eyelidmargin

The eyelid margin is the thin, specialized edge of each eyelid where the skin and subcutaneous tissues transition to the palpebral conjunctiva. It forms the anterior and posterior borders of the eyelid opening (the palpebral fissure) and serves as the organized interface for lashes, glands, and tear film components.

Anatomy and key features

The anterior margin lies adjacent to the skin and contains the lash line, from which eyelashes emerge. At this margin are the glands of Zeis (sebaceous) and Moll (apocrine) related to the lash follicles. The posterior margin includes the tarsal plate and the palpebral conjunctiva; Meibomian glands reside within the tarsal plate and open along the posterior edge of the lid margin onto the lid margin to contribute lipid secretions to the tear film. The mucocutaneous junction marks the transition between external skin and the conjunctival surface at the lid margin, and the medial region near the caruncle contains additional conjunctival features.

Function and significance

The margin provides a protective border for the ocular surface. Eyelashes serve as a mechanical barrier to debris, while the Meibomian glands secrete lipids that stabilize the tear film and reduce evaporation. The glands of Zeis and Moll contribute sebaceous and apocrine secretions that accompany lash follicles.

Clinical relevance

Diseases affecting the lid margin include blepharitis (anterior, involving the lash margin and its glands) and Meibomian gland dysfunction (posterior margin-related), which can lead to dry eye symptoms. Other conditions include chalazion and hordeolum, which arise from obstruction or infection of the glands along the margin. Proper assessment of lid margin health is central to diagnosing and managing lid margin pathology.