Horn-rimme glasses are a type of eyeglasses with frames made of horn, tortoise shell, or plastic that simulates either material. The name horn-rimmed glasses refer to their original material, which was horn or shell. These glasses began to be popular in the United States in the 1910s and 1920s, and have been a standard for many decades. Over time, the glasses changed appearance and meaning. Later, they were known as dark, heavy, and plastic framed glasses. An early plastic, celluloid, was dyed and molded to look like an animal horn.