干眼症的发病机制

Dry eye and its pathogenesis

眼表(角膜、结膜、副泪腺和睑板腺)、主泪腺和它们之间的神经连接组成的泪腺功能单位共同发挥对泪液分泌和泪膜形成的调控作用,维护眼表的健康,其中任一环节的损害均可导致泪膜完整性和正常功能的破坏。引起干眼症的起始病因很多,如果这些因素在未引起眼表改变时消失,则泪膜恢复正常;如这些因素不能消失,则引起眼表面的病理改变。虽然干眼症的临床表现类型不同,但其病理生理改变是相似的,炎症是干眼症发病机制中最关键的病理生理改变,而细胞凋亡、神经调节及性激素等也共同参与了干眼症的发病过程。

Tear secretion is controlled by the lacrimal functional unit consisting of the ocular surface（cornea, conjunctiva, accessory lacrimal glands, and meibomian glands）, the main lacrimal gland and the interconnecting innervation. Abnormalities at any portion of this functional unit can result in a loss of tear film integrity and normal function. Many factors contribute to dry eye. The tear film will recover if the causes are eliminated before pathophysiological changes happen on the ocular surface. However, the ocular surface will be damaged by unstable tear film. Whatever the initial causes of dry eye, the diseases show the similar pathophysiological process in the progressing phase. Inflammation is the key mechanism and the other factors such as apoptosis, nervous and hormonal regulation are closely involved in dry eye pathngenesis.