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entire cornea, DALK replaces only the diseased portion. Like DSEK, DALK involves the injection of air, in this case to separate the corneal stroma from the underlying Descemet’s membrane and endothelial cells. By enabling the surgeon to preserve the inner layer of the cornea, DALK has several advantages over penetrating keratoplasty, explains Dr. Aldave. Because the inner layer of the cornea remains intact, the eye is not entered, and thus there is no risk of damaging the intraocular tissue such as the lens and the iris, and there is less chance of intraocular infection. In addition, because the healthy endothelial cells are not replaced, there is no risk of rejection and failure of the endothelial cells that are critical to keeping the cornea clear. Moreover, the requirements of the donor tissue are much less stringent than with the penetrating keratoplasty. Penetrating and Deep Anterior Lamellar Keratoplasty with a Femtosecond Laser The third, and newest, approach to corneal transplantation at UCLA is lamellar and penetrating keratoplasty with a femtosecond laser. The laser replaces the trephine by using ultra-fast energy pulses to make incisions in the cornea. This enables the surgeon to create precisely shaped incisions so that the transplanted tissue fits into the cornea like an interlocking puzzle piece, resulting in faster visual rehabilitation and less astigmatism. The procedure is most appropriate for patients who have not had a prior corneal transplant or incisional corneal surgery and don’t have dense corneal scarring, says Dr. Aldave. It is ideal for patients with keratoconus, in whom the cornea is clear but misshapen, affecting their vision. As with DSEK, the femtosecond laser offers the promise of a decrease in astigmatism because of the precision of the laser, as well as a stronger wound that is more resistant to traumatic opening. ever-expanding number of indications, says Dr. Aldave, who has performed 150 of the procedures, placing him among the three or four highest-volume artificial-corneal-transplant surgeons in the world. “We are finding that patients who previously had no hope of seeing after experiencing repeat corneal-transplant failure now have a viable alternative for reestablishing vision for a meaningful period of time.” Dr. Aldave’s results have been dramatic: Prior to the surgery, 92 percent of patients are not able to read the eye chart and could only count fi ngers, see movements of a hand or see light. One year after surgery, 63 percent of patients have vision between 20/20 and 20/100, a percentage that has remained relatively steady at three-year follow-up and beyond. “Patients who previously had no hope of seeing after experiencing repeat corneal-transplant failure now have a viable alternative (with artificial corneal transplantation) for reestablishing vision for a meaningful period of time.” Two developments in the last decade have significantly improved outcomes and led to the growing popularity of the procedure: modifications in the design of the device and the use of vancomycin and the advent of newer antibiotics that have dramatically reduced the rate of bacterial infections. “Traditionally, artificial- corneal-transplant surgery was considered only for patients who had two or more failed corneal transplants and those who had poor vision in both eyes,” Dr. Aldave explains. “Now, more than half of the patients for whom I perform this procedure have never had a corneal transplant or have had only one prior corneal transplant.” Among the patients in this group are those with corneal- limbal-stem-cell failure, who benefit from the fact that artificial-corneal-transplant recipients don’t require immune-suppression therapy. Image at left shows a patient with corneal swelling and advanced glaucoma. Four years after Descemet’s stripping endothelial keratoplasty (right, the clear round donor cornea can be seen on the posterior surface), the patient continues to enjoy 20/20 corrected visual acuity. Artificial Corneal Transplantation Artificial corneal transplantation is an option for patients who are not candidates for traditional corneal transplantation or who have experienced corneal-transplant failure. The artificial cornea was considered experimental a decade ago, but today is an accepted treatment modality for an 5 UCLA Physicians Update