What to do with old spectacles...?

Hello peeps. I wear specs and usually update my prescription every 2 years. This means I have quite a few sets of quality spectacles laying around in the desk drawer that I no longer use. This got me thinking: there must be heaps of people who can't afford specs who could benefit from some free ones. Where can I donate these specs? It must be to some organisation that gives them out for free. People must NOT have to pay for them! I'm in Auckland.

Any ideas welcomed, thanks.