Motorists over the age of 80 need to take regular eye tests to ensure they can see well enough to drive, research has suggested.
The study centred on a law on Florida that required octogenarians to pass a vision test before renewing their drivers" licence.
It linked the fall in death rates from vehicle collisions in this age group to the new legislation.
The authors wrote that the over-80s is the fastest-growing group in the driving population of the US and their rate of accidents had raised public concern.
"Research has suggested that this increase may be partly attributed to medical, functional and cognitive impairments," the continued.
Around 93 percent of the over-80s who sought to renew their licence were able to.
This could mean only a small percentage of drivers failed to meet vision standards or that those who did went on to seek vision correction in the form of glasses or contact lenses, the study concluded.
The NHS currently recommends people have an eye test every two years at minimum.
by Emily Tait