Optical illusions have long intrigued and baffled people, challenging their perception and vision. A recent optical illusion making waves online is no exception. Despite its apparent simplicity, it has left many viewers puzzled and debating what they actually see.

The Hidden Number Illusion

Optical illusions vary in form—some hide the answer in plain sight, while others challenge our perception in more subtle ways. This particular illusion falls into the latter category, testing how well viewers can distinguish contrasting colors. At first glance, it seems straightforward, but as you focus more on the image, the hidden details begin to emerge, making the answer surprisingly elusive for many.

Take a look at the illusion yourself. Can you spot the hidden number in the striped black and grey circle?

The challenge, which has gone viral on Twitter, invites viewers to find a number concealed within the pattern. Though it may look simple, the illusion is a clever test of contrast sensitivity—the ability to discern objects from their background, a skill crucial for tasks like driving in low-light or foggy conditions.

So, how well can you distinguish the numbers?

Conflicting Answers

Before revealing the correct answer, let’s take a look at what others have seen:

• “I can only see 528. Does that mean something about my eyesight?” – @CookieLousie
• “I see 528 with glasses and 45283 without… I can’t read a screen without glasses though.” – @Techn0phobe
• “45283… and what’s the catch? Should I book an appointment with my GP?” – @PhilippeAuclair

Most viewers spotted 528 or, at best, 45283. But the actual answer might surprise you.

The Real Answer

The complete number hidden in the illusion is 3452839—a seven-digit number. Many people only saw the digits near the center, where the contrast is highest. As the numbers spread outward, the contrast between them and the background diminishes, making the outer digits harder to see. But with enough focus—or a squint—you might just catch a glimpse of them!

If you managed to see the entire number, congratulations—you likely have excellent contrast sensitivity! Challenge your friends and family with this optical illusion and see how sharp their eyesight is.