Simultaneous and sequential selective suture removal to reduce astigmatism after penetrating keratoplasty

We studied two separate groups of consecutive eyes with penetrating keratoplasty in avascular corneas in which we performed selective interrupted suture removal to decrease postoperative astigmatism, describing the time course of change in astigmatism. In the first group (29 eyes), multiple interrupted sutures were selectively removed at a single visit in an attempt to reduce the astigmatism to less than or equal to 3 diopters; the patients were followed for 30 months. In the second group (24 eyes), one interrupted suture was removed at each visit every 2 weeks until the astigmatism was less than or equal to 3 D; the patients were followed for 15 months. Surgical techniques were different in the two groups. Both techniques reduced postoperative astigmatism. Larger changes in astigmatism occurred between the first suture removal visit and the subsequent visit in the first group. At 1 year, the multiple-suture-removal-at-a-single-visit group averaged 3.1 D of astigmatism, with 50% of eyes less than or equal to 3 D, whereas the single-suture-removal-at-multiple-visits group had a mean astigmatism of 1.9 D with 88% of eyes less than or equal to 3 D. The two groups we studied were not directly comparable, because surgical techniques differed, because they were operated at different times, and because the cases were not randomized. Nevertheless, we think that selective suture removal to reduce astigmatism after penetrating keratoplasty is best done by removing only one (or sometimes two) sutures per examination.