Wearing a tiny portrait of your lover’s eye on your jewelry was a secretive romantic gesture in the 18th and 19th centuries. When the Prince of Wales fell in love with a catholic widow and proposed by sending her a locket with a painting of his eye inside, it wasn’t long before it became a popular trend to wear ‘Lover’s Eye’ jewelry on your wrist or near your heart to symbolize the love you have for another. Source Source 2