Scott W. Patterson

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

Future advances in cataract surgery aim to remove the crystalline lens through a small opening such that the capsular bag, once devoid of lens epithelial cells, may be refilled with a clear polymer which may exhibit the elastic properties of a young lens and restore accommodation. Several different lasers are currently being investigated for laser cataract surgery including the excimer, pulsed visible and short infrared, and mid infrared lasers. Taking advantage of the strong water absorption peak at 2.94 micrometers , we have investigated the laser tissue interaction of the Er:YAG (2.94 micrometers ) and Er:YSGG (2.79 micrometers ) which have water absorption coefficients of 13,000 cm-1 and 7,000 cm-1, respectively. We have devised a delivery system which measures the ablation time versus radiant energy through a known thickness on a lens nucleus in free air for these two wavelengths. The current presentation compares the ablation rates versus radiant exposure of these two lasers in human lens nuclei. We also show the histopathology from ablated lenses of these two different wavelengths at different radiant exposures. Integration with fiberoptics and clinical applications is discussed.