I currently own one pair of glasses, having accidentally stepped on my second pair a few days ago. I therefore went into town to purchase a new second pair. Before doing so, I obtained the details of my prescription from the company that carried out my last eye test. This was so I would not have to pay for another eye test. (The pair of glasses I currently own have the prescription from my last eye test, and I am able to see through these perfectly well.)
However, after selecting a pair of frames, and handing over the details of my prescription to the salesperson, I was told that my prescription is no longer valid. In particular, I was told that it would be illegal for the company to sell me any glasses because my last eye test was carried out too long ago (namely, >1 year ago). I explained that the glasses I currently wear have the prescription from my last eye test, and that I can see through these without any trouble. But I was told--regardless of my judgement--that the company could not sell me a pair of glasses without first ascertaining my up-to-date prescription through another eye test. Apparently, the law prohibits retail stores from selling glasses based on prescriptions from eye tests carried out >1 year ago.
I immediately joked that this law must have been written by the administrators of eye tests, and the salesperson agreed. Of course, I'm sure the law's advocates argued that the law is in the interests of the poor, helpless consumer--someone who couldn't possibly work out whether or not his old prescription is good enough. One thing I don't understand is how internet retailers get around the law. Indeed, there seem to be many websites offering glasses based on prescriptions provided by the customer--some with '.uk' addresses. An alternative explanation is simply that I was hustled by a crafty salesperson!