A chalazion is a small cist on the eyelid that forms when an oil gland becomes blocked. The glands in the eyelid, called Meibomian glands, produce oil to lubricate the eyelid. When the oil hardened at the opening of the gland, the duct can become clogged. The chalazion looks like a tiny bump in the eyelid, located near the eyelashes. Very rarely, a chalazion may be caused by skin cancer, where a tiny tumor is blocking the gland. A biopsy - while often unnecessary - can rule out or confirm this diagnosis.
Chalazia may form in people who are prone to this condition due to insufficient washing of the eyelids. The first step to chalazion prevention is to clean the eyelashes daily with baby soap in order to wash away the excess oils from the Meibomian glands.
Symptoms of a chalazion, in addition to the small bump, include tender eyelids, excessive tearing, swelling accompanied by pain in the eyelid area, and light sensitivity. At times, if the chalazion grows extremely large, it can exert pressure on the cornea, leading to astigmatism. Removal of the cist reverses this condition.
Many Chalazia disappear on their own, without treatment, about a month after appearing. Treatment options do exist, however, especially for a painful or large chalazion. The most basic treatments consists of applying warm compresses for ten to fifteen minutes, four times a day. This process can soften the oils that are causing the blockage and promote drainage in the duct. Chalazia can also be treated with steroid injections. Alternatively, the chalazion can be removed surgically from underneath the eyelid.
It may be hard to differentiate between a stye and a chalazion. A stye is caused by an infection, rather than by a blockage, and it usually forms along the edge of the eyelid. A stye that forms inside of the eyelid may be confused with a chalazion, but it is called an internal hordeolum.