Twitter privacy question! ^^

OK so I had Twitter for a while but I just recently made my tweets protected. Well,I had a bunch of followers who I followed back.So, even now that I made them private will those followers be able to see them? I mean I never got their "follow request" because I didn't have a private account...So yeah my vraag - can those followers see my tweets? And if yes - how can I stop them from doing so?