What are meibomian glands?
Each eyelid contains several of these glands. They are modified sebaceous glands. They secrete an oily substance called meibum which coats the tear film and prevents the tears from evaporating too quickly.

What is meibomian gland disease?
The consistency of meibum varies between people, but sometimes it can become more like a thick paste than oil, causing the meibomian glands to become somewhat obstructed. They can also sequester microbes and produce ocular surface inflammation. This condition is called meibomian gland disease (MGD) and is also called posterior lid margin disease (PLMD) or posterior blepharitis. Because the meibomian secretions are abnormal, the tears can begin to evaporate too quickly. MGD can cause symptoms of burning, grittiness, dryness or irritation.

What is a chalazion?
If a meibomian gland’s duct becomes completely blocked, and the gland carries on making meibum, the gland swells up as the secretions have nowhere to go. This is called a tarsal or meibomian cyst, otherwise known as a chalazion. Some people use the lay term ‘stye’ to describe it.

Can a chalazion cause more serious problems?
Chalazia will normally go away with simple measures (see below). If they persist, the stagnant collection of meibum can become infected, causing the cyst to become hot, red, and tender. Sometimes infection can spread from the cyst to the surrounding skin of the eyelid (preseptal cellulitis) – this normally requires tablet antibiotics.

How can you get rid of a chalazion?
In many cases, melting the solidified secretions and milking them out of the gland, by warming and gently squeezing the affected area, will get the meibomian gland flowing again and some chalazia will resolve with these conservative measures. Otherwise, they can be surgically removed in a minor operation known as incision and curettage, where the cyst is incised on the inside surface of the eyelid under local anaesthesia, and its contents are removed.

Can a chalazion come back?
Yes, they can recur, either in the same location or in a different location. If a chalazion keeps coming back in the same location, it should be biopsied, because there is a small chance that it could be a rare type of cancer affecting the eyelid instead of a simple chalazion.