中赤外パルスレーザーによるLTKの基礎的検討: Ho: YAG レーザーとTm: YAG レーザーとの比較

Abstract

To propose Tm: YAG laser LTK (Laser Thermal Keratoplasty), we compared the porcine corneal coagulation depthes produced by Ho: YAG laser (wavelength=2.10 μm) and Tm: YAG laser (wavelength=2.01μm) in vitro. The radiant exposures of both lasers varied from 2.5to 22J/cm2 and the number of laser pulses ranged from single shot to 20 shots. The corneal coagulation depthes were as thick as the human corneal thickness (0.7mm) for Ho: YAG laser and less than that for Tm: YAG laser in the case of single shot. The corneal coagulation depthes were thicker than the penetration depth of either lasers. In the case of varing the number of laser pulses, the relation between the corneal coagulation depthes and the radiant exposures was independent of the number of laser pulses for Tm: YAG laser (2 Hz), however the corneal coagulation depthes increased with the number of laser pulses for Ho: YAG laser (4 Hz). The energy efficiency of the coagulation gave the reason why the depth of corneal coagulation were thicker than the penetration depth. These results demonstrated the capability of Tm: YAG laser LTK without endothelium injury.