What is true about a chalazion?

A chalazion is specifically characterized by a blockage in one of the oil glands, also known as meibomian glands, located in the eyelid. When these glands become obstructed, it leads to the accumulation of oil, causing swelling or a bump on the eyelid. Unlike an eye infection, which involves bacteria or viruses, or an allergic reaction, which triggers a response in the body's immune system, a chalazion arises from a mechanical obstruction rather than an infectious or allergic process. It is also distinctly different from an eye injury, as it does not result from trauma or physical damage to the eye. Understanding that a chalazion stems from the blockage of oil glands is crucial for proper diagnosis and treatment.