Got some new reading and distance specs. recently. The reading ones are OK as the frames are metal, but I need to 'adjust' the distance ones as my ears are not level by about 5mm (having one that's low is bad enough, but the other one being high just makes it worse).
Now, the 'droid in Tescrot Opticians had a go with a special hot-air thingy and at that point I rather lost trust: first of all, heating the bridge might damage the lenses and also only twisting, therefore putting the lenses out of plane, would work; the second factor was that she was trying it on the metal frames!
The distance pair are black plastic. I've tried v. hot water on a pound-shop pair that are very similar and it has no effect. Is there a way of doing this, or do I have to use a packing piece? In retrospect I should have had meta frames.