The present invention relates to a method of manufacture of an optical lens providing refractive index modulation, characterized in that, starting from a lens of transparent hydrophilic polymer preferably of the hydrogel type, which has previously been shaped, the lens is impregnated with a photopolymerizable composition containing at least one monomer and a photoinitiator, which are in solution in water in the case of a hydrogel, the impregnated lens is subjected to locally modulated irradiation so as to cause local selective polymerization of the monomer, whereupon the excess non-hardened photoinitiator and non-pulverizable monomer is removed.