A common misconception is that all pilots have to be super fit and have perfect vision but this couldn't be further from the truth. Although it is true you have to have a reasonable standard of fitness you do not have to be a superhero by any stretch of the imagination. In fact, the Civil Aviation Authority (CAA) now allow NPPL pilots and students to have a self-delcaration where you fill in a form on the CAA website where you confirm that you believe you meet the medical requirements for a Group 1 Ordinary Driving Licence issued by the DVLA. In theory, if you are fit enough to drive then you are fit enoguh to fly an aeroplane.
For more information and to fill in the form click here.