ELECTRICAL ALTERNATIVE TO PULSED FIBER-DELIVERED LASERS IN MICROSURGERY

An electrical system based on a tapered microelectrode has been develo ped for generation of high voltage sub-microsecond discharge in physio logical medium. Different types of the resulting pulses of current are investigated as well as the dynamics of the associated cavitation bub bles. A highly localized zone of power dissipation-about 20 mu m in si ze-results in a low threshold energy of cavitation bubble generation-a bout 3 mu J-in comparison to laser-based intraocular microsurgical ins trumentation with fiber delivery systems. Cavitation bubble dynamics r esulting from the electric discharge is similar to that observed with ns-pulsed fiber-delivered lasers in strongly absorbing liquid medium. Efficiency of the pulse energy conversion to the bubble energy is abou t 12%, which is lower than the best results obtained with losers. In s pite of that, due to the low threshold energy, cavitation bubbles requ ired for effective cutting of soft tissue can be generated at energies lower than that used in laser instrumentation with fiber-based delive ry systems, The proposed device has a potential to become a convenient and a cost-effective alternative to such lasers in vitreoretinal micr osurgery. (C) 1997 American Institute of Physics.