The lipid layer of tears: dependent on meibomian gland function

There is growing laboratory and clinical evidence implicating the meibomian glands of the eyelid as playing a critical role in the pathogenesis of various ocular surface disorders Such as chronic blepharitis and dry eye. Meibomian glands produce a lipid material whose synthesis is dependent on factors such as stem cells, neurological stimulants and hormones. This lipid material is fluid, spreads easily, is a surfactant as well as an aqueous barrier, and must remain functional after a blink. Before delivery it can be modified by factors Such as hormone abnormalities and even after delivery it may be modified by lipases produced by ocular bacteria. (C) 2003 Elsevier Ltd. All rights reserved.