Are you a safe driver, even in the rain? This puzzle can find out

Winter is here, bringing with it the challenges of navigating rainy days.

An optical illusion that went viral on social media can help assess your vision's adequacy for driving in harsh weather conditions. It does this by testing your contrast sensitivity, a crucial factor affecting driving ability.

Contrast sensitivity measures the contrast required for visual object or pattern identification — such as discerning a gray object against a white backdrop or spotting a white object on a light gray background. People with low contrast sensitivity may struggle with things like recognizing traffic lights or cars during while driving at night. A 2021 study in Israel revealed that drivers experiencing reduced contrast sensitivity face a higher risk of traffic accidents.

Despite concerns, Israeli drivers aged 40 and above are no longer obligated to undergo periodic eye tests, a regulation canceled by Israel Katz six years ago against the advice of eye experts. Presently, drivers only need to pass medical tests, including an eye examination, starting at age 70. Professional drivers, like taxi, truck, and bus drivers, undergo testing from the age of 60. Consequently, people can drive from the age 17 to 60-70 without a single eyesight test.

Factors identified in the study as predictive of road accidents in drivers aged 70 and above, such as contrast sensitivity, are not measured at all.

Testing your eyesight: How is your contrast sensitivity?

The optical illusion features a black-and-white circle concealing numbers, with contrasting lines making it challenging to decipher the hidden digits. If you could spot the full number, 3,452,839, your contrast sensitivity is high.

High contrast sensitivity enables the recognition of clear outlines, small objects, and subtle differences in shading and patterns. People with low contrast sensitivity may struggle while driving in challenging weather conditions. As such, they are advised to avoid driving in rain, fog, or in overly sunny weather.

While the optical illusion provides a glimpse into contrast sensitivity, it's not a substitute for a comprehensive test by a licensed optician, especially for older individuals.

Generally, around the age of 40, an eye test with an optometrist is recommended to rule out abnormal vision possibilities. License renewal tests are conducted by qualified optometrists approved by the Transportation Ministry.