I have several pairs of glasses, I counted them up and there are 8 pairs in all.
Some for reading, some downstairs, another pair in my bag and some upstairs. Saying this I still often can't find a pair, lol
Over time the arms become tired and tend to spread out therefore making the glasses slip down my nose. Tom had tightened the screws but basically they are just getting old.
I have found a solution to this by taking two tiny bits of cardboard and putting them inside the hinge part of the glasses, this tightens them up and they do not slide down my nose.
When we went to the cafe the other day I took my glasses out of my bag and didn't have any cardboard.
Being a resourceful person I found a replacement the did the job nicely.