Architect Yoshimasa Yano is unable to recall the moment he first became aware that his perception of color differed from that of his family or friends.

In the fourth grade of elementary school, however, Yano failed a color vision test. His parents weren’t surprised by the result.

“My parents took a variety of measures to ensure I didn’t embarrass myself in public,” says Yano, who insisted on using a pseudonym when speaking about his condition.

“My color vision deficiency must have affected a few things in my day-to-day life but, to be honest, I don’t recall experiencing any major difficulties,” Yano says. “I was pretty much able to deal with everything without a problem.”

Yano’s parents always supported his interest in art. Instead of trying to steer Yano away from a subject they believed would be difficult, they taught him strategies to manage his difficulties.

For example, Yano preserved labels on crayons for as long as he could and, once they were gone, made sure to put them back in the same place in the palette to ensure he wouldn’t get them mixed up.

Mixing paint, however, was a different story altogether.

“I understood the theory of how to mix paint together in order to create new colors but I could never do it properly,” Yano says. “However, I had a great teacher who challenged us to paint what we saw in front of us, not what we imagined it would look like.”

Color vision deficiency affects more than 3 million people — about 1 in 20 men and 1 in 500 women — in Japan. The condition is most commonly inherited from mutations in the X chromosome, although it can also be acquired through eye disease such as glaucoma or as part of retinal damage caused by diabetes.

The human retina contains two kinds of light cells that help detect color: rod cells, which are active in low light, and cone cells, which operate in well-lit settings. Three kinds of cone cells typically exist, each containing a different pigment that is activated when it absorbs light.

The light sensitivities of the cones differ; one cone is sensitive to short wavelengths, one to medium wavelengths and the third to medium-to-long wavelengths, with peak sensitivities of each cone helping to detect blue, green and yellow-green, respectively. Red is detected by light stimulating the long wavelength cones.

A deficiency in color vision typically occurs when the rods or cones do not function properly.

Experts have identified three broad types of congenital color vision deficiencies: monochromacy, dichromacy and anomalous trichromacy.

Anomalous trichromacy is the most common type of inherited color vision deficiency, occurring when one of the three cone pigments is altered in its sensitivity to light.

Dichromacy is a more severe condition and occurs when one of the cone pigments is missing and color vision is limited to two dimensions.

Monochromacy occurs when two or all three of the cone pigments are missing, and color vision is limited to just one dimension. In such rare cases, a person lacks an ability to distinguish color altogether.

People with congenital color vision deficiencies typically have difficulty distinguishing between red and green, orange and yellow-green, green and brown, blue and purple, and so on.

History of discrimination

In 1794, English chemist John Dalton presented a paper on color vision deficiency titled “Extraordinary Facts Relating to the Vision of Colors,” which described his own problems in identifying color. The condition became more widely known after a fatal train crash in Sweden in 1875 that is believed to have been partly caused by the driver’s color vision deficiency.

In 1916, meanwhile, ophthalmologist Shinobu Ishihara developed a diagnostic test that remains the most common way of screening people for color vision deficiency worldwide.

In the test, subjects are asked to examine a series of pictures of colored spots and identify a figure (usually one or more digits) that is embedded in the picture as a number of spots in a slightly different color. Such figures can be seen by people with normal color vision, but not by those with particular color defects.

Ishihara’s test was initially used to screen soldiers in Japan and those who failed it were barred from enlisting. People who failed the test increasingly found themselves facing discrimination in terms of marriage, employment and even education.

Kaoru Nakamura, an ophthalmologist at Tokyo Women’s Medical University, says there is a long history of discrimination against people with color vision deficiency in Japan.

“Discrimination against people with color vision deficiency was strong back then (in the 20th century),” Nakamura says. “Marriages were annulled, job applications were rejected and people were turned away from almost every college science course in the country.”

The situation has improved, Nakamura says. It’s worth noting, for example, that the Japan Ophthalmological Society has banned the use of the term “color blind” in official documents, as it reinforces a perception that people diagnosed with color vision deficiency cannot see color at all.

Although an effective treatment for the condition has yet to be discovered, some parents — mothers in particular — express guilt over passing the defective X chromosome along to their children.

“Most people (with color vision deficiency) don’t experience any problems in their day-to-day lives. In fact, there is very little that they are unable to do,” Nakamura says. “Many mothers, however, blame themselves for their children’s congenital condition, even though it’s not their fault. Mothers in this situation actually need quite a lot of emotional support.”

A few decades ago, an eye clinic in Tokyo claimed to be able to cure a person that suffered from color vision deficiency.

Desperate mothers that had children with congenital color vision deficiency paid hundreds of thousands of yen for electronic sessions at the clinic in the hope that the condition could be reversed, according to the Color Universal Design Organization (CUDO).

In 1980, however, the Asahi Shimbun described the treatments as “phony,” saying they had no scientific basis. The clinic sued both the newspaper and the reporter behind the story for damages and demanded an apology, but the Tokyo High Court ruled in favor of the media organization in 1990. The sentence was finalized in 1994.

CUDO deputy chairman Yosuke Tanaka, who was diagnosed with color vision deficiency as a child, went through 10 to 20 sessions himself at the clinic in the early 1990s.

Tanaka recalls being able to distinguish color a different way following a session in which he received electric pulses near his eyes. The next day, however, he awoke to find that his eyesight had returned to its previous state and he stopped the treatment a short time later. Tanaka does recall hearing about people at the time who did claim to be cured.

“I was amazed to walk outside and see the world in technicolor,” Tanaka says. “I was even able to identify more numbers in the Ishihara test that day as well. The next day, however, everything was back to the way it was. I challenged myself to do the test in the hope I could be cured but I’m not overly despondent about the end result.”

Creative solutions

For a long time, people with color vision deficiency had limited job prospects. Indeed, they were actively discouraged from becoming doctors, pharmacists, chemists and artists.

However, only a few occupations place restrictions on people with color vision deficiency these days, including pilots, train drivers, police officers and Self-Defense Force personnel.

These rules differ somewhat depending on location. Tanaka, for example, has a pilot’s license in the U.S. and is allowed to fly airplanes there during daylight hours. He would not be able to receive the same license in Japan.

Elementary schools, meanwhile, were once obligated to test students for color vision under the 1948 School Health Act. Nakamura, however, says that failing the test in front of classmates used to be a traumatizing experience.

The government banned blanket testing in schools in 2003 after opposition from parents grew. However, the Japan Ophthalmological Society has been calling for the test to be reinstated, arguing that it was better for people to know they had color deficiencies early in life.

From April 1, elementary schools reintroduced the test, but an ordinance issued by the Ministry of Education, Culture and Sports two years ago requires schools to acquire parental consent before conducting the test. The school is also required to conduct the test in a private setting.

“A number of people don’t know they have color vision deficiency because the condition is very subjective — they can’t compare what they see with what other people see,” Nakamura says. “Without knowing they have difficulty distinguishing color, however, they will face unexpected challenges.”

In Sendai, a junior high school teacher is currently on trial for causing a fatal traffic accident on the morning of June 2014, killing a taxi driver and a female passenger. The teacher ran through a flashing red signal thinking it was yellow — he has color vision deficiency.

Signal lights nationwide are currently being switched over to LED, which lasts longer and uses less energy.

As of March 2013, there are 2.23 million signal lights nationwide, of which 840,000 are LED lights, according to the National Police Agency. Eye experts and people with color vision deficiency, however, note that red and yellow LED lights are more difficult to distinguish.

According to the teacher’s lawyer, Hiroshi Sogo, the defendant, who is in his 50s, was diagnosed with color vision deficiency during blanket screening at elementary school, but that was as much as he knew about his condition.

He had never experienced any issues related to color before the accident, Sogo says. The driver had also gone through the same flashing red signal on two prior occasions, thinking that it was flashing yellow.

“It is the only world that he knows,” Sogo says. “He never realized his vision was any different from anybody else’s. He didn’t have any problems with his color vision at all and he never thought that he would make such a dangerous mistake.”

The defendant doesn’t intend to use his condition as an excuse, Sogo says. He has been visiting the site of the accident every month on the day of the anniversary to lay flowers for the victims and has only stopped because the bereaved family asked him to.

“He knows he is to blame in spite of his color vision deficiency and we’re not trying to use it as an excuse,” Sogo says. “However, it is important for people to know that he didn’t run a flashing red light on purpose.”

To help people with color vision deficiency see red LED signal lights better, Taro Ochiai, a professor of environmental design at Kyushu Sangyo University in Fukuoka, has spent more than a decade developing a signal light that can be seen by all.

Ochiai has focused on how people with color vision deficiency actually perceive color — that many are sensitive to contrasting colors, as well as the color blue. As a result, he included a diagonal cross in the middle of the red LED signal light that emits a reddish purple color.

“As people with normal vision see red and reddish purple in the same category, the diagonal cross is visible only to those with color vision deficiency,” Ochiai says. “I devised this theory some time ago, but it took me 10 years to find the perfect combination of brightness and color.”

Ochiai’s signal lights have been tested in two locations — in Fukuoka and in Tokyo’s Minato Ward in 2012 — and he has made improvements since in response to users’ comments. The professor is reaching out to police in a bid to install the signal lights nationwide, especially in light of the upcoming 2020 Tokyo Olympic and Paralympic Games.

At the same time, however, Ochiai is aware that, based on feedback he has received, installing such signal lights could create a perception that people with color vision deficiency shouldn’t be driving.

“I am trying to ensure that everyone has access to the same information in order to create a safer society,” Ochiai says. “My work is based on the idea that we need to create new social designs in which everyone can live together.”

Universal design

CUDO is also trying to make a difference. Established in 2004, the nonprofit has been working alongside companies, organizations and municipalities, providing advice on the combination and contrast of certain colors so that they are easier for everyone to see.

The four deputy chairmen, including Tanaka, Koichi Iga and Masataka Okabe, who is also a professor of anatomy at Jikei University School of Medicine, all have color vision deficiency.

Working as an expert in genetics in 2001, Okabe came across a simulator on a website that showed how people with normal vision saw the world compared to those with a color vision deficiency.

To Okabe, the two images looked exactly the same. His colleagues, however, kept discussing the differences.

“I then realized that what I was seeing was completely different from everyone else,” Okabe says. “However, everyone is different and I wanted to come up with ideas on how we can live together in a diverse world.”

The world around us is full of information based on color, from subway maps and toilet signs to power buttons on television sets. CUDO has designed a color universal design logo that is stamped on electronic goods, maps, textbooks, facilities and other products that have been approved by the organization.

The organization has worked with the Meteorological Agency in a bid to change the colors of the weather warnings it issues. It has also worked with the city of Naruto in Tokushima Prefecture to create a color-friendly hazard map that identifies dangerous areas.

Last but not least, CUDO worked with Adobe Systems Inc. in 2008 to develop customized Illustrator and Photoshop software that includes a color-proofing function.

Subway maps were also altered in 2004 to help distinguish train lines, with Tokyo Metro Co. including initials on them to help differentiate them from each other.

Iga says the revision was a welcome improvement. Before the alterations were introduced, he says, he used to confuse different train lines all the time.

“The key feature about universal design is that most people don’t notice the changes, but improvements have been made to make a service, product or facility easier for everyone to use,” Iga says.

However, not everyone agrees with the effort put into universal design.

Yano, for example, says the colors people see are so diverse, it is hard to come up with a single combination that is easy for all to see.

What’s more, he says, colors can be perceived differently depending on lighting conditions. As the conditions vary so much, Yano believes that some would rather be left alone altogether.

“Trying to create a world without barriers is important but I think it should be done quietly to prevent harmful rumors or misunderstanding,” Yano says. “It is a very delicate and difficult issue because regardless of people’s best intentions, someone always gets hurt.”

Yano has been a member of Pastel, a support group established in 1989 for people with color vision deficiency and their family members, for more than 20 years. The group operates a hotline and produces a quarterly newsletter to share information. The majority of phone calls that Pastel receives are from desperate mothers who blame themselves for their children’s eyesight.

People who are affected by the condition, on the other hand, react in a variety of ways, Yano says. Some are not even aware they have issues with color, while others face problems in their day-to-day lives.

Yano, who has relatively strong symptoms, believes that adjusting the colors on signs won’t make much of a difference because society already follows fairly rigid rules on color. Job seekers are advised to wear a white shirt for an interview, for example, but a person with color vision deficiency may unintentionally wear another color.

“For many of us, it is not color itself that make our lives difficult but what it represents,” Yano says. “We are expected to communicate with others in society by being able to read the slightest nuances in color. For many of us with color vision deficiency, that is the trap that we fall into most often.”

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