The eyelid margin: an underestimated contributor to ocular surface health and disease

Abstract

Abstract Purpose The eyelid margin is frequently underestimated in the consideration of factors in ocular surface health and disease. Clinically the whole free end of the lid margin is often addressed simply as “margin” without further differentiation. It is attempted to review the structure, embryology and function of the lid margin as well as its involvement in ocular surface pathology. Methods A review based on the available literature on the lid margin is prepared together with own findings on the histology of normal and pathological tissues. Results The human lid margin is divided into distinct zones that consist, coming from the skin side, of a rounded outer lid border, a free lid margin (between the eye lashes and the opening of the meibomian glands), the muco‐cutaneous junction and a sharp inner lid border. The embryological development of the eye lids and their tissue components (loose connective tissue, lid muscles, ciliary hairs, Meibomian glands and vascular and neural components) takes place during the period of sealed lids. During this time the development of the Meibomian glands shows considerable similarity to that of the ciliary hairs. The sealing of the mesodermal lid folds and their eventual separation is dependent on several factors that may be involved in pathology. Various disease states, as well as the aging process, can lead to destruction of the lid margin and, conversely, this can lead to deterioration of the cornea and conjunctiva. Conclusion The eyelid margin is an underestimated contributor to ocular surface health and disease. Increased awareness of the anatomy, embryology, physiology and pathophysiology of the lid margin and it tissue components appears important for the preservation of ocular surface integrity. Support DFG KN317/11