飞秒激光角膜透镜移植联合胶原交联的生物力学效应与愈合机制研究

近视手术的安全与质量的优化关系到我国4亿近视者的切身需求，实现角膜激光手术由削薄变弱的“减法”转为加固加厚的“加法”是本研究的主旨。本项目创新性地将透镜移植和角膜胶原交联技术联合，通过飞秒激光对兔及猴角膜进行三维扫描制透镜及制做基质囊袋，2mm切口取出透镜移植到受体眼并设置不同能量参数进行快速胶联。手术后用角膜地形图观察角膜屈光力及规则性，用活体共聚焦显微镜观察基质细胞反应、神经修复的规律；用透射电镜观察角膜超微结构变化；TUNEL法检测细胞凋亡、用 Real-time PCR方法从RNA水平测定角膜中TGF-β、α-SMA、IL-1、Ki-67及细胞外纤维连接蛋白mRNA含量及变化；用Corvis ST探讨角膜生物力学参数包括角膜形变时间、形变幅度、形变速率的变化规律。本项目拓展新型安全的屈光手术途径并探究其生物力学效应和愈合机制，将进一步推进近视手术，使广大近视患者受益 。

The improvements in safety and efficiency of myopic corneal refractive surgery concern vital interests of over 400 million myopic patients in China. The main purpose of this research is to convert the traditional “subtraction” principle of corneal refractive surgeries (to correct refractive errors by cutting or ablation corneal tissue) to a novel “addition” one (to correct refractive errors by thickening and strengthening corneal tissue). The project originally combines femtosecond laser assisted lenticule transplantation with accelerated corneal collagen cross-linking technique. By applying 3-dimensional scanning mode of femtosecond laser on rabbits’ or a monkeys’ corneas, a particular corneal lenticule can be extracted through a 2 millimeters-long side-cut from the corneal stromal layer of the donor and a corneal stromal pocket, which is able to contain the lenticule, can be created in the corneal stromal layer of the receptor. Accelerated corneal collagen cross-linking will be conducted soon after the extracted lenticule, which is obtained from the donor’s cornea, is transplanted into the receptor’s stromal pocket. An anterior segment analysis system (Pentacam HR, Oculus, Wetzlar, Germany) will be used to analyze the changes in refractive power and refractive uniformity of the acceptor’s cornea. Both the post-operative process of corneal nerve wound healing and the post-operative reaction of stromal cells will be assessed using an in vivo confocal microscopy. Transmission Electron Microscope will be applied to detect the changes in corneal ultrastructure. Cell death will be analyzed using TdT-mediated dUTP Nick-End Labeling (TUNEL). Various cytokines (TGF-β, α-SMA, IL-1, and Ki-67) and the changes in the expression of fibronectin mRNA were evaluated using Real-time PCR. Changes in the corneal biomechanical properties, including deformation amplitude, applanation time, applanation length, corneal velocity, peak distance, and radius will be assessed using Corvis Scheimpflug Technology (Corvis ST, OCULUS, Wetzlar, Germany). The project is designed to investigate the wound healing mechanism and changes in corneal mechanical properties following the new surgical procedure to improve the safety of refractive surgeries, which will be beneficial to the broad masses of the myopic patients.