Femtosecond Laser Assisted Keratoplasty

Penetrating keratoplasty (PKP) is corneal transplantation performed by using round trephine blades to create matched circumferential incisions in both the diseased cornea and the donor cornea. The donor tissue graft is then secured in place with sutures which are usually removed postoperatively.The primary surgical goals are the preservation of a clear graft and improvement of vision. Surgical outcomes are limited by donor-recipient junction mismatch, astigmatism, rejection, infection and wound dehiscence. The femtosecond laser is a focusable, infrared laser capable of cutting tissue at various depths and in a range of patterns, and is currently being used to create corneal lamellar flaps in LASIK surgery. The laser parameters can be adjusted for submicron precision in cutting desired diameters, depths and shapes in the cornea, with minimal collateral injury. This technology is now capable of creating full-thickness corneal trephinations with customized locking edges at the graft-host junction between the donor and recipient corneas in Femtosecond Laser-Assisted Keratoplasty (FLAK). This approach may allow for better wound junction of the donor and recipient corneas, which in turn may also significantly reduce astigmatism, improve wound healing and visual recovery. This pilot study will help us determine optimal femtosecond laser spot size, separation, fluence, and energy which result in the best graft-host fit. The specific aim is to investigate postoperative physiology and biomechanics after FLAK in human eyes.