THIS mind-bending optical illusion hides a secret inside – and it’s one that’ll tell you something very important about your eyes.
Thousands of people have puzzled over the visual trick, which poses a simple question.
But bizarrely, many have come to completely different conclusions on the hidden figures in the drawing.
The illusion shows a series of numbers in a striped black and grey circle.
It was posted on Twitter by user @benonwine, who asked: “Do you see a number?
“If so, what number?”
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One puzzler responded: “45 283… and what’s the catch?
“Should I book an appointment with my GP?”
Another posted: “I can only see 528.
“Does that mean anything about my eyesight?”
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A third wrote: “I can see 45283, since looking at the other replies I’ve others are seeing two other numbers.
“I can see there are numbers there but can’t make them up.”
In fact, there are seven numbers in total – 3452839.
The trick works by playing on contrast sensitivity, which is an important measure of visual function, Mail Online reports.
It’s allows us to perceive the difference between objects and their backgrounds, and we use it all the time in real life – for example, when driving in low light or fog.
Those with higher levels of contrast sensitivity are more likely to have been able to see all seven digits straight away.
Poor contrast sensitivity can be a symptom of eye conditions including cataracts or glaucoma.
It might be helpful to view the puzzle from further away, allowing the eye to adjust.
There are three main classes of optical illusion – and one of the types, cognitive, can tell us something about how we think.
An image designed by Gala Spins shows either a yellow butterfly – or two people talking to each other.
Some 71 percent of those who viewed the image see the butterly, while 29 per cent see the faces.
Bhavin Shah, an optometrist at Central Vision Opticians, explained why we see different things.
CATCH YOUR EYE
“Many people will see the butterfly first, before zeroing in on the detail of the faces,” he said.
“Humans have a propensity to human faces and are always drawn to them.
“There are parts of the brain that respond specifically to faces so once we’ve seen it in the illusion, we’ll tend to see that more.”
Some neuroscientists believe we have special relationships to faces, as we have regions of the brain specifically dedicated to processing them.
Meanwhile, another optical illusion has left viewers baffled as circles appear to vanish before their eyes.
Read More on The Sun
A “simple, yet brilliant illusion” has left viewers stumped as they cannot guess what’s behind the image.
And this hollow mask illusion can say a lot about how your brain is wired.