Background: One of the most common complications after mechanical penetrating keratoplasty is the occurrence of irregular astigmatism. We developed a method to prepare donor grafts for transplantation applying excimer laser techniques. The quality of the cut edges and exposure time were evaluated.
Materials and methods: The beam of an experimental excimer laser (OPTex, Lambda Physik) was homogenized and guided by an optical system including lenses and scanner mirrors. A special software was used to conduct the laser beam in a circular mode over the surface of the cornea. Corneas from porcine eyes were stabilized in an artificial anterior chamber. Twenty in vitro explants were trephinated applying our method and subsequently investigated by electron microscopy and histology.
Results: All experiments provided regular and smooth cut edges. The average exposure time until perforation was 10.5 min (SD 2.7 min), the diameter of the grafts was 8.0 mm.
Conclusion: The experiments showed the possibility of non-contact trephination and generation of smooth cut edges with a rotating focussed excimer laser beam in a porcine cornea model. A major advantage of the system is the possibility of customized "tailored" grafts.