Electrical alternative to pulsed lasers in vitreoretinal surgery

Cavitation bubbles have been shown to be a driving force of tissue cutting during pulsed laser applications in vitreoretinal surgery. Such bubbles are generated by fast overheating of water due to laser radiation absorption in either water or in tissue or due to the dielectric breakdown in the focused laser beam. An alternative approach proposed in this paper is the generation of cavitation bubbles by the fast overheating of the liquid conductive medium by a short pulse of electric current. An electrical system based on a tapered microelectrode has been developed for generation of a high voltage sub-microsecond discharge in physiological medium. The dynamics of the associated cavitation bubbles was similar to that observed with ns-pulsed fiber-delivered lasers. A highly localized zone of power dissipation - about 20 μm in size - resulted in a low threshold energy of cavitation bubble generation - about 3 μJ - in comparison to the laser-based intraocular surgical systems. The minimal distance of safe applications of this device was measured in-vitro and in-vivo as a function of energy and was compared with the ArF excimer and IR laser-based systems. The proposed device can become a convenient and a cost- effective alternative to lasers in vitreoretinal microsurgery.