eye glass holders

Where can I get something to keep my glasses on while I am climbing.

Drug store, supermarket, eye Dr.'s, or make your own with a length of Zing-it or other such cordage.

Thank you. All I could think of was Duct tape. I do not think that would be comfortable at all.

Something I love using, ( when I remember to ! ) are these shop goggles that are made specifically to fit over eye glasses. Best part, there CHEAP ! Like $1.50 cheap ! I found em at Harbor Freight tools. They do dual duty...they protect my glasses from debri and assorted damage, as well as keep em on me. They don't come with a strap...they have the folding bows, and truth be told, they don't go over all styles. One difficulty for me, in trying to use 'croakies' is that my glasses are of the flex variety, so strap styles make my glasses flex, and distorts my view. However, the frame of these over glasses is more rigid, so I'm gonna try and put a strap on them.