An accommodating intraocular lens, comprising: an outer lens enclosure having an anterior structure, comprising an anterior outer surface configured to reside adjacent an interior anterior surface of an evacuated capsular bag and an anterior inner surface, and a posterior structure, comprising a posterior outer surface configured to reside adjacent to an interior posterior surface of the evacuated capsular bag and a posterior inner surface, the anterior structure and the posterior structure of the outer lens enclosure extending to and being joined at an equatorial zone of the intraocular lens; a first inner portion having an anterior zone and a posterior zone, an anterior surface of the anterior zone and a posterior surface of the posterior zone of the first inner portion being disposed, respectively, adjacent to the anterior inner surface and the posterior inner surface of the outer lens enclosure; and a second inner portion disposed between the anterior and posterior zones of the first inner portion, having an anterior zone and a posterior zone, the anterior and posterior zones of the second inner portion being adjacent to the first inner portion; and an innermost member disposed between the anterior zone and the posterior zone of the second inner portion; wherein the intraocular lens is deformable by ciliary muscle action when positioned in the evacuated capsular bag such that at least the outer lens enclosure, the first inner portion or the second inner portion are deformed by progressively increasing ocular force, the intraocular lens having an unaccommodated state in which the intraocular lens provides a base optical power and an accommodated state in which the outer lens enclosure and the first inner portion, and the second inner portion each provide an add power, characterised in that the refractive indices of the outer lens enclosure, first inner portion, second inner portion, and innermost portion progressively increase from the outer lens enclosure to the innermost portion. an outer lens enclosure having an anterior structure, comprising an anterior outer surface configured to reside adjacent an interior anterior surface of an evacuated capsular bag and an anterior inner surface, and a posterior structure, comprising a posterior outer surface configured to reside adjacent to an interior posterior surface of the evacuated capsular bag and a posterior inner surface, the anterior structure and the posterior structure of the outer lens enclosure extending to and being joined at an equatorial zone of the intraocular lens; a first inner portion having an anterior zone and a posterior zone, an anterior surface of the anterior zone and a posterior surface of the posterior zone of the first inner portion being disposed, respectively, adjacent to the anterior inner surface and the posterior inner surface of the outer lens enclosure; and a second inner portion disposed between the anterior and posterior zones of the first inner portion, having an anterior zone and a posterior zone, the anterior and posterior zones of the second inner portion being adjacent to the first inner portion; and an innermost member disposed between the anterior zone and the posterior zone of the second inner portion; wherein the intraocular lens is deformable by ciliary muscle action when positioned in the evacuated capsular bag such that at least the outer lens enclosure, the first inner portion or the second inner portion are deformed by progressively increasing ocular force, the intraocular lens having an unaccommodated state in which the intraocular lens provides a base optical power and an accommodated state in which the outer lens enclosure and the first inner portion, and the second inner portion each provide an add power, characterised in that the refractive indices of the outer lens enclosure, first inner portion, second inner portion, and innermost portion progressively increase from the outer lens enclosure to the innermost portion.