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May 1993

Comparison of Laser Phacovaporization Using the Er-YAG and the Er-YSGG Laser

Author Affiliations

From the Eye Care and Surgery Center of Fort Lauderdale, Fla (Dr Gailitis); Laser Atlanta, Norcross, Ga (Messrs Patterson and Samuels); San Bernardino (Calif) County Medical Center (Dr Hagen); Bascom Palmer Eye Institute, Miami, Fla (Dr Ren); and Department of Ophthalmology, Emory University, Atlanta, Ga (Dr Waring). Mr Samuels and Mr Patterson are president and vice president, respectively, of Laser Atlanta. They both have a financial interest in the development of the Er-YAG and Er-YSGG lasers. Dr Gailitis is a paid consultant for Lasersight Inc, Orlando, Fla, which is also investigating the use of solid state lasers for cataract surgery. None of the other authors have financial interests in the material presented.

Arch Ophthalmol. 1993;111(5):697-700. doi:10.1001/archopht.1993.01090050131042

• Objective.  —To study the interaction of the erbium (Er)-YAG (2.94 μm) and the Er-YSGG (2.79 μm) 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 μm per pulse for the Er-YAG laser and 18.4 μm 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 μm compared with 10 to 22 μm 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.