Study of precorneal tear film thickness and structure by interferometry and confocal microscopy.
Study of precorneal tear film thickness and structure by interferometry and confocal microscopy.
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发表时间：
1992-05
影响因子：
4.4
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过去对兔子和人类角膜前泪膜厚度的测量结果为 4-7 微米。这些都是公认的价值观。然而，本报告中提供的测量结果要高得多。早期的技术可能改变了膜的厚度或者没有完全包括含有粘液的层。人们对粘液成分知之甚少。使用两种独立的光学技术测量了 10 种新鲜杀死的动物的厚度。相干光从眼睛反射，厚度由干涉条纹的间距确定。通过共聚焦显微镜获得组织结构的清晰图像，目视识别泪膜并测量厚度。两种方法的测量结果在每只动物中密切相关。在鳟鱼或鲤鱼中未检测到薄膜。在其他物种中，厚度范围从青蛙的 9 微米到沙鼠的 15 微米。数值明显大于之前的估计。三只活兔子的膜厚度与死后不久测量的膜厚度没有显着差异。三个物种的角膜五个位置的厚度没有变化。通过测量施用 4%、8% 和 20%（重量/体积）乙酰半胱氨酸（一种粘液溶解剂）后的变薄情况来检查大鼠泪膜的粘液含量。与对照相比，厚度显着减小，并且在最高浓度下膜几乎完全去除。作者提出，这层薄膜主要由粘液组成，而不是游离的水溶液。我们的方法包括这样的层，并且测量结果相应地比早期的方法更大。
Past measurements of precorneal tear film thickness in rabbits and humans gave values of 4-7 microns. These have been the accepted values. However, measurements presented in this report are much higher. Earlier techniques may have changed film thickness or not have fully included the layer containing mucus. Little is known about the mucus component. Thickness was measured in freshly killed animals of 10 species using two independent optical techniques. Coherent light was reflected from eyes and thickness was determined from spacing of interference fringes. Clear images of tissue structure were obtained with confocal microscopy, the tear film was visually identified, and thickness measured. Measurements by the two methods were closely correlated in each animal. No film was detected in trout or carp. In other species, thickness ranged from 9 microns in frogs to 15 microns in gerbils. Values are significantly larger than earlier estimates. Film thickness in three living rabbits was not significantly different from that measured shortly after death. There was no variation in thickness at five positions across the cornea in three species. Mucus content of rat tear film was examined by measuring thinning after application of 4, 8, and 20% (weight/volume) acetylcysteine, a mucolytic agent. Thickness was considerably reduced compared to controls, and the film almost completely removed by the highest concentration. The authors propose that the film is largely composed of mucus, not free aqueous solution. Our methods include such layers, and measurements are correspondingly larger than earlier ones.