Long-term evolution of astigmatism following planned extracapsular cataract extraction.

Sixty-six eyes of 66 patients undergoing planned extracapsular cataract extraction with interrupted 10-0 nylon suture wound closure were followed up prospectively for three years following surgery to evaluate the long-term evolution of postoperative astigmatism. The study examined the period beginning three months postoperatively, well after all suture cutting was completed, a point often considered to represent "final postoperative astigmatism." For the group as a whole, the induced astigmatism measured at three months was not stable, but gradually shifted 0.69 diopter toward against-the-rule astigmatism. Three specific patterns of evolution of postoperative astigmatism were identified, depending on the amount of induced astigmatism found at three months. The data revealed that it was not possible to consistently induce with-the-rule astigmatism, although permanent against-the-rule induced astigmatism could be produced. The long-term evolution of postoperative cataract wounds toward more against-the-rule astigmatism seen in this study was not affected by the number of intact nylon sutures. Proper evaluation of any technique to modify postoperative astigmatism must consider the long-term evolution of the cataract wound.