Lemp M A
Center for Sight, Georgetown University Medical Center, Washington, D.C. 20007.
Cornea. 1990;9 Suppl 1:S48-50; discussion S54. doi: 10.1097/00003226-199010001-00020.
Numerous studies have demonstrated that patients with dry eyes have a compromised ocular surface. Furthermore, these patients suffer deficiencies of various surface defense mechanisms, such as tear volume, tear components (lysozyme, lactoferrin, and beta-lysin), the mucin network, cellular exfoliation, and subsurface immune secretions. When such individuals wear contact lenses (CLs), a special set of circumstances arises that increases the risk of ocular infection. The risk is greatest if the lenses are soft and, therefore, provide for little tear exchange beneath their surface. Under such circumstances, limited tear flow allows for a greater buildup of lens deposits and metabolic wastes, while permitting increased tear evaporation from the lens surface. The pathogenesis of infection is attributed to various mechanisms, including decreased tear flow beneath the lens, decreased tear components, stagnation of the mucin network, changes in surface cell exfoliation, and putative changes in the subsurface immune secretory system. Dry eye patients who wear soft CLs also run a greater risk of bacterial conjunctivitis, blepharitis, and sterile corneal infiltrates.
大量研究表明，干眼症患者的眼表功能受损。此外，这些患者还存在各种表面防御机制的缺陷，如泪液量、泪液成分（溶菌酶、乳铁蛋白和β-溶素）、黏蛋白网络、细胞脱落以及眼表免疫分泌物。当这些人佩戴隐形眼镜时，会出现一系列特殊情况，增加眼部感染的风险。如果镜片是软性的，风险会最大，因为软性镜片在其表面下方几乎没有泪液交换。在这种情况下，有限的泪液流动会使镜片沉积物和代谢废物大量堆积，同时使泪液从镜片表面的蒸发增加。感染的发病机制归因于多种机制，包括镜片下方泪液流动减少、泪液成分减少、黏蛋白网络停滞、表面细胞脱落变化以及眼表免疫分泌系统的假定变化。佩戴软性隐形眼镜的干眼症患者还面临更高的细菌性结膜炎、睑缘炎和无菌性角膜浸润风险。
