Changes in refraction and corneal topography induced by suture removal following penetrating keratoplasty

Changes in refraction and corneal topography induced by removal of running sutures following penetrating keratoplasty were studied prospectively in 37 eyes of 35 patients. The mean age of patients who had suture-related foreign body reactions was younger than that of patients who did not have such reactions (p=0.0008). Herpes keratitis and corneal ulcer were the leading indications for keratoplasty in patients with foreign body reactions, whereas corneal scarring was the most frequent indication in patients without such reactions. Mean refractive astigmatism was 5.14±2.60 diopters before suture removal and 4.66±2.32 diopters after suture removal (p=0.58). Mean simulated keratometry values, calculated from the results of corneal topography, were 8.01±4.94 diopters before suture removal and 6.07±2.54 diopters after suture removal (p=0.18). Although these changes were not statistically significant, all eyes with more than 6 diopters of refractive astigmatism or simulated keratometry values of more than 9 diopters before suture removal had less astigmatism after suture removal. A significant decrease in the surface regularity index was noted after suture removal (2.92±2.12 to 2.02±1.48, p=0.045). Although the surface asymmetry index also decreased after suture removal (1.68±1.21 to 1.11±0.48), the change was not statistically significant (p=0.10). In conclusion, sutures should be removed after penetrating keratoplasty in eyes having high degrees of astigmatism. The procedure is beneficial not only for reducing astigmatism but also for normalizing corneal topography.