Endothelial cell damage due to the impingement of fragments ofcrystalline lens under cataract surgery

超声乳化是白内障手术中最常用的手术方法。在手术过程中，在将人工透镜插入眼内之前，将晶状体透镜破碎并吸出。晶状体透镜的碎片散落在后房中，可能会撞击角膜的内皮表面。这是白内障手术中内皮细胞损失的可能原因，尽管迄今为止尚未详细阐明。利用立体图像分析技术对猪眼白内障超声乳化手术中晶状体碎片的三维运动轨迹进行了测量，阐明了晶状体碎片撞击细胞的过程。碎片的轨迹显示碎片速度突然增加，并夹带到冲洗流中。碎片撞击角膜内皮表面的图像是明显的，碎片的最大速度约为100 mm/s。为了阐明碎片撞击角膜内皮细胞的影响，从猪眼提取的角膜内皮暴露于含有碎片的生理盐水射流，并通过角膜内皮显微镜观察。有碎片时细胞的最大损伤率为8%，明显大于无碎片时的损伤率，且损伤率随射流速度的增大而增大。

Phacoemulsification is most popular surgical method of cataract surgery. During operation, crystalline lens is fragmented and aspirated before insertion of the artificial lens is into intraocular. Here the fragments of crystalline lens are scattered in the posterior chamber and might impinge onto the endothelial surface of the cornea. This is a possible cause of the loss of the endothelial cell during the cataract surgery, although it was not clarified in detail so far. We measured the three-dimensional trajectory of the fragments while phacoemulsification in porcine eye by use of stereo image analysis, and clarified the process of cell damage by the impingement of the fragments. Trajectory of the fragments revealed sudden increase of the speed of the fragments which is entrained into the irrigation flow. The impingement of the fragments on the endothelial surface of the cornea was evident in the image, and the maximum speed of the fragments was about 100 mm/s.In order to clarify the influence of impingement of the fragments on the cells of corneal endothelium, corneal endothelium extracted from porcine eye was exposed to jet of physiological saline which contains the fragment, and observed by specular microscope. Maximum damage rate of the cell iwas 8% in the case with fragments, which was substantially larger than the case without fragments.Damage rate tends to become higher so that velocity of jet becomes larger.