Randomized clinical trial of penetrating keratoplasty. Before and after suture removal comparison of intraoperative and postoperative suture adjustment.

Purpose: The authors performed a prospective, randomized clinical trial of penetrating keratoplasty and compared visual acuity, refraction, and topography up to 15 months postoperatively (3 months after suture removal) after intraoperative and postoperative suture adjustment.

Methods: Twenty-five patients undergoing penetrating keratoplasty for avascular corneal pathology were randomly assigned to two groups. All surgery was done by one surgeon using the same technique (except for intraoperative suture adjustment) with suction trephination (8 mm) and a running 10-0 nylon suture. Intraoperative suture adjustment was performed in the test group and was not performed in the control group. Postoperative suture adjustment was done during the first postoperative month and up to 4 months postoperatively in all patients who had more than 3.5 diopters (D) of astigmatism. The running suture was removed at approximately 12 months postoperatively. Refraction and computed topographic analysis to compare patients with intraoperative and postoperative suture adjustment were performed at 1, 3, 6, 9, 12 (before suture removal), and 15 (after suture removal) months.

Results: There was less (P = 0.004) topographic astigmatism up to 12 months postoperatively (pre-suture removal) in patients adjusted intraoperatively (mean +/- standard deviation, 1.53 +/- 0.72 D) than in patients adjusted postoperatively (2.83 +/- 1.19 D). After suture removal, at 15 months postoperatively, astigmatism was still less in the intraoperative adjustment group (1.75 +/- 1.04 D) than in the postoperative adjustment group (2.23 +/- 17.2 D), but the authors could not demonstrate statistical significance. After intraoperative adjustment, no significant change in mean astigmatism occurred, and no patient had more than a 1.18-D change in the amount of astigmatism or more than a 22 degrees change in axis (75% < 10 degrees change) after suture removal. Corneas were more regular until suture removal in the group with intraoperative adjustment, but differences decreased after suture removal. Best spectacle-corrected visual acuity was better in the intraoperatively adjusted group until suture removal with no significant changes in best spectacle-corrected visual acuity between 1 and 15 months. Best spectacle-corrected visual acuity improved more slowly after postoperative adjustment and was different at 1 and 15 months (P = 0.0005).

Conclusion: The authors demonstrated low astigmatism and good visual results at 15 months postoperatively after either intraoperative or postoperative running suture adjustment, but intraoperative suture adjustment permitted more rapid visual rehabilitation, increased safety, and increased refractive stability.