Comparison of astigmatism after penetrating keratoplasty by experienced cornea surgeons and cornea fellows

Abstract

Purpose: We compared surgically induced astigmatism after penetrating keratoplasty performed by supervised cornea fellows and experienced cornea surgeons.

Methods: Data were collected by retrospective chart review of 166 cases (166 eyes) of penetrating keratoplasty: 63 performed by two cornea surgeons and 103 by four cornea fellows. Astigmatism was calculated using scalar and vector methods. Vector analysis was performed on 109 of 166 eyes. Two techniques were compared: intraoperative keratometry and suture adjustment and the torque-antitorque running suture technique with no intraoperative keratometry or suture adjustment.

Results: Mean surgically induced scalar astigmatism changed from preoperative astigmatism by 3.27 diopters (fellows) and 2.94 diopters (attending surgeons). In 109 cases, surgically induced vector cylinder changed from peroperative astigmatism by 4.21 diopters at 98 degrees (fellows) and 4.25 diopters at 114 degrees (surgeons). Surgically induced vector astigmatism changed from preoperative astigmatism by 4.67 diopters at 93 degrees in the first 6 months (fellows) and by 3.79 diopters at 103 degrees in the second 6 months. Analysis of x-axis and y-axis components of the surgically induced vector cylinder showed that the majority of the astigmatism was induced in the y-axis and that this difference was significant (P < .001) in all comparisons, independent of technique or surgeon group.

Conclusions: Penetrating keratoplasty performed by supervised cornea fellows resulted in similar rates of surgically induced vector astigmatism, surface asymmetry, and surface regularity as that by experienced surgeons. Fellows induced significantly more with-the-rule astigmatism, but this tendency decreased with further training. Penetrating keratoplasty astigmatic outcomes were not significantly different whether or not intraopertive keratometry and suture adjustment were utilized. This study supports the concept that increased experience with corneal transplantation improves the outcome of penetrating keratoplasty by using the criterion of postoperative astigmatism as a measures.