Topographic changes that occur with 10-0 running suture removal following penetrating keratoplasty

Twelve eyes undergoing penetrating keratoplasty with a double-running suture technique had corneal topographical analysis immediately before and one month after 10-0 suture removal. Substantial changes in astigmatism were evident following suture removal. Twenty five percent of eyes showed a decrease of 1 D, 33% of eyes showed a decrease of 3 D, 8.3% of eyes showed an increase of 1 D, 8.3% of eyes showed an increase of 2 D, 16.6% of eyes showed an increase of 3 D, and 8.3% of eyes showed an increase of 4 D of astigmatism following suture removal. The mean corneal astigmatism did not show a significant change from a mean of 5.3 D after suture removal. There was less individual variation of spherical corneal power following suture removal. Thirty three percent of eyes showed a decrease of 1 D, 33% of eyes showed a decrease of 2 D, 8.3% of eyes showed a decrease of 3 D, 18.3% of eyes showed an increase of 1 D, and 6.6% of eyes showed an increase of 2 D of spherical power following suture removal. The surface asymmetry index (SAI), a centrally weighted measure of corneal surface irregularity, decreased significantly (P less than 0.04) from a mean of 1.17 before suture removal to a mean of 0.93 after suture removal. These results suggest that surface irregularity may be decreased following the removal of a single running 10-0 nylon suture following penetrating keratoplasty.