Study of ns and fs pulse laser-induced effects in biological-tissue models and corneal tissue

This work presents a study of photo-induced effects in biological-tissue models made from agar gel and on porcine cornea samples. We used a Nd:YAG (5 ns) and a Ti:sapphire (90fs) lasers to irradiate the samples. The main objective in this study is to understand some aspects of the interaction between pulsed lasers and biological tissue, of especially interest for us are vascular and corneal tissues. Our research includes laser heating of vascular-like tissue and laser-induced cavitation bubble formation in cornea. We will present results of laser heating of vascular-like tissue, and its dependence on laser fluence and pulse duration. Also, we will present results of cavitation bubble formation for agar gel and corneal tissues. Our results show that there exists a well determined threshold fluence for the onset of bubble formation; the laser-induced bubbles on agar gel and cornea can be permanent or transient depending on the laser irradiation parameters. Some interesting dermatological and ophthalmic applications related to the above effects will be suggested and discussed throughout this work. © 2006 American Institute of Physics.

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