Thank you. The prescription glasses would worry me. They would be expensive, for a start. I also had a bad experience with an optician prescribing lenses for using the computer; the glasses were so bad that I couldn't use them and had to ask for my money back. I now go to a different optician but still remember the bad experience. I will look at the other ideas.
My local library has a photocopy enlargement service so I will try that out. Thank you.