Slim, flat and thin ophthalmic lenses are becoming more and more popular all over the world. To meet this requirement, Y&S Optical Division developed new molds and tools in 2003. Since early 2004, full series of CR-39 Hard Resin Lenses (both single vision lenses and bifocal lenses), 1.56 Middle Index Hard Resin Lenses and Mineral White 1.523 Ophthalmic Lenses from Y&S are with new Slim design. If compare with old or normal products, the new Slim lenses are much thinner and flatter, both cure and thickness have been deduced.