Chalazion 

A Chalazion is a small, usually painless, lump or swelling that appears on your eyelid. A blocked meibomian or oil gland causes this condition. It can develop on the upper or lower eyelid, and may disappear without treatment. Chalazia is the term for multiple chalazion.

A Chalazion is sometimes confused with an internal or external stye. An internal stye is an infection of a meibomian gland. An external stye is an infection in the area of the eyelash follicle and sweat gland. Styes are usually painful and chalazia usually aren’t. Chalazia may develop after styes.

Causes and risk factors

The Chalazion is caused by a blockage in one of the tiny meibomian glands of the upper and lower eyelids. The oil these glands produce helps to moisten the eyes.

Inflammation or viruses affecting the meibomian glands are the underlying causes of chalazia.

Chalazia are more common in people with inflammatory conditions like seborrhea, acne, rosacea, chronic blepharitis, or long-term inflammation of the eyelid. They’re also more common in people with viral conjunctivitis or an infection covering the inside of the eyes and eyelids.

Symptoms

A Chalazion usually appears as a painless lump or swelling on your upper or lower eyelid. Chalazia may affect both upper and lower lids and can occur in both eyes at the same time. Depending on the size and location of the chalazion, it may blur or block vision.

Although not as common, a Chalazion may be red, swollen, and painful if an infection is present