飞秒激光对活体人眼角膜组织瞬间作用后超微结构变化的研究

The study of the changes of ultra-microstructure after a momentary action of femtosecond laser with human corneal tissue in vivo

目的：探索飞秒激光光裂解作用对活体人眼角膜组织的早期损伤情况。方法采用Visu Max飞秒激光系统对25只近视眼进行小切口基质内透镜取出术，分别对取出的角膜透镜组织进行光学显微镜、扫描电镜和透射电镜的观察。结果在光学显微镜下，角膜透镜组织中部分胶原纤维有轻度水肿；边缘可见一薄层组织深染，成线状排列；中央区透镜组织浅层可见到少量气泡。在扫描电镜下，透镜的前表面较为光滑，未见明显的组织桥，透镜后表面较前表面略显不规则，可见散在组织桥及之间飞秒激光光爆破作用后残留的痕迹。在透射电镜下，角膜透镜基质中相邻胶原纤维板层相互交叉规则排列，未见明显的胶原纤维的断裂和板层的分离。角膜透镜一侧切割缘胶原纤维断口呈线状。角膜透镜中心部位的角膜基质细胞损伤较轻。而距离透镜边缘较近的角膜基质细胞破坏较为明显，部分角膜细胞被固化，并且断裂成若干碎块。被破坏的角膜基质细胞有的仅留有残骸，部分角膜细胞所占据的空间成为裂隙。结论飞秒激光与人眼角膜组织相互作用后的早期未发现明显的损伤作用，激光聚焦区边缘的组织有轻度热损伤和细胞结构的改变，而非聚焦区域的组织结构未见异常表现。（中华眼科杂志，2015，51：520-526）

Objective To observe the changes of pathology and ultra-microstructure of corneal lenticules extracted by femtosecond laser small incision lenticule extraction surgery and to investigate instantaneous damage of photodisruption of femtosecond laser to human corneal tissue in vivo. Methods The small incision lenticule extraction surgeries in 25 myopic eyes were performed with Carl Zeiss VisuMax femtosecond laser, and the lenticules were observed by light microscopy, scanning electron microscopy and transmission electron microscopy. Results Light microscopy showed slight edema in part of the collagen fibers in the cornea lenticule tissue. A thin layer of deep tissue dyeing at the edge of the lenticule was observed on a linear array. In the center of superficial lenticule tissue existed a few bubbles. Under the scanning electron microscope, the anterior surface of the lenticule was found to be relatively smooth, with no obvious tissue bridge. The posterior surface of the lenticule was slightly irregular compared with the anterior surface. Scattered tissue bridges and residual traces of the effect of femtosecond laser photodisruption could be observed. Under the transmission electron microscope, adjacent collagen fiber layers in the corneal lenticule matrix were detected to cross each other regularly, with no breakage of the collagen fibers or separation of the layers. The incision of the collagen fibers on one side of the lenticule was on a linear alinement. It can also be observed that the central part of the lenticule was mildly damaged. However, the stroma cells near the lenticule limbus were severely damaged. Part of the corneal stroma cells were solidified with several shivers, which might be due to the photodisruption. Some of the damaged corneal stroma cells＆nbsp;were observed with remnants, while the spaces occupied by part of the corneal cells became fractured. Conclusions Obvious damage of the femtosecond laser to the corneal tissue at early stage was not observed. At the edge of the area where femtosecond laser focused, there were mild thermal injury and slight structure change. There were not abnormal appearances of the tissue structure at the non-focus area.