After more than 25 years of searching, neuroscientists in the UK recently announced that they've discovered a woman who has an extra type of cone cell - the receptor cells that detect color - in her eyes.
According to estimates, that means she can see an incredible 99 million more colors than the rest of us, and the scientists think she's just one of a number of people with super-vision, which they call "tetrachromats", living amongst us.
Most humans are trichromats, which means we have three types of cone cells in our eyes.
Each type of cone cell is thought to be able to distinguish around 100 shades, so when you factor in all the possible combinations of these three cone cells combined, it means we can distinguish around 1 million different colours.
Most people who are colour blind only have two functioning types of cone cells, which is why they can only see around 10,000 shades - and almost all other mammals, including dogs and New World monkeys, are also dichromats.
But there's one doctor in northern England who has four cone cell types, taking the potential number of colours she can distinguish up to 100 million - colours most of us have never even dreamed of.
Identified only as cDa29, the scientists finally found this woman two years ago, but they've been searching for more than 25 year - and think there are more tetrachromats like her out there.
Assuming that colour blind men pass this fourth cone cell onto their daughters, Mollon estimated that around 12 percent of the female population
should be tetrachromats.
But all of his tests showed that these women could only perceive the same colours as the rest of us - which meant only three of their cone cell types were working, so they weren't true tetrachromats.
Then, in 2007, neuroscientist Gabriele Jordan from Newcastle University in the UK, who had formerly worked alongside Mollon, decided to try a slightly different test to look for this super-vision.
She took 25 women who had a fourth type of cone cell, and put them in a dark room. Looking into a light device, three coloured circles of light flashed before these women's eyes.
To a trichromat, they all looked the same, but Jordan hypothesised that a true tetrachromat would be able to tell them apart thanks to the extra subtlety afforded to her by her fourth cone.
Incredibly, one of the women tested, cDa29, was able to differentiate the three different coloured circles in every single test.
"I was jumping up and down," Jordan told Veronique Greenwood from Discover magazine.
The research on cDa29 hasn't been peer-reviewed or published as yet, and Jordan is continuing her research and search for more tetrachromats.
There's a lot more work to be done and Jordan's results need to be replicated and verified. But if we can confirm that tetrachromats really do exist, it won't just teach us about the limitations of human senses, it could help scientists develop better artificial sensing devices, and also help us figure out more about how vision works.
One thing we might never be able to understand, sadly, is exactly what the world looks like through cDa29's eyes, seeing as it's our brains that truly perceive colour - our cone cells just receive the data to be processed.
"This private perception is what everybody is curious about," Jordan toldDiscover.
"I would love to see that."