Femtosecond Laser Assisted Keratoplasty
Condition: Keratoconus
MeSH terms: Keratoconus
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      Penetrating keratoplasty (PKP) or full-thickness corneal transplantation is a common and
      highly successful method to restore vision decreased by corneal opacification. Surgery is
      performed by using round trephine blades to create matched circumferential incisions in both
      the diseased cornea and the donor cornea. Several types of blades are currently available to
      create uniform corneal cuts. The donor tissue graft is then secured in place with sutures
      which are usually removed postoperatively after one to two years. 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.

      Although the femtosecond laser has been approved by the FDA for use in corneal transplants,
      it has not been compared to standard corneal transplant techniques. This pilot study will
      help us determine optimal femtosecond laser spot size, separation, fluency, and energy which
      result in the best graft-host fit. Surgical eligibility criteria, including preoperative
      diagnoses, as well as possible associated medical and ophthalmic conditions for the eventual
      multi-center study will be defined. Primary outcome measures, which include corneal
      refractive power measurements, serial endothelial-cell counts to assess endothelial survival
      and vision-specific quality of life surveys, will be evaluated. The specific aim is to
      investigate postoperative physiology and biomechanics after FLAK in human eyes. The
      significance is that FLAK presents corneal surgeons with an opportunity to avoid some
      problems of PKP and offers a safer and more precise approach to treating visually disabling
      diseases secondary to corneal opacification.
    

Intervention name(s): Femtosecond laser assisted keratoplasty; PKP
Intervention type(s): Procedure; Procedure
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment