To further determine whether postoperative astigmatism is related to the amount of preoperative astigmatism, we analyzed two types of against-the-rule (AR) astigmatism induced by phacoemulsification and aspiration (PEA) procedures. The operations all utilized 10-0 polyester (Mersilene) in double running fashion for the closure of the corneoscleral incisions. The induction and spontaneous regression of several types of astigmatism were analyzed over 6 months. Surgery was all done by one surgeon, with the same surgical procedure and the same number of sutures. In postoperative AR astigmatism <0.7 D at 6 months, although the amount of the astigmatism 1 week postoperatively was remarkably increased (2.66-+ 0.17D), postoperative astigmatism was decreased 6 months following surgery. On the other hand, in postoperative AR astigmatism >1.5D at 6 months, the power of the astigmatism 1 week postoperatively (2.12+0.13D) was not much higher than the preoperative level (1.38-+ 0.08D), but tended to continue increasing even 6 months after surgery. There was no difference in the power of astigmatism between 1 and 3 months postoperatively. The eyes with preoperative astigmatism (e.g. 1.38 + 0.08 D) and especially preoperative AR astigmatism (e.g. 1.60 -+ 0.11 D), showed an increase of their astigmatism after the PEA procedure. We discussed some risk factors which may induce greater postoperative AR astigmatism.