Study of visible and mid-infrared laser ablation mechanism of PMMA and intraocular lenses: experimental and theoretical results

Laser-polymer interactions have attracted extensive attention both for understanding the inherent basic ablation mechanism and for development of tissue simulators in several biomedical laser applications such as in human ophthalmology. Ablation experiments were performed on polymethylmethacrylate used as cornea tissue simulator and PMMA intraocular lenses. The polymer-ablation mechanism was examined with two different wavelengths and pulse durations. The experiments were conducted with Nd:YAG and Er:YAG solid-state lasers, and the ablation rates were simulated by a mathematical model in each case. Furthermore, to investigate the role of tissue hydration during laser ablation, we performed a set of experiments in which Er:YAG laser ablation of hydrophilic acrylic intraocular lenses, with different H2O and D2O concentrations, was studied. The hydrophilic acrylic lenses with the higher concentration of H2O gave the most satisfactory results regarding both the ablation efficiency and the quality of the ablated craters.