Driving in the rain, good eyesight is not enough

The optical illusion that went viral on social media started out as a fun pastime, but it's actually quite useful.

Eye test illusion leaves many people confused

Social media users are having a hard time figuring out the hidden numbers in an optical illusion posted on X. It features a black and white striped circle with hidden numbers inside. The stripes go in different directions, making it difficult for viewers to decipher exactly what the numbers are.

But that didn't stop tens of thousands of people from leaving their solutions below the post.

“Do you see the numbers? What are they?” the poster wrote.

"45,283… and what does that show? Should I make an appointment with my GP?" one social media user guessed.

A person who says he can only see a few numbers is wearing corrective lenses.

Another said: "I can see 45,283, because looking at other people's answers… A lot of people are seeing other numbers. I know the number is there but I can't see anything."

"3,452,839, but honestly the first 3 numbers are just guesses. Can't say for sure. It's easier to see if you shake the image up and down, but I don't know why," another pointed out.

One person said: "It was 15,283 at first, then I zoomed in and it became 3,452,839!".

Driving in the rain requires more than just good eyesight

The above optical illusion is related to a concept called “contrast sensitivity”. It is basically the ability to distinguish an object from its background or from one object to another. This is how we can see the difference between black and white.

This is different from a regular vision test. Just because someone has 20/20 vision does not mean they have good contrast sensitivity.

Contrast sensitivity is a very important measure of visual function, especially in low light/glare situations, foggy or wet and blurry conditions. In such cases, the contrast between objects is reduced, making it more difficult for the viewer to distinguish object outlines.

Driving at night or driving in the rain are good examples of activities that require good contrast sensitivity for safety.

Or there are cases of tripping because the stairs or sidewalks have a color similar to the road surface, creating the illusion of walking on a straight line.

Therefore, experts warn that people with reduced contrast sensitivity should avoid driving when it is foggy, rain blurs the windshield or the sun is harsh.

If you can answer the number 3,452,839 correctly without using any tricks, drivers can be confident in their observation skills.