Abstract: Multiple index optical structures, including doublet and triplet lenses, aspheres, torics, atorics, and other types of freeform multiple-index lenses, may be 3D printed as single components from a variety of optical materials having different indices of refraction. 3D-printed Multiple-index lenses may be printed onto other lenses, optical structures, or light emitting structures, or onto components of an electrical optical system to provide color correction and reduced distortions while reducing system complexity by requiring fewer lenses and reducing production costs by reducing the processing power and memory required to maintain system latency. A related method modifies the radiation pattern of an LED assembly by 3D printing optical material directly onto an LED die or an LED emitter bulb.