Not just when you want something unique. But especially if you have a specific face and complex corrective defects. With high diopters, the lenses are relatively thick, so it is necessary to optimize the eyewires to make the lens fit as best as possible, and to create a frame thick enough to completely enclose it.

3D print can make the frames even lighter thanks to the material and also possibility to hollow the frames.

These glasses were designed for -23D lenses with 9mm thickness.