A chalazion and a stye are both infections of the edge of the eyelid, but they have some key differences: Chalazion: A chalazion is a less painful, chronic infection that affects the Zeis or meibomian (oil-secreting) glands on the conjunctival side of the eyelid. It is caused by a clogged oil gland and is usually not painful. A chalazion can sometimes grow large enough to cause blurry vision if it presses on the eye. Risk factors for chalazia include acne rosacea, chronic inflammation of the eyelids, poor eyelid hygiene, and meibomian gland dysfunction.
Stye (Hordeolum): A stye is a painful infected lesion that appears on the edge of the eyelid (eyelash follicles) and comes on quickly. It is usually caused by an infected eyelash root and can result in swelling, pain, and tenderness of the eyelid. Styes are contagious and more tender to the touch than a chalazion. If a stye is present for several weeks, it may develop into a chalazion. Treatment for both conditions may include warm compresses, antibiotics, corticosteroid injections, or incision and drainage procedures, depending on the size, location, and persistent nature of the infection. It is important not to attempt to remove a stye or chalazion yourself, as it could cause the infection to spread. If you suspect you have either a chalazion or a stye, it is recommended to consult with an eye care professional for proper diagnosis and treatment.