Effect of selective suture removal on graft astigmatism after corneal transplantation in keratoconus

Abstract

Background: Selective suture removal has been demonstrated to be effective in reducing post-keratoplasty astigmatism, while the remaining sutures are left in place. Existing studies typically focus on outcomes immediately after selective suture removal, without delving into the final suture-out keratometric astigmatism. Objectives: To examine the impact of selective suture removal on corneal graft astigmatism following keratoplasty in keratoconus and identify potential factors associated with the changes in graft astigmatism after suture removal. Design: Retrospective, comparative interventional case series. Methods: The study included 118 consecutive eyes of 118 cases that underwent corneal transplantation for keratoconus and had a keratometric astigmatism of ⩾4 D. One or two interrupted sutures corresponding to the steep meridian were removed per session. Patients were re-evaluated at 1 to 2-month intervals, repeating the procedure until achieving a keratometric astigmatism of <4.0 D or no interrupted sutures remained in the steep meridian. Results: The mean recipient age was 28.4 ± 8.4 years. A total of 234 selective suture removals were performed, with a mean of 2.0 ± 1.1 removals per eye. Pre-suture removal keratometric astigmatism significantly decreased from 6.3 ± 2.0 D to 3.91 ± 2.23 D after the completion of selective suture removal (p < 0.001). This value was significantly increased to 5.45 ± 2.93 D after all suture removal (p < 0.001). Higher pre-suture removal astigmatism and deep anterior lamellar keratoplasty were associated with a more favorable response to selective suture removal. Conclusion: Selective suture removal effectively modifies graft curvature to reduce post-keratoplasty astigmatism in keratoconus patients. However, its efficacy markedly diminishes after all sutures are removed. This procedure is particularly effective in patients with higher pre-suture removal astigmatism and those undergoing deep anterior lamellar keratoplasty.