Laser thermokeratoplasty: An in vitro and in vivo study by means of a continuous wave Mid-IR laser diode

Laser thermokeratoplasty (LTK) has been performed with a continuously emitting, tunable laser diode at 1.86 μm. A study on enucleated porcine eyes was conducted in order to demonstrate the feasibility of this laser source for LTK and to determine the useful irradiation modalities. Refractive changes achieved with different application systems and a standard coagulation pattern, consisting of 8 spots on a 6 mm ring, were measured. The most promising sets of parameters were carrried out in a first animal study with mini pigs. Initial refractive changes up to 6 D could be achieved in vitro and in vivo with laser powers between 120 mW and 200 mW and irradiation times of several seconds. In conclusion, the laser diode used seems to be the optimal source for a clinical LTK system.