Patent ID: 6913357

Claim:
A method of manufacturing plastic photochromic lenses comprising: obtaining a lens by polymerizing and curing a monomer mixture comprising at least: one of a monofunctional and bifunctional methacrylic ester monomers in an amount of at least 50 weight percent of the monomer mixture: a trifunctional or greater methacrylic ester monomer in an amount of 1 to 30 weight percent of the monomer mixture; and at least one photochromic dye; directing radiation comprising ultraviolet radiation of a wavelength of less than or equal to 300 nm onto at least a portion of a surface of the lens obtained so that the radiation activates the surface of the lens to break down macromolecular chains of the surface of the lens; coating a composition onto the at least a portion of the surface of the lens that has been exposed to said radiation, the composition comprising: an organic silicon compound comprising at least one alkoxy group and at least one epoxy group; and a colloidal metal oxide; and curing said coating to obtain a hard surface film.