Effect of Suture Removal on Refraction and Graft Curvature after Deep Anterior Lamellar Keratoplasty in Patients with Keratoconus

To evaluate the effect of suture removal on refraction and keratometry measurements after deep anterior lamellar keratoplasty (DALK) performed in patients with keratoconus. This retrospective study was conducted on 54 keratoconus-affected eyes that underwent DALK. A combined suturing technique consisting of a 16-bite single running and 8-bite interrupted 10-0 nylon sutures was used at the time of keratoplasty. Selective interrupted suture removal was performed before complete suture removal in a subgroup of patients to reduce post-keratoplasty astigmatism. In another subgroup, all sutures were removed at a single session. The stitching of Running sutures did not occur in any patient. The effect of suture removal on refraction and keratometry readings was investigated in the entire study group, and the two subgroups were compared. The mean patient age was 26.6±6.7 years at the time of keratoplasty. The mean interval from surgery to complete suture removal was 17.4±5.9 months. Compared to the pre-suture removal values, there was a significant increase in the magnitudes of spherical equivalent refraction (-1.12±1.73 D; P=0.001), refractive astigmatism (-0.89±2.47 D, P=0.04), mean keratometry (1.39±1.64 D, P=0.001), and keratometric astigmatism (2.61±2.43 D, P<0.001) after complete suture removal. Subgroup analysis revealed that postkeratoplasty astigmatism could not be decreased effectively by the selective removal of interrupted sutures. Complete suture removal was followed by an unpredictable and significant increase in post-DALK refraction and keratometry readings. Corneal graft astigmatism could not be decreased significantly with selective removal of interrupted sutures when the tension of the running suture was not adjusted.