Where can I buy Boric Acid as used for Pink Eye or a Sty?

Back when I was a child my mother had boric acid at home, used for pink eye or an infection. You would boil water put a spoonful or so in the boiling water and wet a wash cloth and let it soak on your eye or wound to help kill the infection. I have tried a local CVS and Walgreen's and they didn't even seem to know much about what I was talking about?? So I'm hoping someone out there can help! Thanks!