Much has been made of the need to wear glasses or contact lenses when behind the wheel, if required, but another danger to vision is now present in the majority of cars, it has been claimed.
According to the results of a recent study carried out by researchers at University of London and Lancaster University, people who have sat-navs installed in their car are far more likely to take their focus off the road, which multiplies the chances of them being involved in an accident.
According to lead researcher Polly Dalton, from the University of London's Royal Holloway college department of psychology, one reason for the distraction may be that sat-navs now have too many functions, which can be time-consuming to program.
This, in turn, results in drivers having to take their focus off the road for longer periods of time – something that was indicated by simulation tests carried out by the researchers, who found that motorists with sat-navs spent far more time taking their eyes off the road than those with no device.
She told the BBC that although people are capable of following spoken instructions in a car and it can be a good way of presenting information to them, there are still risks.
"It's important not to make those directions too complicated because that runs the risk of asking them to keep too much information in mind when they are also trying to concentrate on the driving task," Ms Dalton added.