Random spot checks, similar to breath tests for alcohol, are one system senior officers are considering for a scheme which could begin this autumn.

But the details of how eyesight regulations will be enforced have yet to be finalised, said the Association of Chief Police Officers (Acpo).

Police have also suggested that the eyesight regulations for drivers should be stricter, and cover all aspects of eyesight.

Drivers' vision

It is a criminal offence to drive a motor vehicle if you cannot read a standard number plate in good daylight from 20.5m (67 feet), using glasses if necessary Source: DVLA

West Mercia Police had already run a pilot involving spot checks and the project will have to be assessed before it is rolled out nationally, said a spokesman for Acpo.

Recent NOP research for Specsavers Opticians found that as many as 3.5m people could be driving with eyesight below the legal minimum.

Nearly 90% of British drivers believe they should have compulsory eye tests every five years, according to another poll for the chain.

But only 53% would support roadside checks.

David Kenworthy, head of road policing with Acpo and Chief Constable of North Yorkshire Police, said current measures to identify motorists with poor vision were not tough enough.

Drivers' Vision II

If you need glasses or contact lenses to do the above, you must wear them every time you drive There are additional rules if you want to drive vehicles over 3.5 tonnes and minibus/buses Certain eyesight conditions, such as cataracts, glaucoma and double vision, must be reported to the DVLA Source: DVLA

"Since eyesight usually deteriorates slowly and can easily go unnoticed, drivers need to seek professional help rather than rely on their own judgment as to how good their eyesight is," he said.

"We have always maintained that the current eyesight requirement is not rigorous enough and would support the introduction of something more stringent, which fully tested all aspects of vision."

Relatives of a teenager killed by a driver with poor vision backed the campaign.

Backed by families

Emma Holley, 18, was killed by a young driver with "extremely poor" vision in 2000 and her mother Jan Holley, 50, stressed the need for regular eye tests.

UK drivers

3.5m could be driving with vision below legal limit 22% who need glasses have knowingly driven without them One in five cannot see properly at night 3% have never had their eyes tested Optometrists recommend eye tests every two years Source: NOP Research for Specsavers Opticians

"A driver only needs to give up 30 minutes of his or her life every two years to have an eye examination, yet not doing so could rob someone of their life forever," she said.

The survey showed that 87% wanted eye checks for drivers every five years to be made compulsory, especially for people aged 40 and over.

Opticians have called for mandatory eye tests at the scene of an accident.

The research was carried out in June by Access Omnibus Surveys, questioning 2,000 people from across the UK.