Cataract Following Keratoplasty
Cataract formation soon after keratoplasty may be caused by lens trauma during the transplantation procedure or by prolonged corticosteroid use to prevent graft rejection. It is preferable to delay cataract surgery in an eye with a history of PKP until the corneal contour and surface are stable and reliable keratometry readings are obtained. The probability of graft survival 5 years after cataract surgery is at least 80%; nevertheless, a corneal graft may not survive even routine cataract surgery.
Preoperatively, the surgeon evaluates the corneal graft for thickening and anticipated reduced intraoperative clarity through the graft. A scleral tunnel approach has the benefits of being farther from the corneal transplant and minimizing endothelial trauma during surgery. The risk of postoperative graft failure is lowest when the corneal endothelium is protected with a dispersive OVD during surgery and when postoperative inflammation is aggressively treated.
Selecting the IOL power before the cornea is fully healed can lead to implantation of an incorrectly powered IOL and symptomatic anisometropia. Posterior chamber lenses are preferred because they minimize contact between the optic and the corneal endothelium. If capsular support is inadequate for IOL placement in the capsular bag (ie, “in-the-bag”), a posterior chamber scleral fixation or iris suture may be placed. If the additional manipulation required for a sutured lens poses a risk of excessive endothelial trauma, insertion of a flexible anterior chamber IOL (ACIOL) is an option. A modified IOL target may be considered in patients who have had previous corneal transplantation and are undergoing cataract surgery. The goal of this is to balance the 2 eyes.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.