I discovered recently that Costco’s optical department collects old prescription eye glasses for the Lion’s Club. I just dropped off a bunch there today that we have been accumulating. The Lion’s Club cleans and categorizes the glasses and then has a program for distributing them to needy people in developing countries. You can read more about their program at their site.
The downtown branch of the Chandler Public Library has had a box for them in the past. I’m not sure if it still does. Please leave a comment if you know of other locations that people can drop off their used eye glasses.