current approaches for management of post-penetrating keratoplasty astigmatism

in addition to graft clarity, an acceptable refractive error is essential to consider a corneal transplant successful. the most common complication of penetrating keratoplasty (pk) is postkeratoplasty astigmatism which can result in decreased visual acuity, anisometropia, and mono-ocular diplopia. these complications can cause patient dissatisfaction, in spite of a successful transplant. intraoperative measures to reduce post-pk astigmatism include round and central trephination with an appropriate size, evenly distributed suture tension, and perfect apposition of recipient and donor corneas. suture manipulation in the early post operative period can effectively reduce astigmatism. if graft astigmatism is significant after complete suture removal and cannot be corrected using glasses or rigid gas-permeable contact lenses, further interventions such as relaxing incisions, compression sutures, laser refractive surgery, intrastromal corneal ring implants, wedge resection, and toric intraocular lens implantation can be considered. if these approaches fail to reduce astigmatism, then repeat pk becomes inevitable. a combination of the above mentioned approaches may be necessary to achieve an acceptable outcome.