What is a chalazion?

A chalazion is a small swelling or lump in the eyelid. It may start as a small, red, tender area in the eyelid. Days later, it may change to a painless lump in the eyelid.

A chalazion is similar to another bump that can appear on the eyelid called a sty. Unlike a chalazion, a sty is caused by a bacterial infection in the root of the eyelash and the bump appears at the edge of the eyelid. Sometimes a chalazion can begin as a sty on the inside of the eyelid. A sty is painful; a chalazion generally is not. Also, a chalazion appears farther back on the eyelid. Treatment for both conditions, however, is similar.

What causes a chalazion?

A chalazion occurs when the opening of an oil-producing gland in the eyelid becomes clogged. Oil-producing glands line the eyelids and help lubricate the surface of the eye. When the opening of the gland becomes blocked, oil backs up inside the gland, causing the eyelid to swell. After the initial redness and swelling go away, a firm lump forms in the eyelid.

What are the signs and symptoms of a chalazion?

Signs and symptoms of a chalazion include:

  • Painless swelling in the eyelid that slowly grows over the first week
  • Swelling of the membrane that covers the surface of the eye and inner surface of the eyelid (conjunctiva)
  • Blurred or distorted vision
  • Red or grey area on the inside of the eyelid

Last reviewed by a Cleveland Clinic medical professional on 12/27/2017.


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  • Merck Manual Consumer Version. Chalazion and Stye (Hordeolum). Accessed 12/27/2017.
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