Selective positioning of the donor cornea in penetrating keratoplasty for keratoconus: postoperative astigmatism.

The final "sutures-out" astigmatism in patients who had undergone penetrating keratoplasty for keratoconus was evaluated for two groups of patients. Group 1 consisted of patients operated upon using the Troutman surgical keratometer but without giving attention to the orientation of the donor button in the recipient bed. Patients in Group 2 were also operated upon utilizing the surgical keratometer, but the donor button was rotated in the recipient bed until a position of apparent sphericity was indicated by the keratometer before suturing the graft. The mean final astigmatism was 4.42 +/- 1.85 D for Group 1 and 5.13 +/- 3.17 D for Group 2. The difference was not statistically significant. The results indicate that selective positioning of the donor button in an attempt to minimize astigmatism, as determined with a qualitative surgical keratometer, does not lead to a reduction in the final astigmatic error in patients undergoing penetrating keratoplasty for keratoconus.