激光共焦显微镜对正常人眼角膜缘和中央角膜的观察

目的应用激光共焦显微镜对正常人眼角膜缘和中央角膜的组织结构与细胞形态的观察和分析。方法选择15名正常人的28只眼接受常规裂隙灯显微镜和检眼镜检查后,作为正常健康眼入选本研究。使用激光共焦显微镜对其上、下方角膜缘和角膜中央区进行检查,各层角膜图像均被记录,观察组织结构和细胞形态,对细胞密度进行计数并分析。结果所获角膜缘和角膜中央各层平面图像(x,y轴)及纵向断层图像(z轴)均非常清晰,同时获取动态录像。上、下方角膜缘均呈现Vogt栅栏状结构,并动态观察到血细胞在血管内的流动。表层上皮细胞排列非常疏松,边界明亮,胞体发暗,上方和下方角膜缘表层上皮细胞平均密度分别为(812±297)个/mm2和(785±263)个/mm2,二者比较差异无统计学意义(P>0.05)。上皮下可见明亮的Langerhans细胞,形态不规则,呈树枝状,上方和下方角膜缘Langerhans细胞平均密度分别为(288±102)个/mm2和(254±127)/mm2,二者比较差异无统计学意义(P>0.05)。角膜中央表层上皮细胞排列疏松,边界发亮,胞体发暗,细胞平均密度为(1098±315)个/mm2,多于上方和下方角膜缘(P<0.05)。基底上皮细胞排列紧密。上皮下和前基质层可见反光强烈的神经纤维丛,旁边偶见明亮的Langerhans细胞,形态不规则,细胞密度难以计算。浅层的神经纤维细小、弯曲度大、多小分支,深层的神经纤维粗大、弯曲度小、少见分支。基质层暗背景下散在分布细长的基质细胞,边缘欠清,细胞核明亮呈纺锤形。内皮细胞为排列整齐的六边形细胞,胞体发亮,边界发暗。角膜中央全层、基质层、上皮层厚度分别为(543.0±62.9)、(462·0±69.5)、(59.9±11.2)μm。结论激光共焦显微镜不仅可以对角膜进行无创的、实时的、活体的检查,而且与传统的光学共焦显微镜相比,具有高清晰度、确切的深度定位、时间动态观察、纵向断层扫描等优势,更可提供理想的角膜缘图像,对角膜疾病尤其是角膜缘疾病的基础研究与临床诊断将更有价值。

In vivo study of normal human limbal and central corneas using laser confocal microscope

OBJECTIVE: To observe the microstructure and cellular populations of normal human limbal and central corneas using laser confocal microscope. METHODS: The study was consisted of 28 eyes of 15 examiners (age distribution, 16-61 years). After examinations with slit lamp biomicroscopy and ophthalmoscope, the images of superior, inferior limbus and central cornea were acquired by laser confocal microscope. Corneal microstructure and cell morphology were analyzed, and cell densities were measured. RESULTS: Lateral (x, y axis) and axial (z axis) images of limbal and central cornea were clear and vivid. Limbal palisades of Vogt were visible at the superior and inferior limbus. The red blood cells in the vessel of limbus were visible. The arrangement of surface epitheliums was rather loose, with bright borders and dark cell bodies. The surface epithelial cell density was (812 +/- 297) cells/mm(2) at the superior limbus and (785 +/- 263) cells/mm(2) at the inferior limbus. There was no statistical difference between the two group (P > 0.05). The bright and dendriform Langerhans cells were readily visible just under the epithelial cells. The Langerhans cell density was (288 +/- 102) cells/mm(2) at the superior limbus and (254 +/- 127) cells/mm(2) at the inferior limbus. There was no statistical difference between the two group (P > 0.05). At central cornea, the surface epithelial cells were loose, the borders of the cell were clear and bright, and the cell bodies were dark. The cell density was (1098 +/- 315) cells/mm(2), there were more cells in central cornea than other area of superior and inferior limbus (P < 0.05). The arrangement of basal epithelial cells was tight. Nerve plexus at subepithelium and anterior stroma were prominent with strong brightness. Langerhans cells were occasionally visible, and cell density cannot be measured. Subepithelial nerve fibers were thin with high tortuosity and a lot of branches, and deeper ones were thick with low tortuosity and few branch. In the stroma, separated keratocytes were visible under dark background, the boundaries were vague, the nucleis were bright and spindly. Hexagonal endothelial cells were arranged in order with light cell bodies and dark borders. The thickness of whole cornea, stroma or epithelium was (543.0 +/- 62.9), (462.0 +/- 69.5), (59.9 +/- 11.2) microm respectively. CONCLUSIONS: Laser confocal microscopy provides non-invasive, real-time, in vivo images of limbal and central corneas characterized with refined image definition, exact depth localization. It is valuable for basic research and clinical diagnosis of corneal disease.