P 114Effects of the knot positions on the local dioptric power with sequential removal of a double running suture after penetrating keratoplasty
A. Langenbucher, B. Seitz, G. O. H. Naumann
To determine the effects of the knot position on the local dioptric power with sequential removal of a double running suture after nonmechanical and mechanical penetrating keratoplasty.
Patients and Methods: 179 patients (104 with keratoconus, 75 with Fuchs dystrophy, 84 after nonmechanical (NMT) and 87 after mechanical trephination (MT), double-running cross-stitch suture, opposite knots (5-7 h)) were examined with corneal topography analysis (TMS-1, Tomey). Dioptric power and axis were evaluated in the four hemimeridians of the 3-mm zone before removal of the first suture (FSR) and before/after removal of the second suture (SSR). With a quadratic interpolation scheme the dioptric powers 1) at both knots, 2) on the opposite side and 3) orthogonally were calculated.
Results: FSR/SSR was 13±4/20±3 months after keratoplasty. Before FSR the dioptric power after NMT/MT at the knot to be removed first was 43.04/43.84 D, at the opposite side it was 43.61/43.92 D and orthogonally it was 42.28/43.67 D. Before SSR the dioptric power after NMT/MT at the knot to be removed first was 44.24/44.84D(p=0.02/p=0.05) at the opposite side it was 44.39/44.48 D and orthogonally it was 43.53/43.59 D. Before SSR the dioptric power after NMT/MTat the knot to be removed last was 44.39/44.63 D, at the opposite side it was 44.23/44.92 D and orthogonally it was 43.50/43.90 D. After SSR the dioptric power after NMT/MT at the knot to be removed last was 44.35/43.94 D, at the opposite side it was 44.43/44.18 D and orthogonally it was 43.50/44.11 D. Between groups of patients and locations there was no statistically significant difference at any examination time (p³ 0.08). With keratoconus all local powers changed significantly more (p£ 0.01) after SSR than with Fuchs dystrophy.
Conclusions: The knot position seems to have no significant effect on the local dioptric corneal power distribution after sequential suture removal of a double running cross-stitch suture following penetrating keratoplasty. Change of local powers after removal of the second suture was significantly higher with keratoconus.
Department of Ophthalmology, University of Erlangen-Nürnberg, Schwabachanlage 6, D-91054 Erlangen, Germany