A chalazion (plural: chalazia) is an inflammation of the deep oil
glands inside the eyelid. It develops over 2 to 3 weeks, forming a firm lump
under the skin of the eyelid, sometimes with inflammation and swelling.
Often the cause of a chalazion is not known. It may develop from an
internal gland infection that does not drain and heal, or from a blocked oil
gland. It can also develop from rubbing the eyes or using products near the
eyelid that can irritate the eye.
Home treatment is usually all that is needed for a chalazion. This
includes not wearing eye makeup or contact lenses; applying warm, wet
compresses to the eye area; allowing the chalazion to break open by itself; and
using nonprescription medicines. If the chalazion interferes with vision, it
may need to be cut open (lanced) by a doctor.