There are inconveniences, but civil servant says living with red-green colour deficiency isn’t a major problem

Civil servant Joshua Chow, 30, was only in primary school when he found out he was colour blind. He has trouble telling green from red when they are placed together.

It ruled him out of certain occupations, according to a one-page list the young boy was given when he went for further tests.

“Scientist was one of them, but I didn’t really take it to heart,” said Mr Chow. “And it was very early on... so I didn’t really know what I wanted to be.”

Fishmonger and pilot were also out, the boy was told.

Nevertheless, science was his favourite subject throughout his school years. In 2014, he earned a master’s degree in science from ETH Zurich, a Swiss university.

Mr Chow has deuteranomaly, a type of red-green colour deficiency. Red-green colour deficiency is generally hereditary and is the most common type of colour blindness worldwide.

This is among three main types of colour blindness – the others being blue-yellow colour blindness and complete colour blindness – and its effects can range from mild to severe.

Between 7 per cent and 10 per cent of males worldwide inherit colour blindness, compared with less than 1 per cent of females, according to Dr Chin Chee Fang, a consultant at Tan Tock Seng Hospital’s NHG Eye Institute.

“People with inherited red-green colour deficiency live normal lives and can pursue most careers,” Dr Chin said, adding that they learn to adapt from a young age.

While colour identification is critical for people who are electricians or chemists, it is not for those in accountancy, business, law and medicine, said Associate Professor Audrey Chia, head of paediatric ophthalmology and strabismus at the Singapore National Eye Centre.

Living with deuteranomaly – in which yellow and green appear redder, and violet and blue are hard to tell apart – has not been a major impediment, said Mr Chow.

It can, however, lead to some daily inconveniences or faux pas, such as when hailing a taxi.

“I can’t tell whether (the taxi sign) is green or red, so I just raise my hand,” said Mr Chow.

“Someone asked me, ‘Why are you raising your hand when all the cabs are red? Can’t you see?’ and I was like, ‘Possibly not,’” he recalled with a laugh.

When it comes to shopping for clothes, he once bought a “grey” jacket that turned out to be green.

He learnt ways to skirt the problem, such as by reading clothing labels or getting a friend to shop with him.

While he was doing his master’s degree, he switched the colours assigned by the computer – which is linked to a microscope – to a live image of plant cells from the usual red and green, to yellow and purple.

Two years ago, a friend bought him a pair of tinted spectacles costing $500 that helps users better differentiate colours.

The spectacles work by increasing the illumination over the object or increasing the saturation of the colour, according to Dr Marcus Tan, an ophthalmology specialist and consultant at Raffles Eye Centre. They block out certain wavelengths of light. For instance, red is a long wavelength and green, medium.

However, Dr Tan cautioned that blocking out the wavelengths of light can create a relative blind spot and lead to objects being blocked from or disappearing from the wearer’s vision.

“I realised most things look pretty much the same, aside from a few things, like purple is a lot more purple,” said Mr Chow, who uses the special glasses when on holiday.

“I wore them once to a light show and people... were wondering why this guy was wearing sunglasses at night, especially at a light show.”

People are often curious when they find out about Mr Chow’s condition and try to test him with colours.

“Aside from that list (in primary school), nobody actually told me what I couldn’t do,” said Mr Chow, who has two male cousins with redgreen colour deficiency.

His parents and younger sister do not have any colour blindness.

Recalling the colour test in primary school, he said: “I think my mum was quite sad. I discovered this only in later years. She would always bring up that list (of jobs).”

Mr Chow said his colour blindness does not pose a big problem and has very little effect on his life. Instead, he and his family have learnt to see the funny side.

“They just find it funny, and I find it funny too when I make mistakes.”

Seeing colours differently

About 4% to 8% of the population has colour blindness, the most common of which is red-green colour blindness. Most cases of colour blindness are inherited, and these do not progress with time. There is, however, no cure for inherited colour blindness. In other cases, colour blindness may develop as a secondary effect of macular and optic nerve diseases or as a result of taking certain medications. 

Colour blindness brought this couple together

Mr Chong Kwek Bin and Ms Tan Li Ping are in many ways an ordinary married couple, except they share something unusual in common – they see colours in similar ways.

Dark colours appear black and light colours, white. They cannot tell red, orange and yellow apart, or distinguish certain blues, greens and greys.

They met when Mr Chong, 36, was conducting IT classes for the visually impaired five years ago.

Ms Tan was a former clinic assistant looking for a new job. She had signed up for the classes over six months to upgrade her skills.

Mr Chong, an IT programme executive at the Singapore Association of the Visually Handicapped, said he was attracted to her “cute personality”. The weekly classes drew them closer and they continued to meet after the course ended.

“He’s very caring... not just towards me, but also others,” said Ms Tan, 44. The couple tied the knot after 11/2 years of dating in 2015.

Mr Chong’s limited colour vision and general loss of vision stem from a group of rare genetic disorders called retinitis pigmentosa. People with the condition have night blindness and lose their peripheral vision, resulting from a breakdown and loss of cells in the retina.

Ms Tan also has vision loss, caused by diabetic retinopathy – an eye condition in which blood vessels in the retina are damaged. It developed when she was 16 due to poor management of Type 1 diabetes, which she has had since the age of eight.

“Colour vision actually never really figured in our relationship until we had to live together,” said Mr Chong. “We put our toothbrushes in the same cup; mine is green and hers is red, but she says she can’t tell the colours apart.”

When it comes to buying clothes, Ms Tan identifies the colours with the help of sales staff, and writes down the colour on the hanger.

At work – she has gone back to being a clinic assistant – she seeks help from her colleague to identify patient files, which are colour-coded.

Ms Tan’s sister and brother also have diabetic retinopathy.

While her eye condition has stabilised, Mr Chong’s vision has been deteriorating slowly. He sometimes sees flashes of light.

His older brother, an IT professional, has a gene for retinitis pigmentosa but has perfect vision.

These days, Ms Tan helps her husband to move around, calling herself his “human cane”.

For overseas holidays, the couple, who do not have children, travel with family or friends.

“I’ll tell people, ‘We can find our way overseas, but we can’t find our way back,’” Mr Chong joked.

“Even if you’re colour blind, you can still see shades of colour. You’ll still be able to see meaningfully.

“Colour deficiency is at most something to be missed, but not something that should seriously impact people,” he added.