Device and method for cutting a cornea or a crystalline lens

Abstract

A device for cutting human or animal tissue including a femtosecond laser that can emit a L.A.S.E.R. beam in the form of impulses. The device directs and focuses the beam onto or into the tissue for the cutting thereof. The device further includes and element to shape the L.A.S.E.R. beam, positioned in the trajectory of the beam, and to modulate the energy distribution of the L.A.S.E.R. beam in the focal plane thereof, corresponding to the cutting plane.

1 . A medical device configured to cut a human or animal tissue, said medical device comprising:
 a femtosecond laser which emits a laser beam as pulses,   shaping means, downstream of the femtosecond laser, which generate a single modulated laser beam by modulating the phase of the wave front of the laser beam, and   means which direct and focus said single modulated laser beam in a focal plane extending on or within the human or animal tissue,   wherein said shaping means modulate the phase of the wave front of the laser beam according to a modulation set value calculated for distributing the energy of the single modulated laser beam in at least two impact points in the focal plane, each impact point generating a cavitation bubble on or within the human or animal tissue.   
     
     
         2 . The medical device according to  claim 1 , which further comprises control means which controls the shaping means by applying the modulation set value to said shaping means. 
     
     
         3 . The medical device according to  claim 1 , wherein the shaping means are in the form of a spatial light modulator with liquid crystals. 
     
     
         4 . The medical device according to  claim 3 , wherein the modulation set value is a two-dimensional image displayed on the spatial light modulator, wherein said two-dimensional image causes an uneven spatial phase shift of the laser beam by reflection, said uneven spatial phase shift inducing distribution of energy of the single modulated laser beam in at least two impact points in the focal plane. 
     
     
         5 . The medical device according to  claim 3 , wherein the modulation set value is a two-dimensional grey level image. 
     
     
         6 . The medical device according to  claim 1 , wherein the modulation set value is calculated independently of the form of the wave front of the laser beam prior to modulation. 
     
     
         7 . The medical device according to  claim 1 , wherein the energy of the single modulated laser beam is distributed in the focal plane in a plurality of distinct impact points forming a pattern. 
     
     
         8 . The medical device according to  claim 7 , wherein the impact points of the pattern are uniformly spaced over the two dimensions of the focal plane so as to form a grid pattern of laser spots. 
     
     
         9 . The medical device according to  claim 7 , which further comprises an optical mirror system pivoting about at least two axes for displacing the pattern in the focal plane in a plurality of distinct positions. 
     
     
         10 . A method of cutting-out a human or animal tissue by use of a medical device comprising a femtosecond laser which emits a laser beam as pulses, shaping means which generate a single modulated laser beam, and means which direct and focus said single modulated laser beam in a focal plane extending on or within the human or animal tissue,
 wherein the method comprises the following steps:
 applying a phase modulation set value to the shaping means, wherein the modulation set value is calculated to distribute the energy of the laser beam in at least two impact points in the focal plane, 
 modulating the phase of the wave front of the laser beam with the shaping means to generate the single modulated laser, wherein the shaping means are positioned on the trajectory of said laser beam, 
 directing and focusing the single modulated laser beam in the focal plane extending on or within the human or animal tissue.