This article from GOOD analyzes the impact that buy-one-give-one programs like TOMS and Warby Parker have on communities in developing nations:
"Goods donations are worthwhile when they:
-Meet an immediate need as well as have along term impact
-Are based on actual, observed needs
-Work in partnership with the community
-Support local initiatives
-Good intentions are not enough; in fact, they achieve nothing on their own."
Read more in the article.