What causes a chalazion?

A chalazion or meibomian cyst is a type of swelling that affects the eyelid. As with anything that affects the eye, such a swelling can be worrying, especially if it hardens. What causes a chalazion and why do they harden? Expert ophthalmologist Miss Vickie Lee explains.

How does a chalazion form?

A chalazion, also known as a meibomian cyst, is the most common cause of a localised eyelid swelling. This is caused by blockage of the meibomian oil glands that produce the oily component of the tear film. There are approximately 20 to 30 meibomian glands on the lower lid and 40 to 50 on the upper lid. The gland openings are in the margin of the eyelid in contact with the ocular surface. Cosmetically, a chalazion can be unsightly; if large enough they can obstruct vision and occasionally can lead to ocular surface and eyelid inflammation or infections. In some conditions, such as meibomian gland dysfunction and rosacea, many glands can become blocked frequently.

Will a chalazion go away on its own?

Patients are usually initially advised to apply hot compresses to the chalazion to liquefy the secretions in the blocked gland and to massage the eyelid to encourage the blocked gland to spontaneously drain. If this is done in the early stage, one study has found there is about a 50/50 chance of resolving the chalazion.

Why do chalazions harden?

If the gland becomes permanently blocked, the secretions can harden into a noticeable lump. This is not dangerous, but is often irritating. The options at this stage are to leave it alone and hope that the chalazion will slowly settle with time or treat it with a minor operation called incision and curettage (I&C) under a local anaesthetic injection. A localised steroid injection can also be used in some cases to resolve the chalazion instead of surgery. There is a high chance of resolving the chalazion with either procedure.

Your ophthalmologist can advise you which option best suits the type of chalazion. It is important that the chalazion is diagnosed correctly and other causes of eyelid swelling are excluded.

How do you prevent chalazion?

Regular lid massage after applying heat may help to keep the glands in good functioning order. There is evidence that dietary supplementation with omega-3 fatty acids may help prevent chalazion. Meibomian gland dysfunction can sometimes be associated with a low grade mite infection so a course of low dose antibiotics may help in patients with recurrent and multiple chalazia.

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