Frames are manufactured from a variety of materials that vary significantly in quality. Moreover, different manufacturing processes are used. It starts from basic injection moulded plastics, to highly sophisticated handmade organic acetates with manufacturing processes that can take up to six months to complete. Some frames are polished and finished by hand. Hinges and nose pads are applied by hand and require particular processes to ensure correct alignment and fit to the frame.
It is possible to buy 3D printed frames, frames made from wood, recycled paper, and all kinds of other exotic materials. These bespoke materials and processes add dramatically to the cost of the product.