In a prospective study, two groups of 35 patients each were compared following phacoemulsification and posterior lens implantation. Both groups were followed up to evaluate the evolution of the postoperative astigmatism during a minimum of 6 months. In group A, a HEMA posterior chamber lens was implanted through a 3.5 mm scleral tunnel incision. In group B, a PMMA posterior chamber lens was implanted through a 7 mm scleral step incision. The data were analyzed for the whole observation time with reference to preoperative, early postoperative, absolute and induced astigmatism. Different subgroups were formed. Vector analysis was performed in both groups in order to determine surgically induced axial changes, e.g., the intensity and direction of the power working on the cornea. The results were compared. Group A showed lesser early postoperative astigmatism than group B; however, group A also returned to the preoperative values more quickly. Both groups exhibited a shift towards against-the-rule astigmatism.