The practical test starts with the eyesight check. If you cannot meet the required standard, the road-driving part does not continue.
You must be able to read the required vehicle registration number at the prescribed distance, using glasses or contact lenses if you need them for driving.
These examples are for understanding and practice; they are not a promise that a particular mistake will always receive a particular grade.
Arriving without the corrective lenses you need to meet the legal eyesight standard.
Being unable to read the registration plate at the required distance.