SteveB wrote:
Take them where you bought them. They may prefer some way, i.e. Loctite,
SuperGlue, clear nail polish.

They look like the three pair I have. If his source was like mine,
a drugstore, the staff likely won't be of much help. Green Loctite
did the job for me. Just a tiny bit applied with a broomstraw to the
threads emerging from the nuts. Don't overdo it.

There may be some reason that one of the
things suggested here might not work well, like discoloring the metal,
eating up any plastic it touches, etc. Something that one would not
normally think of, but in this application would be critical or detrimental
enough not to be a consideration. If it were just a nut and bolt, there
could be lots of suggestions that would probably work. Since this is a tiny
item, with unknown coatings, and unknown properties, if it were me, I'd take
it to where I bought it. They may even have a tube of GlassGoo or something
that is made specifically for that.

BTW, I have three pairs of titanium glasses, and there's nothing better.
But I do have to watch those little screws.

Steve