As a minimum legal requirement, motorists must be able to read a number plate from a distance of 20.5 meters (67 feet) and have a 120 degree wide field of view. This test is normally only carried out officially at the time of the driving test itself and recent research has shown that more than 10 per cent of drivers would fail a driving test if they re-took it today because of poor eyesight.
To view more, visit http://www.eyecaretrust.org.uk/view.php?item_id=3