As a person with colour blindness, Cael Millner has had a few setbacks in life.
There is no cure for colour blindness. Photo: africa-studio.com (Olga Yastremska and Leonid Yastremskiy)
After spending two years studying a landscaping course at polytech, he realised it was not the right career path.
"About 80 percent of the course was plant identification, which means identifying plants by their colour shades and foliage … that's something that I just wasn't able to do," Millner said.
"I got really unmotivated and lost interest in the industry, so I ended up leaving. That was pretty disappointing."
Millner then set his sights on joining the army.
"I decided to apply, but I knew that my colour blindness was going to affect the application … so, I kept it quiet on my application," he said.
"It wasn't until my second medical with the Defence Force that they found out and I was told that I wasn't able to join, which was absolutely devastating."
The 27-year-old now works as a drill rig operator and has learned to deal with his condition.
"I've got apprentices that can help out if I can't work something out because of colour, I'll ask them," he said.
Cael Millner is not alone.
About one in 12 males and one in 200 females around the world are colour blind.
Professor of experimental ophthalmology at the University of Sydney Paul Martin said people who have colour blindness may have difficulty seeing some colours, or see them differently from others.
"Their world still appears vivid, it still appears to be in colour - it's just that their colour sensations are different to that of about 90 percent of us," he told ABC Radio Sydney.
People with colour blindness see colours in a different way to normal-sighted people, Professor Paul Martin says. Photo: Gilles Targat/Photo12
The condition is often inherited but can also be caused by ageing or certain diseases.
It varies in severity, with the most common type being red-green colour blindness - which can make it difficult to distinguish the red and green components of colours.
"Colour is so important that we take it for granted," Professor Martin said.
"We use colour to navigate around the world … we use colour in many ways without being aware of it."
There is no cure for colour blindness, but companies have created glasses and contact lenses they claim help alleviate symptoms of the condition.
American researchers have used gene therapy to try and treat colour blindness in monkeys, but Professor Martin said there was still a long way to go before there was a cure.
"It potentially could happen sometime in the future, but it's at a very early and experimental stage," he said.
Specially adapted contact lenses may help with colour blindness. Photo: 123RF
Life choices
David Gaggin's childhood dream of joining the Navy was crushed at the age of 15, after a medical test revealed he was colour blind.
"I applied for the Navy … I got through all the interviews," Gaggin said.
"But when I went into the final interview with a doctor, he said 'did you realise that you're colour blind?'
"I was pretty devastated at that point."
The diagnosis was a shock to Gaggin and severely affected his self-confidence.
It also meant he was forced to narrow down his career choices.
"I started questioning how I dress … I became a bit socially isolated," he said.
"I couldn't become an electrician … I couldn't go into aviation, the police force or the fire brigade."
He eventually became a nurse, but more than two decades later, he still has moments of self-doubt.
"Some medications are colour coded tablets … so I've just got to be 100 percent sure that I'm getting the right medication out of the right packages," he said.
"It's always an issue in the back of my mind.
"I've always been interested to know how other people see colour."
- ABC