An optical item comprising an organic or mineral glass substrate (1) and a transparent polymeric material layer (3), characterized in that it comprises at least one intermediate layer (2) in direct contact with one main side of the substrate and the polymeric material layer, the intermediate layer(s) being made of particles of at least one colloidal mineral oxide and optionally of a binder, such (an) intermediate layer(s) having an initial porosity, and the initial porosity of the intermediate layer(s) being filled either by material from the polymeric material layer or by the substrate material if the latter is made in an organic glass and, optionally partly by the binder when present, so that the intermediate layer(s), after initial porosity filling, each represent a quarter waveplate with a wavelength in the range from 400 to 700 nm, preferably from 450 to 650 nm.