An analysis and interpretation of refractive errors after penetrating keratoplasty.

Despite advances in microsurgical techniques, astigmatism after penetrating keratoplasty is still a perplexing problem. In this paper, using retrospective studies, experiments, and observations, the factors that seem most significant in creating excessive postoperative astigmatism are delineated. The difficulty of creating a circular recipient hole of the same size and shape as the donor button appears to be a prime area for clinical research and technical development.