TPEF MICROSCOPY FOR VISUALIZATION OF INTRATISSUE MICROMACHINING ON HUMAN CRYSTALLINE LENSES

INTRODUCTION Presbyopia is an age related disease mainly consisting in the progressive loss of elasticity of the crystalline lens of the eye. This leads to a decrease on the ability of accommodation and a subsequent difficulty to focus on near objects. Among the common treatments one could find correcting lenses, contact lenses or new surgical procedures such as the implantation of intraocular lenses or refractive surgery on the cornea. However the results obtained are partially satisfactory, opening the opportunity for further development of new strategies. In that sense lentotomy techniques [1] has been proved to produce a softening of the crystalline lens after laser ablation. In those experiments NIR lasers at 1064 nm wavelength and 100 kHz repetition rate were used. METHODS The aim of the present study is to perform laser intra tissue ablation of the crystalline lens from human donors using infrared femtosecond laser with high repetition rate (80 MHz at 860 nm wavelength). We have used a custom build multimodal non-linear microscopy platform modified to work as a nano-surgery scalpel. RESULTS Using a single femtosecond laser system, complex patterns in 2D and 3D configuration have been imprinted inside human donor lenses (see figure 1). The produced results have been analyzed through transmitted infrared light and Two-Photon Excitation Fluorescence (TPEF) microscopy. We have observed an increase of the TPEF signal on the targeted regions. In addition, we found that the caused damaged is highly confined without any apparent effect on the surrounding tissue.