高重复频率纳焦单脉冲能量飞秒激光巩膜蚀除的基础研究

发布时间：2018-05-19 13:45

本文选题：飞秒激光 + 微加工　；参考：《华中科技大学》2016年博士论文

【摘要】：目的：本研究致力于评估高重复频率纳焦单脉冲能量飞秒激光(纳焦飞秒激光)在抗青光眼手术巩膜组织高精度加工中的应用。衡量纳焦飞秒激光是否能对巩膜进行切割及探索纳焦飞秒激光对巩膜的生物及物理改变。背景：青光眼是世界范围不可逆性致盲的首要病因。常规抗青光眼手术远期效果不佳,手术切口纤维化是导致手术失败主要原因。手术过程中对组织的微创操作有利于减少术后纤维化的形成。纳焦飞秒激光组织切割因其切割精细,对周围组织损伤极小且形成切口内壁光滑等特征,为预防抗青光眼术后纤维化提供了新契机。方法：用纳焦飞秒激光对兔离体巩膜进行蚀除,计算机控制的三维平台用于实现各种形式的扫描。扫描过程中组织表面实时观察由电荷耦合装置(cCD)完成,组织表面温度分布由红外热像仪完成,组织样本的形态学改变由扫描电镜观察(SEM),组织样本热效应由组织切片HE染色及Masson染色观察。结果：纳焦飞秒激光作用于离体兔巩膜可形成裂隙样,矩形,表面下蚀除。单次线性扫描显示,切口深度与曝光时间成正比,与聚焦深度成反比。激光对组织加工过程中,实时观测可得：纳焦飞秒激光对组织加工时可产生热累积效应,且与单脉冲能量及曝光时间成正比。通过对切口横截面扫描电镜观察得出,激光切口内壁非常光滑(Ra=0.93±0.14μm)。通过HE及Masson染色观察显示：激光加工时组织可出现颜色加深,胶原蛋白皱缩等变化。比较纳焦飞秒激光与低重复频率微焦单脉冲能量飞秒激光(微焦激光)巩膜组织蚀除结果示：微焦激光光栅扫描所得切口内表面粗糙度明显大于纳焦飞秒激光所得切口内表面粗糙度,差别具有统计学意义(P=0.0135)。结论：该研究阐述了纳焦飞秒激光在抗青光眼手术微创激光巩膜蚀除中的潜在应用价值。据笔者所知,此乃纳焦飞秒激光对抗青光眼手术巩膜切除的世界范围内首次研究。应用1040nm波长飞秒激光实现了水和巩膜表面下蚀除。且通过组织热损伤研究证明了纳焦飞秒激光对组织加工热效应较小。与微焦激光相比,纳焦飞秒激光可加工形成极精细且光滑的巩膜切口,有望应用于抗青光眼滤过手术中。
[Abstract]:Objective: to evaluate the application of high repetition rate nanfocal single pulse femtosecond laser (NRF) in high-precision scleral tissue processing in glaucoma surgery. To evaluate whether nanoclock femtosecond laser can cut sclera and explore the biological and physical changes of nanoclock femtosecond laser on sclera. Background: glaucoma is the leading cause of irreversible blindness worldwide. The long-term effect of conventional anti-glaucoma surgery is not good. The main cause of surgical failure is surgical incision fibrosis. The minimally invasive operation of tissue during operation is helpful to reduce the formation of postoperative fibrosis. Nano-Femtosecond laser tissue cutting provides a new opportunity for preventing fibrosis after glaucoma surgery because of its fine cutting, minimal injury to surrounding tissues and smooth inner wall of incision. Methods: the rabbit sclera was etched by nanoco femtosecond laser. The three dimensional platform controlled by computer was used to realize scanning in various forms. The real-time observation of the tissue surface was accomplished by the charge coupled device (CDD), and the temperature distribution of the tissue surface was accomplished by the infrared thermal imager. The morphological changes of tissue samples were observed by scanning electron microscope (SEM), and the thermal effects of tissue samples were observed by HE staining and Masson staining. Results: Femtosecond laser could form fissure shape, rectangle and surface erosion in isolated rabbit sclera. Single linear scanning shows that the incision depth is directly proportional to the exposure time and inversely proportional to the focus depth. In the process of laser processing, it can be found that the femtosecond laser can produce thermal accumulative effect, which is proportional to the single pulse energy and exposure time. The results of scanning electron microscopy show that the inner wall of the laser incision is very smooth, which is 0.93 卤0.14 渭 m 路m ~ (-1). The results of HE and Masson staining showed that the changes of color and collagen shrinkage were observed during laser processing. Comparing the results of scleral tissue erosion between nanfocal femtosecond laser and low-repetition frequency microfocal single-pulse femtosecond laser (micro-focal laser), the results show that the internal surface roughness of microfocal laser raster scanning is obviously greater than that of nanfocal femtosecond laser. The roughness of the inner surface of the notch, The difference was statistically significant (P = 0.0135). Conclusion: this study describes the potential application value of nanokinetic femtosecond laser in minimally invasive laser scleral ablation in anti-glaucoma surgery. To the best of my knowledge, this is the first worldwide study of nanokorph femtosecond laser antiglaucoma surgery sclera resection. Water and scleral surface etching was realized by 1040nm femtosecond laser. The results of tissue thermal damage show that the femtosecond laser has less thermal effect on tissue processing. Compared with microfocal laser, nanoco femtosecond laser can produce extremely fine and smooth scleral incision, which is expected to be used in glaucoma filtering surgery.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R779.6

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