Phacoemulsification is most popular surgical method of cataract surgery. During operation, crystalline lens is fragmented and aspirated before insertion of the artificial lens being 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. In order to clarity the influence of impingement of the fragments on the cells of corneal endothelium, corneal endothelium exposed to jet of physiological saline which contains the fragment and calculated damage rates of the cells. Damage rate tended to become higher so that velocity of jet becomes fast. And also when the one that included the fragments did not include the fragments, damage rate was higher.