Eyeglass holders, also known as eyeglass frames, are the part of eyeglasses that hold the lenses in place. They come in a variety of shapes and sizes and are typically made of metal or plastic. The most common type of eyeglass holder is the rim, which is four letters long. RIMS are usually made of metal and have a curved shape that fits around the lenses. They provide support to the lenses and help keep them in place.