DYNAMICS OF ARF EXCIMER LASER-INDUCED CAVITATION BUBBLES IN GEL SURROUNDED BY A LIQUID-MEDIUM

Background and Objective: Cavitation bubbles have been shown to be the driving force of tissue cutting in 193 nm ArF excimer laser-based vit reoretinal microsurgery. In the present work we investigate the dynami cs of cavitation bubbles inside a gelatin gel in a saline environment using fast flash microphotography. Study Design/Materials and Methods: The screening influence of the saline medium was found to restrict th e maximal distance between the tip and the tissue at which cavitation bubbles are created to <100 mu m at an energy fluence up to 0.3 J/cm(2 )/pulse (the maximal energy fluence applied in vitreoretinal surgery). Results and Conclusion: Single laser pulses did not cause disruption of gelatin at an energy fluence of up to 0.4 J/cm(2)/pulse. During the application of repetitive pulses small insoluble, gas-containing bubb les were produced and often trapped between the tip and the tissue, Th ey completely changed the shape of the subsequent cavitation bubbles a nd caused deep crater formation in the gel. (C) 1997 Wiley-Liss, Inc.