A chalazion is a small lump in the eyelid caused by obstruction of an oil-producing or meibomian gland. Chalazia may occur in the upper or lower lids, causing redness, swelling and soreness in some cases. They may be painless if they have been present for some time. A stye or hordeolum may also occur in either lid and cause an acute painful, swollen area to the eyes. See your ophthalmologists for either of these eyelid problems.