One in ten British motorists would fail to meet the legal standard for eyesight, claimed direct motor insurer Asda.
There are currently around 3.5 million drivers on Britain's roads who can't see properly, with one in ten never having had their eyes tested, said Asda.
It said drivers with bad eyesight contributed to over 320,000 road accidents and over 5 million motor insurance claims a year.
The company said it had started a "Safe Sight" campaign to highlight the issue, and is offering reduced cots eye tests in its supermarkets.
Asda director of financial services, David Rutley, said: "There are enough hazards on today's roads without poor eyesight adding to them. More 20/20 vision on our roads means fewer accidents and fewer insurance claims, helping to keep the cost of insurance low."
