Tarsus (eyelids) is a groove in the inner surface of each eyelid. Along the inner margin of the tarsus are modified sebaceous glands known as tarsal glands (or meibomian glands), aligned vertically within the tarsi: 30 to 40 glands in the upper lid, and 20 to 30 in the lower lid, which secrete a lipid-rich product which helps keep the lacrimal secretions or tears from evaporating too quickly, thus keeping the eye moist. Tarsus (eyelids) The tarsi (tarsal plates) are two comparatively thick, elongated plates of dense connective tissue, about in length; one is found in each eyelid, and contributes to its
Meibomian gland lipidomic analysis of meibum is mass spectrometry either with direct infusion or in combination with liquid chromatography. In humans, more than 90 different proteins have been identified in meibomian gland secretions. Dysfunctional meibomian glands often cause dry eyes, one of the more common eye conditions. They may also contribute to blepharitis. Inflammation of the meibomian glands (also known as "meibomitis", "meibomian gland dysfunction", or "posterior blepharitis") causes the glands to be obstructed by thick waxy secretions. Besides leading to dry eyes, the obstructions can be degraded by bacterial lipases, resulting in the formation of free fatty acids, which irritate the