Located in the thickness of the tarsus of the eyelids, the meibomian glands are sebaceous glands which secrete the lipid surface layer of the tear film, called meibum.
Discovered by the German doctor Heinrich Meibom from whom they take their name, these glands allow lubrication of the cornea by mixing with tears. Meibomian gland dysfunction is characterized by a change in appearance of meibomian secretions and obstruction of the gland openings. Infection of these glands is called chalazion.