at all” and a 10 with “completely necessary”. Intriguingly, the results were nearly identical. The average response for those with color blindness was 6.7 (median: 7) while those without was 7.1 (median: 8), Mann-Whitney U Test, p = 0.27. It was, however, more likely for someone with color blindness to report a number closer to 1 than it was for a a non-color blind person. This may be due to those with color blindness being perfectly content in their one-of-a-kind colored world.

 

Color vision and careers

Recapping from earlier, the average color blind person’s response to “Do you feel as though your color blindness limits your employment opportunities?” was a 4.6 (median: 4), where a 1 meant “not at all” and a 10 meant “severely affect”. Rather an indifferent response overall. Furthermore, 41% of people would not have pursued a different career. 26% say they would have, and 32% were “not sure”. Does full color vision matter all that much though in the working world? Indeed it seems to, with 22% of “normal” color vision respondents reporting their job does require full color visions; a percent much larger than I had anticipated. Hopefully EnChroma glasses and other color vision therapy techniques in the future will allow more people to pursue jobs they have a passion for.

EnChroma video reactions

I think part of why EnChroma videos have gained such viral popularity is the deep emotional response they invoke in those who are watching someone see the world in full color for the first time. I was wondering if people who did not have a full color spectrum in their world felt more emotional when watching the videos and longed for the experience, compared to “normal” color vision people who could empathize with what it is like to see all the colors in a sunset. Similar to the “complete experience of the world” question,the averages were nearly identical across the two groups, color blind 6.6 and non-color blind 6.3. 1 meant “meh”, 10 meant “deeply emotional”. However, it seems as though those with color blindness tended to report on the extreme ends of the spectrum with many more 1’s and 10’s whereas those without color blindness reported more medial ratings. Indeed, a Mann Whitney U results in a p value of 0.06, a strong trend that indicates people with color blindness may be having a different emotional response than to those who are not color blind.

I also asked both groups what emotions it was they were feeling when they watched the videos. I scanned through their responses for some general emotions; happy/happiness, joy, sad/sadness, empathy, envy. Emotions are of course difficult to measure and many people had a lot to say about their experiences. This is no way is comprehensive of all the different things different people start, but I think it gives a rough over view. 126 people with color blindness wrote in their emotions while 123 people without color blindness wrote in there’s. Excuse my ugly graph.

Positive affect emotions well outweighed negative affect ones. Joy and happiness were the most frequently reported feelings however they were disproportionately more people without color blindness feeling good than people with color blindness. Emotions like sadness, envy, and jealously were more likely in those with color blindness. It does seem like many people with color blindness are excited about the prospect of getting EnChromas themselves and the opportunities out there. I imagine if the price goes down many more people will be interested in them. Below are some examples of responses:

Responses by people with color blindness:

• “excited to be able to see the colors that I have never seen before”
• “Annoyance. I do not believe they work, or are mainly staged. I’m also sick of /r/colorblind being used to shill them off on people.”
• “Jealously. Curiosity. Happy that I live in a time where I may be able to experience all colour.”
• “Happiness that someone can see the world the way humans believe it ought to be perceived.”
• “is “annoyed that colour normal people are using us as their feel-good inspiration porn” an emotion?”
• “Fear. If I try them, would I want to take them out? Would affect me seeing what I’m missing?”
• “I think the subjects in the videos are overselling it. Although I am colour blind and my wife and kids find it fun to point this out on occasion, I don’t feel in any way diminished. There are many forms of colour blindness of varying degrees of intensity. I find it funny when people who don’t understand colour blindness assume I see in black and white. However, I can’t imagine seeing colour how non-colour blind people see colour to be as awe inspiring as depicted in these videos. This may be however because I have not tried these glasses.”
• “Having been one of those people, I truly felt a profound sense of understanding and longing when I first saw the EnChroma videos. I remember feeling excited, then moved, and then jealous because I didn’t have that experience. Before I knew it, I had gotten my own pair and felt exactly the way they did. There is a desire to know and understand how the rest of the world views color. Seeing that video made me feel a sense of ease and happiness in knowing that technology could make that experience possible for me.”
• “Curiosity and interest. I was actually not believing it until I did some research myself.”

Responses by people without color blindness:

• “I have never even heard of EnChroma”
• “I’m a mother. To me seeing color or seeing at all for the first time is like being born into a new world and the people around them are sharing that new world. People who have never had these advantages (or people that lost them) appreciate it so much more. The way they articulate it (even the cursing) is a wonder. Even in a video you can feel that wonder and innocence that only someone experiencing light, color or sound for the first time can convey.”
• “Profound sadness imagining not being able to see certain colors, sympathy for the person, joy for the the person’s new ability!”
• “Pity because of how long they missed out on certain colors, happy that they finally got to see what most others see.”
• “Happiness & compassion. It is lovely to watch someone experience the beauty of colour for the first time.”
• “Somewhat annoyed – they’re the kind of thing that sites like the Huffington Post put up daily. Sure it’s great that people can see more colors than they did before, but why should other people’s lives/health issues be that interesting to me?”
• “I start getting very warm on the inside and every time I watch the faces of people who can see colors for the first time it makes me cry. Even now I’m starting to tear up because I’m thinking about how they reacted, I’ve been thinking about these glasses all day. I wish I could see what it’s like to be colorblind because I want to experience life to the fullest and that would be a part of it.”
• “Must be cool for the people “seeing color” for the first time, but I don’t really think they’re seeing it the way non-colorblind people do. Then again, maybe each non-colorblind person sees color differently than the next non-colorblind person, so who knows.”
• “Sadness for experiences missed. Joy for the gift these individuals have been given.”

Conclusions on EnChroma glasses

Overall I think it is fair to say EnChroma glasses work very well and have a positive impact on the lives of those with color blindness. Greens seem to be most improved followed by purples. pinks, and red. Forests and sunsets should be a whole new experience for those who can foot the bill. Hopefully EnChroma can lower their price point in the future because the demand seems very high.

Discussion

The overarching idea behind all of this was inspired by the likes of Radiolab’s Color episode and the wonderful writings of Oliver Sacks. These, and many other works, demonstrate the color is not as straightforward as different wavelengths of light hitting our eyes. Rather, our environment and culture, such as the language we speak, has an influence on what colors our brains bring into our conscious perception. In the experiment EnChroma has set up fortuitously, people who had never previously experienced the full spectrum of color now have the hardware to do so. These people also have all the language in place to categorize colors; many know of purple but few knew what it was like to perceive purple. And here it was found, despite many respondents never before perceiving purple, they now can with EnChroma glasses. Extraordinarily, purple pops into their perception nearly instantly. Never before had a purple neuron been activated yet instantly it began firing when the EnChroma filtered light fell onto the retina and these signals were processed in the brain.

However, the category of purple had existed in their brains for a long time; largely empty of purple content and rather full of muddled greys they know must not be correct. Intuitively, at least in the case of Ethan, people seem to know what it is to see purple near instantly. Though uncertainty remains with many people as they ask for reassurance on their assessment of the newly colored world, they seem to be quite accurate in discriminating colors in their new reality. The question of “what it is to experience purple” has fascinated philosophers for centuries. The remaining lack of understanding that is left after learning everything you can about a concept, like purple, without having directly experienced it is referred to as qualia. While indeed many people trying on EnChroma glasses learned the qualia of what it is like to see purple, apparent by many being brought to tears by the new knowledge, there seems to be at the least knowledge about, if not an intuition about, purpleness that exists prior to the experience of purple. This of course is likely from learning about it through language. In the classic qualia thought experiment the agent is always full color blind (achromatic) so they have no reference to color at all. However, it seems as though when people have experienced other colors and have language to categorize them, the qualia gained from a new color may be less than that of an achromat seeing purple for the first time and knowing about purple only from textbooks.

A further question begs answering, how were people with color blindness able to instantly perceive new colors? Language again may be the culprit. The idea of purple was well known to these people however it was void of any accurate experiential knowledge. I can’t imagine how frustrating it must be to not be able to discriminate a purple number from a differentially colored background. A desire in perceptual knowledge fueled by years of frustration may have driven the color processing regions to grasp at any new stimuli to fill the void. Coupled with learning about what purple should be like through language, say, “sort of blue but with some red in there”, the rapid conscious perception of purple is not too surprising on this psychological level.

But how did it happen so quickly neurophysiologically? How were these purple cells and synapses so readily accessible? Prior to EnChroma glasses, their experience of purple was painted by the activation of short cones concurrently with an overlapping input from medium and long cones. Now, however, the shorter-long wavelengths erroneously activating the medium cones have been filtered out and the long cone signal could dominate the medium cone’s. Was it then the case that the visual cortical neurons responsive to the old noisy signal were tuned broadly enough to process the new input? Put differently, was it the same cells responsible for the muddled color that also created purple? Or did other cells abandon their favorite signals to be selective to the new exciting purple flowing in? Or did there exist a pool of “purple” neurons in the visual cortex that so desperately longed for an input of only short and long wavelengths and were ready to splash consciousness with purple whenever that input finally came? I find the latter explanation hard to reconcile as I would imagine these neurons would be re-purposed after a lifetime of no input. However, it could be the case these neurons continually received just enough input to stay alive but never enough to bring about purple. Secondly, could the downstream associative neurons under the influence of language’s purple schema readily accept and make sense of this new purple information? And again whatever the case may be, how did this happen so quickly?

I would like to take a step back and point out I am likely highly oversimplifying the topic. Seminal color study in monkeys using electrode recordings have shown only a subset of cells in Visual Cortex Are 4 (V4) are true “color selective cells” and rather respond broadly to long or short wavelengths (Schein et al, 1982). Many neurons in V4 are selective or biased to a particular wavelength, but many others are not (Zeki, 1983). Indeed, later studies have shown V4 is a complex region processing lots of information outside of color, such as spatial information like length, width, and orientation of lines (Desimone et al, 1985; Tanigawa et al, 2010).There are definitely neurons in the monkey V4 tuned to purple but these cells can change their purple tuning depending on the colors surrounding the purple (Kunsunoki et al, 2006). Furthermore, Desimone demonstrated neurons outside of the visual cortex are also color sensitive, such as in the inferior temporal lobe; a region of particular importance to memory. Moreover, as we currently understand it, our nervous system process colors in two very different ways. One referred to as opponent process theory (for review, Shapley & Hawkin, 2011) which is complicated but powerful and prevalent in many brain regions for signal processing. The other, Young-Helmholtz Trichromatic theory, is more akin to the additive color mixing we know intuitively. Complicating the matter even further, a massive amount of color processing is done in the retina of your eye before the signals are even sent to your brain. Even further processing is done in the thalamus. While we know V4 is very important for color perception and that some neurons there selectively respond to different colors, how exactly that process takes place to make a purple cell and then where purple is sent from there is beyond my level of knowledge. I feel like I don’t have enough visual processes expertise so I will stop here on speculating what mechanism may be employed by the visual system to handle new EnChroma filtered wavelengths. Though, if I were to guess, I would say the V4 neurons broadly tuned to short wavelengths and a mixed medium/long input would also process the new, clearer short-long dominate signal and through rate coding send downstream structures the proper information. Overtime, some of these neurons would become more selective to only short-long wave length input and become purple neurons. But how does all of this happen so fast? This is something I do know a bit about.

On the neuroplasticity front, the data seem to indicate younger people with EnChroma glasses are quicker to adjust to new colors and over time these colors change less compared to older people who take longer to adjust and the adjustments are more drastic. If this effect is indeed true and not due to my limited sample size, the intrinsic plasticity of younger brains may be partially responsible for how rapidly they adjust. What is still remarkable is just how quickly all age groups can see new colors. There is no need for massive circuit level changes involving the scaling of synapses and production of new proteins from the nucleus of neurons that takes hours. Local protein synthesis at a synapse, which can happen near instantly to seconds, may be sufficient for rapid synaptic changes and lead to the effective processing of the new purple signals. It may also be neuroplasticity and circuit changes are not needed. Perhaps the gene controlled wiring of our color vision circuits are static and resistant to input specific plasticity. These circuit may persist as they were originally wired up to process the full spectrum of visual light and therefore all the necessary circuits to process purple are still present. Or, as alluded to above, it may be a physiological property of V4 (or other regions) neurons to be able to encode a wide range of wavelength inputs.

How does purple get into conscious perception? Why is it not ignored? Or just grouped in with blue?  How is it separated out and attended to? It may be the downstream, preexisting, but void, circuit set up by the language category for purple makes apparent purple to consciousness. It likely also works to sort purple, comparing the purple pattern of activity to the blue and to the red and other colors, separating out what is different but associating what is similar. Red is a warm color while purple is not, these are separate. Blue is a cool color and so is purple, these are similar. This is how our brain distinguishes memories of events so they do not overlap. With the preexisting knowledge of purple setup and in waiting, the new purple information integrates in quickly and easily.

Conclusion

What we may conclude with some certainty is that people who have a language full of color words, are color blind, and then use corrective means to aid their color blindness, new conscious color perceptions are near instantaneous, possibly due to the broad processing capacity of the visual system, and there seems to be an intuition present, possibly due to knowledge from language, allowing these people to correctly assign their new colors with language. Overtime, their processing of new colors and their ability to discriminate across colors will be improved and the time course of this may be age dependent.

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As I stated at the top, for those who know more than me on the topic please do get in touch. I would love your insights on the questions at hand.

You are free to use this data as long as you give proper attribution to me as outlined in the CC license of this work (below). The Google Sheet can be found here.

If you would like the organized responses to the survey in Excel with all my formulas, please email me: blakeporterneuro@gmail.com

I’d like to acknowledge Maddie Kyrke-Smith for her helpful comments on neuroplasticity.

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References:

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This work by Blake Porter is licensed under a Creative Commons Attribution-Non Commercial-ShareAlike 4.0 International License

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