A process is described for manufacturing an ophthalmic lens containing a Fresnel microstructured surface inside the lens. The Fresnel lens is injection molded with a mold insert having a heat conductivity lower than the thermoplastic material used to form the Fresnel lens. A second thermoplastic material is overmolded to the Fresnel lens to cover and protect the microstructured surface. The mold insert is made from nickel or a thermoplastic material. The resulting lens includes two layers having different refractive indices. The Fresnel lens may be made from polycarbonate while the overmold may be made from a poly(methyl methacrylate) or a thermoplastic polyurethane.