A sty, also known as a hordeolum, is a tender red bump on the edge of the eyelid that is caused by an infection of a gland of the eyelid. The infection is most often caused by a bacteria or germ called staph (Staphylococcus aureus)
. The oil-producing glands line the eyelids and help lubricate the surface of the eye. Styes generally aren’t contagious, but small amounts of bacteria can be spread from them. It is important to always wash your hands before and after touching a stye and avoid touching it to reduce bacteria spread and irritation
