People receiving certain benefits get free nhs glasses. But if you fancy something a little better, ASDA have cheaper good frames, and a gives a very good service. You do get free eye tests after 60.
i had my eyes tested at asda once and after receiving the glasses had a lot of difficulty seeing out of them, i spoke to several people at work about it, (i used to work at asda) and it came to light that the optician wasnt qualified at all!