Comparison of laser phacovaporization using the Er-YAG and the Er-YSGG laser

R. P. Gailitis, S. W. Patterson, M. A. Samuels, K. Hagen, Q. Ren and G. O. Waring 3rd
Eye Care and Surgery Center of Fort Lauderdale, FL 33304.

OBJECTIVE--To study the interaction of the erbium (Er)-YAG (2.94 microns) and the Er-YSGG (2.79 microns) lasers with the human crystalline lens tissue. METHODS--Fresh human crystalline lens sections were used to measure the photovaporization threshold, rate, and damage zone of the two lasers. RESULTS--We found the photovaporization threshold for the Er-YAG and the Er-YSGG lasers to be 1.4 J/cm2 and 5.5 J/cm2, respectively. At 10 J/cm2, the photovaporization rate is 67.9 microns per pulse for the Er-YAG laser and 18.4 microns per pulse for the Er-YSGG laser. The increased rate of photovaporization as a function of radiant energy for the Er-YAG laser is almost twice that for the Er-YSGG. Damage zones for the Er-YAG laser ranged from 4 to 9 microns compared with 10 to 22 microns for the Er-YSGG. CONCLUSIONS--It is apparent that both lasers can adequately photovaporize human crystalline lens tissue and should be further studied for this purpose.