Rav Moshe held one does not make a bracha on them. However,Rav Sternburch(Tshuvas v’hanhagos in chelek 5) discusses this and he seems to hold that it is considered a beged aand it is no problem at alll have not seen it in a while though.
Yitay: Whats the problem on shabbas if one holds it is a beged and any beged is a mitzvah D’orasia?