Medical Equipment Glossary

Often confused with styes, a chalazion is a small sebaceous cyst on the eyelid which appears as a bump on the eyelid. It is caused by the inflammation of a blocked meibomian gland, which is a fat-secreting gland of the eyes. A chalazion differs from a stye (hordeolums) in that a chalazion is usually larger than a style, and it is generally painless except for the tenderness which is caused as it swells. A chalazion may eventually disappear on its own after a few months, but usually requires some treatment.