I have written a bit about a mobility scooter for my husband on this subject. He has macular degeneration in the left eye, this has been halted with treatment and has been driving like that for about two years, but his licence ran out in June, and early this year the DVLA reminded him of this and he had to fill in all the details of medication etc. They had already been advised of the macular problem. After 90 days - the time DVLA take to sort these things out he was asked to visit the optician chosen by them, but that he could continue to drive, using the letter of authority sent with the appointment. The optician advised him that his eyesight was borderline for driving, a catarract in the other eye not helping at all, but that the DVLA would let us know. My husband continues to drive for the simple reason he has not been told not to, as the optician did not say he should not, but he still only has the letter of authority, no proper driving licence.