What is a sty?
A sty is a painful, red bump that forms on the edge of your eyelid. It may look like an acne pimple. The medical term for a sty is hordeolum (say: hor-dee-oh-lum).
A sty forms when bacteria get into the root of your eyelash (also called the follicle). This causes the oil glands in your eyelid to become blocked and infected. Sties may cause discomfort, but they are not usually serious and are easy to treat. They are very common, especially in children.
What eye problems are similar to sties?
A chalazion (say: keh-lay-zee-on) is a firm (but less painful) bump in the middle of the eyelid. It is caused by an inflamed, blocked gland. A chalazion may also cause blurry vision. Treatment for a chalazion is similar to treatment for a sty; however, the bump may not go away for 2 to 8 weeks.
Written by familydoctor.org editorial staff