A Chalazion is a small cyst in the eyelid. It occurs most often in the upper eyelid and is associated with Blepharitis. Chalazia start as a swollen, tender eyelid. Initially a Chalazion may cause irritation and discomfort. A Chalazion is caused by a blockage or infection in small oil producing glands in the eyelid. As the Chalazion progresses, it appears as a small unsightly lump and often feels like a tiny pea inside the eyelid. Progression may cause the eyelid to droop. Furthermore, pressure from the blockage on the cornea, can sometimes cause vision to become blurred. Chalazia can be treated at home with hot compresses. However, if this does not resolve the condition, a small operation may be required.