A system for improving vision of a subject, the system comprising: at least one sensor configured to determine a correction to be made to an intraocular lens to correct chromatic aberration, wherein the IOL has a first index of refraction; a control system operatively coupled to the at least one sensor and configured to receive associated sensed data corresponding to the correction to be made to the IOL and to calculate, based on the sensed data, at least one of: shape and/or index of refraction for at least one additional layer to be formed within the IOL, the additional layer having a different index of refraction than the first index of refraction and a particular shape within the IOL configured to improve the vision of the subject; and parameters for a pattern of laser radiation to be applied to at least one selected area of the IOL to form the at least one additional layer; and a radiation system operatively coupled to the control system and configured to, based on control by the control system, apply focused laser radiation according to the parameters and pattern of laser radiation to be applied to at least one selected area of the IOL, to form, within the IOL, the at least one additional layer having the different index of refraction and the particular shape; wherein the at least one additional layer comprises more than two additional layers, each of the more than two additional layers having a respective index of refraction and being formed with a particular shape within the IOL, the more than two additional layers comprising at least two different shapes; wherein the more than two additional layers are not diffractive and are purely refractive. at least one sensor configured to determine a correction to be made to an intraocular lens to correct chromatic aberration, wherein the IOL has a first index of refraction; a control system operatively coupled to the at least one sensor and configured to receive associated sensed data corresponding to the correction to be made to the IOL and to calculate, based on the sensed data, at least one of: shape and/or index of refraction for at least one additional layer to be formed within the IOL, the additional layer having a different index of refraction than the first index of refraction and a particular shape within the IOL configured to improve the vision of the subject; and parameters for a pattern of laser radiation to be applied to at least one selected area of the IOL to form the at least one additional layer; and shape and/or index of refraction for at least one additional layer to be formed within the IOL, the additional layer having a different index of refraction than the first index of refraction and a particular shape within the IOL configured to improve the vision of the subject; and parameters for a pattern of laser radiation to be applied to at least one selected area of the IOL to form the at least one additional layer; and a radiation system operatively coupled to the control system and configured to, based on control by the control system, apply focused laser radiation according to the parameters and pattern of laser radiation to be applied to at least one selected area of the IOL, to form, within the IOL, the at least one additional layer having the different index of refraction and the particular shape; wherein the at least one additional layer comprises more than two additional layers, each of the more than two additional layers having a respective index of refraction and being formed with a particular shape within the IOL, the more than two additional layers comprising at least two different shapes; wherein the more than two additional layers are not diffractive and are purely refractive.