UV curable coating composition includes a non hydrolyzed epoxy- alkoxy-silane, polyfunctional acrylate and/or epoxy compounds and a cationic and/or free-radical photo-initiator; with polyfunctional acrylate and/or epoxy compounds representing more than 40 weight % of the total dry matter and the composition being without any hydrolyzed epoxy-alkoxy-silane. This composition is coated and cured on an optical substrate.