A method for modifying the refractive index of an optical polymeric material. The method comprises continuously irradiating predetermined regions of an optical, polymeric material with femtosecond laser pulses to form a gradient index refractive structure within the material. An optical device includes an optical, polymeric lens material having an anterior surface and posterior surface and an optical axis intersecting the surfaces and at least one laser-modified, GRIN layer disposed between the anterior surface and the posterior surface and arranged along a first axis 45° to 90° to the optical axis, and further characterized by a variation in index of refraction across at least one of at least a portion of the adjacent segments and along each segment.