Sixty-Kilohertz Femtosecond Laser–Assisted Endothelial Keratoplasty: Clinical Results and Stromal Bed Quality Evaluation

Abstract

To evaluate preliminary clinical results and lamellar and side cut obtained with a 60-kHz femtosecond laser (IntraLase) using a new software designed to create penetrating cuts for keratoplasty to perform the donor and recipient dissection in femtosecond laser-assisted endothelial keratoplasty. Prospective interventional case series. A femtosecond laser set in a raster spot pattern was used to create the posterior lamellar dissection and posterior side cut in 4 donor corneas and in 4 recipient human eyes of 4 patients with endothelial decompensation. The laser cut was performed to obtain a 150-μm thick and 9-mm wide posterior lamellar disk from the donor and the recipient eyes. Postoperatively, patients underwent slit-lamp examination and Snellen visual acuity evaluation, Visante optical coherence tomography, optical pachymetry, and endothelial microscopy analysis. Three residual donor corneas were analyzed by scanning electron microscopy and transmission electron microscopy to observe the stromal bed surface, the side cut, and the effects of the laser dissection on the cornea ultrastructure. Thickness of the implanted donor lamella, adhesion and clarity of the transplanted cornea in the postoperative follow-up, and smoothness of the interface. All the patients showed good adhesion and fit of the donor disk to the recipient and a circle side cut observed at the slit-lamp examination. Visante optical coherence tomography evaluation confirmed the adhesion and the precalibrated thickness of the implanted lamella. A good corneal transparency was achieved within the first 2-3 weeks. The scanning electron microscopy analysis showed a smooth stromal residual surface and a precise side cut. The transmission electron microscopy images showed that the laser randomly modified the structural design of the collagen fibers for approximately 10-μm depth, although below a regular stromal structure was maintained. The 60-kHz IntraLase femtosecond laser creates a smooth stromal bed and precise side cut for endothelial keratoplasty. The posterior lamellar cut performed at the same depth in both the donor and the recipient makes it possible to create a corneal disk from the donor that fits exactly with the cut in the recipient.