A chalazion is a cyst in the eyelid that is caused by inflammation of a blocked meibomian gland, usually on the upper eyelid. Chalazia differ from styes (hordeola) in that they are subacute and usually painless nodules. They may become acutely inflamed, but unlike a stye, chalazia usually sit inside the lid rather than on the lid margin.


Common symptoms (which may vary) include: swelling on the eyelid, eyelid tenderness, and sensitivity to light, increased tearing and heaviness of the eyelid.