A quarter of drivers haven't had an eye test in the last two years. Is your vision putting yourself and other road users in danger? Motoring journalist Maria McCarthy takes a closer look.
Many people who wear glasses or contact lenses do so from childhood.
Others realise they need them when the small print starts getting, well, smaller, and they make an appointment with an optician.
But discovering that you need glasses for driving can be a different matter.
Discovering you need glasses when driving
Often people need to be told by others rather than noticing it themselves.
Jenny, 50, from Oxford, often argued with her now ex-husband about how she felt he needed driving glasses.
"He used off-the-peg reading glasses for close work and wouldn't accept he might need prescription glasses for driving.
"But he frequently missed road signs and I was very worried about his driving.
"Finally he did go to the opticians and was prescribed driving glasses which he does now wear, thank goodness."
Motorists driving with impaired vision
But the problem of motorists driving with impaired vision is an ongoing one.
Sharpen Up is a new campaign launched by road safety charity Brake.
The charity is working alongside the DVLA, insurer RSA, which owns car insurance firm More Than, and high-street optician Specsavers.
The campaign is calling on all drivers to ensure their vision meets legal standards and that they aren't putting themselves or other road users in danger.
26% of drivers haven't had eye test in last two years
A survey of 1,000 drivers carried out for the campaign revealed that a quarter of them - 26 per cent - haven't had an eye test in the last two years.
Meanwhile, 9 per cent of drivers admit to not visiting the optician for five years or more and 3 per cent have never been.
It also revealed that 9 per cent of the motorists who know they need glasses or contact lenses for driving don't always wear them.
Jan Chandaman is head of medical licensing policy at insurance group RSA.
She says: "All drivers are required by law to meet the appropriate eyesight standard at all times when driving and failure to do so is an offence."
No legal requirement for driver vision checks
Currently, after the "please read the numberplate" part of the driving test, there is no legal requirement for drivers to have their vision checked regularly.
Instead the DVLA is dependent on drivers themselves or third-parties to report vision defects.
Even if motorists feel confident that they could pass 'the test' of reading a numberplate from 20 metres away, this still can't pick up on defects in visual fields.
The Sharpen Up campaign urges drivers to have their sight tested at least once every two years or sooner if they notice problems.
It wants the government to introduce a requirement for drivers to provide proof of a recent visit when applying for their provisional licence and for every licence renewal after that.
Regular eye exams 'vital'
Specsavers optician Raj Kukadia agrees that regular checks are vital for all motorists.
He says some people might realise they need glasses because of eye strain or headaches.
But he adds that others can be symptom-free but still suffering from impaired vision that makes them unsafe on the road.
Kukadia says that as people age, they might need different glasses for close work and for driving.
Different prescriptions for different activities
"In younger people the lens is more elastic and can adapt so one pair of glasses can be sufficient, but older people might need different prescriptions for different activities.
"It's also important for motorists to choose anti-reflective coatings for their glasses.
This makes it easier to drive at night as dazzle from oncoming headlights or street lights will be reduced."
And, of course, some people prefer to use contact lenses to correct their vision.
"There are different types and your optician will explain which is right for you," says Kukadia.