There is increasing interest in the surgical correction of refractive errors. Candidates include aphakes, both adult and pediatric (who might otherwise develop amblyopia), who have failed with contact lenses, patients with high astigmatism and myopes who have subnormal vision with their spectacles or who desire good unaided acuity. The surgical techniques of lamellar refractive keratoplasty (keratophakia, keratomileusis and epikeratophakia) have provided barely acceptable results until now. It is the concensus of experienced refractive surgeons that the steps of freezing and lyophilization, which inflict severe damage upon all layers of the cornea, are the major drawback with this surgery. The principal investigator has developed a new technique and keratome capable of preparing lamellar refractive lenticules for the above procedures without the need for freezing or lyophilization. Preliminary laboratory and clinical evaluation has demonstrated its potential. In addition, the PI has developed a corneal press to return edematous corneas to normal dimensions. This proposal outlines laboratory and controlled animal studies that must be performed before the new keratome is used in widespread clinical studies. The studies include: 1) a thorough evaluation of the keratome's accuracy and the quality of the optical cuts produced, 2) an evaluation of the postoperative clinical course of myopic epikeratophakia and keratomileusis, and keratophakia, when performed with viable tissue, 3) a histologic and ultrastructural evaluation of all layers of the postoperative cornea for these three procedures, using appropriate animal models, 4) an evaluation of the ultrastructural effects of the corneal press on the cornea, and 5) the development of an appropriate storage media or device for maintaining the viability and architecture of the stroma of viable refractive lenticules, thereby allowing their use in a precarved fashion for distribution to surgeons by eye-banks.
