The human body is a complex machine which we're all still learning about as we go - and it turns out checking in with your pals about the abilities of your skin suit might lead to some interesting revelations.
Social media users have been left shocked after Dr Sermed Mezher stitched a TikTok video of a bloke who explained he thought 'everyone' could carry out a strange phenomenon with their eyes to let him in on a secret...that we can't all do it.
The medic, better known online as @drsermedmezherexplains, often shares useful health advice to educate his followers, such as common signs of ADHD, why you can never feel a mosquito bite and why we should forget the 'five second rule'.
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And in one of his recent videos, he revealed that about half of the population have a secret 'superpower' - before adding that unfortunately, it's 'less useful than a bottle flip'.
However, it's still pretty cool and Dr Mezher reckons it is 'neurological curiosity that showcases the variability in human motor control and sensory perception'.
So, what is this strange, but apparently useless, skill?
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Blurring your vision on command or unfocusing your eyes at will, of course.
Dr Mezher explained this 'rare and intriguing ability' is a similar phenomenon to how some people can only raise one eyebrow, whereas others are only able to wiggle both at once.
He told baffled social media users: "This phenomenon involves consciously relaxing the eye muscles that control focus, allowing individuals to defocus their vision at will.
"The ability to blur vision is typically achieved by relaxing the ciliary muscles, which control the shape of the lens, and thus the focus of the eye. When these muscles relax, the lens becomes less curved, causing the image on the retina to blur."
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Who knew? I certainly didn't, as I'm sadly not a member of the blurry eyed brigade.
The doctor said that people who possess the ability to unfocus their vision whenever they like often compare it to daydreaming, staring into space or zoning out.
He explained that artists often speak of benefiting from it, as they 'use it to gain extra perspective on an image'.
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"It's a skill that can be learned and refined with practice, though it may come more naturally to some individuals than others," Dr Mezher continued.
"This ability can be useful in certain situations, such as when trying to reduce visual strain during prolonged periods of close-up work or reading.
"However, the capacity to blur vision voluntarily doesn't appear to be related to any specific visual or health advantages.
"The ability to defocus your eyes on command is a natural one, but not everyone can do it."
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But the social media medic reckons that those who can't do this instinctively can 'achieve a similar effect' by changing their focus from an object nearby to a distant one, or crossing their eyes.
Dr Mezher's followers were left stunned by the revelation - although some were quick to brag that they could do it - and flooded the comment section with their thoughts.
One said: "I thought everybody could do this?!"
Another added: "It's like moving your ears. Some people just can't find the muscle to move it."
A third chimed in: "I can't do it!"
While a fourth joked: "I can immediately blur my vision by taking off my glasses."