A device and a method for the femtosecond laser surgery of tissue, especially in the vitreous humor of the eye. The device includes an ultrashort pulse laser with pulse widths in the range of approximately 10 fs-1 ps, especially approximately 300 fs, pulse energies in the range of approximately 5 nJ-5 μJ, especially approximately 1-2 μJ and pulse repetition rates of approximately 10 kHz-10 MHz, especially 500 kHz. The laser system is coupled to a scanner system which allows the spatial variation of the focus in three dimensions (x, y and z). In addition to the therapeutic laser/scanner optical system, the device includes a navigation system.