quoting:
So that my glasses don't fall off, I attach one of
these sports-bands (I think that's what they're called).

[...]


What are you doing when they fall off?

Glasses, when properly fitted will not fall off or slip under normal
activities. They should fit snuggly to the point if you look down they will
hang nicely on the ears. If they are falling off or slippig under normal
activities, then they are too loose. Go to your eye doctor who sold you the
glasses and have them checked out.