A police crackdown on drivers with defective eyesight has been launched.
Every motorist stopped by officers from three forces in September will be required to read a numberplate from 20m away.
Anyone who fails will have their driving licence immediately revoked.
Data from the tests will be used to improve understanding of the extent of poor driver vision.
The initiative is being run by forces in Thames Valley, Hampshire and the West Midlands, and is supported by road safety charity Brake and optician firm Vision Express.
Officers can request an urgent revocation of a licence through the DVLA if they believe the safety of other road users will be put at risk if a driver remains on the road.