Intraoperative evaluation of the lens during penetrating keratoplasty

The decision to extract the lens at the time of penetrating keratoplasty often depends upon the surgeon's philosophy regarding the efficacy of one-stage versus two-stage procedures, because the status of the lens in a patient with visually disabling corneal disease frequently cannot be determined before the operation. The commonly employed techniques for evaluating the clarity of the lens intraoperatively are prone to inaccuracies and often depend upon pupil size. Because a combined procedure may entail a more complicated postoperative course, some surgeons elect not to extract the lens at the time of keratoplasty. This will necessitate a second procedure which might ultimately compromise a successful corneal graft, as well as allow the possibility that some cataractous lenses may become progressively intumescent during the postoperative period and endanger the clarity of the transplant. It is, therefore, important to have a method to more accurately evaluate the status of the lens in patients with opaque corneas. The application of the coaxially-illuminated operating microscope to visualize fundus details after the corneal button has been removed permits a better estimation of the lens clarity.