Drivers in the UK are being urged to retake their eye tests to ensure their sight meets the minimum requirements for driving.
The call by the DVLA follows a survey that found that 50% of people are unaware what the minimum standard of eyesight for driving is.
Driver must be able to read a numberplate from 20 metres away, roughly the length of five cars, in order to pass the threshold.
Learner drivers are required to do this as part of their practical driving test.
Once qualified, drivers are legally required to ensure their eyesight remains good enough to stay on the road.
Anyone who is unable to pass this test should visit an optician, a senior DVLA doctor advised.
Dr Wyn Parry, said: “The number plate test is a simple and effective way for people to check their eyesight meets the required standards for driving.
“The easiest and quickest way to do this is to work out what 20 metres looks like at the road side – this is typically about the length of 5 cars parked next to each other – and then test yourself on whether you can clearly read the number plate.
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“It’s an easy check to perform any time of day at the road side and takes just a couple of seconds.
“Having good eyesight is essential for safe driving, so it’s really important for drivers to have regular eye tests.”
Eyesight can naturally deteriorate over time, he added, meaning those who have never needed glasses before could eventually require a pair.