Legeais Jm

Noncontact laser penetrating keratoplasty: in-vivo comparative evaluation in rabbit and cat

With their inherent precision and avoidance of tissue deformation, non-contact laser trephines may minimize graft postoperative astigmatism. Laser-cut corneal button geometry surpassed handheld and equaled Hanna and Krumeich vacuum held trephines, without significant endothelium or wound healing differences for linear cuts between laser and metal blades. To compare the laser with metal trephines, we performed 8 mm diameter grafts on 12 rabbits and 12 cats. A new laser system, using an advanced pulsed HF laser coupled to a computer controlled optical delivery system and equipped for quasi-instantaneous simultaneous 8-point corneal marking (200 ns) for precise suture placement at the 5.5 to 10.5 mm diameter and rapid corneal trephination (approximately equals 6 sec), or a new disposable sterile vacuum-assisted Hessburg-Barron (HB) trephine was used in each procedure. Circumferential keratotomies were more accurately and more easily performed with the laser. No statistical differences were found in wound strength and healing. The laser produced a slightly lower astigmatism. These initial results suggest the safety of HF laser corneal marking-trephination and its potential for PK procedures in humans.