Frame inserts are a type of eyewear accessory that are used to hold LENSES in place. They are typically made of plastic or metal and come in a variety of shapes and sizes. The term 'frame inserts' can also refer to the small pieces of material that are inserted into the frame of glasses to provide extra support for the LENSES. Lens inserts are an important part of eyewear, as they help to ensure that the LENSES stay securely in place and do not move around when worn.