I have bad eyesight and can wear either glasses or contact lenses. When I'm wearing my contact lenses and have trouble seeing something I will try to push my glasses up my nose even though I'm not wearing them.
Equally, if I've been wearing my lenses for a few days and then go back to my glasses and find I can't see properly, I blink rapidly a few times to try to rehydrate my lenses. Generally that doesn't move the dirt on my glasses