Corneal dynamics after single interrupted suture removal following penetrating keratoplasty.

PURPOSE: To evaluate corneal topographic changes after removal of a single interrupted suture in patients who underwent keratoplasty for keratoconus.

METHODS

Fifteen interrupted sutures in 15 eyes after keratoplasty were removed to control astigmatism in a prospective clinical study. Videokeratography using an EyeSys Corneal Analysis System was performed before suture removal, and 1 hour, 1 day, 1 week, and 2 to 4 weeks after suture removal. Changes in dioptric power and axis of the steepest and flattest semimeridians were evaluated.

RESULTS

The range of the dioptric change of the steepest semimeridian was from -0.43+/-0.34 D during the first hour to +0.70+/-0.39 D from 1 day to 1 week. The largest axis change of the steepest semimeridian (17.1 degrees+/-5.6 degrees, range 1 degree to 66 degrees ) occurred during the first hour (P = .006). The largest surgically induced vectorial change occurred during the first hour (16.10 @ 10.5 ), while relative stability of the steepest semimeridian was observed during the rest of the study period. Changes in power and axis of the flattest semimeridian were also demonstrated. A variety of topographic corneal patterns were demonstrated following suture removal, indicating unpredictable change of astigmatism.

CONCLUSIONS

The steepest semimeridian of the central 3-mm zone showed maximal vectorial change 1 hour following suture removal. Reciprocal changes occurred at the same time in the flattest semimeridian. The response of the corneal surface to suture removal is unpredictable and complex.