Adjustment of Running Suture to Control Postkeratoplasty Astigmatism

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

PURPOSE

To evaluate the effect of suture removal on refraction and keratometry measurements after deep anterior lamellar keratoplasty (DALK).

METHODS

This retrospective study enrolled 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 in a subgroup of patients to reduce postkeratoplasty astigmatism. In another subgroup, all sutures were removed at a single session. Adjustment of the running suture tension was not performed in any case. The effect of suture removal on refractive outcomes was investigated in the entire study group, and the 2 subgroups were compared.

RESULTS

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 with the pre-suture removal values, there was a significant increase in the magnitude of myopia (-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 selective removal of interrupted sutures was effective as long as remaining interrupted and running sutures were left in place.

CONCLUSIONS

Complete suture removal was followed by an unpredictable and significant increase in post-DALK refraction and keratometry readings. In the subgroup that underwent early selective removal of interrupted sutures before complete suture removal, the desirable effects of this procedure significantly diminished after all remaining sutures were completely removed.

Sequential selective same-day suture removal in the management of post-keratoplasty astigmatism

AIMS

In a previous study, we proposed that corneal topography performed 30-40 min after the initial suture removal can identify the next set of sutures requiring removal, for the treatment of post-keratoplasty astigmatism. The aim of this study was to evaluate the effect of removing subsequent sets of sutures at the same sitting.

METHODS

10/0 nylon interrupted sutures were placed, to secure the graft-host junction, at the time of keratoplasty. Topography was performed using Pentacam (Oculus) before suture removal. The sutures to be removed in the steep semi-meridians were identified and removed at the slit-lamp biomicroscope. Topography was repeated 30-40 min post suture removal, the new steep semi-meridians determined, and the next set of sutures to be removed were identified and removed accordingly. Topography was repeated 4-6 weeks later and the magnitude of topographic astigmatism was recorded. A paired-samples t-test was used to evaluate the impact of selective suture removal on reducing the magnitude of topographic and refractive astigmatism.

RESULTS

Twenty eyes of 20 patients underwent sequential selective same-day suture removal (SSSS) after corneal transplantation. This study showed that the topographic astigmatism decreased by about 46.7% (3.68 D) and the refractive astigmatism decreased by about 37.7% (2.61 D) following SSSS. Vector calculations also show a significant reduction of both topographic and refractive astigmatism (P<0.001).

CONCLUSION

SSSS may help patients to achieve satisfactory vision more quickly and reduce the number of follow-up visits required post keratoplasty.