System and Method for Correcting Higher Order Aberrations with Changes in Intrastromal Biomechanical Stress Distributions

Abstract

A method for correcting higher order aberrations in an eye requires Laser Induced Optical Breakdown (LIOB) of stromal tissue. In detail, the method identifies at least one volume of stromal tissue in the eye, with each volume defining a central axis parallel to the visual axis of the eye. Thereafter, a pulsed laser beam is focused to a focal spot in each volume of stromal tissue to cause LIOB of stromal tissue at the focal spot. Further, the focal spot is moved through the volume of stromal tissue to create a plurality of incisions centered about the respective central axis of the volume. As a result, a predetermined selective weakening of the stroma is caused for correction of the higher order aberration.

1 - 17 . (canceled) 
     
     
         18 . A method for correcting unsymmetrical aberrations in an eye, wherein the eye defines a visual axis and the method comprises the steps of:
 identifying at least one volume of stromal tissue in the eye, wherein the volume of tissue defines a central axis located at a distance from the visual axis of the eye and oriented substantially parallel thereto;   focusing a pulsed laser beam to a focal spot in the volume of stromal tissue to cause Laser Induced Optical Breakdown (LIOB) of stromal tissue at the focal spot; and   moving the focal spot of the pulsed laser beam through the volume of stromal tissue to create at least one incision centered about the respective central axis of the volume, to cause a predetermined selective weakening of the stroma for correction of the unsymmetrical aberration.   
     
     
         19 . A method as recited in  claim 18  wherein the unsymmetrical aberration is astigmatism. 
     
     
         20 . A method as recited in  claim 18  wherein the at least one incision forms an arc segment on a cylindrical surface centered on the central axis. 
     
     
         21 . A method as recited in  claim 18  wherein each volume of stromal tissue is bounded by Bowman's membrane and wherein each incision is at least ten microns from Bowman's membrane. 
     
     
         22 . A method as recited in  claim 21  wherein each volume of stromal tissue is further bounded by the endothelium and wherein each incision is at least 150 microns from the endothelium. 
     
     
         23 . A method as recited in  claim 18  wherein the at least one volume of stromal tissue is two volumes of stromal tissue. 
     
     
         24 . A method as recited in  claim 18  wherein the at least one incision is one incision. 
     
     
         25 . A method as recited in  claim 18  wherein each incision is created to form a rectangular cylinder centered on the respective central axis. 
     
     
         26 . A method for correcting unsymmetrical aberrations in an eye, wherein the eye defines a visual axis and the method comprises the steps of:
 identifying at least one volume of stromal tissue in the eye, wherein the volume of tissue defines a central axis located at a distance from the visual axis of the eye and oriented substantially parallel thereto, and wherein each volume has an anterior surface located at least ten microns from Bowman's membrane and a posterior surface located approximately 150 microns from the endothelium of the cornea;   focusing a laser beam to a focal spot in the volume of stromal tissue to cause Laser Induced Optical Breakdown (LIOB) of stromal tissue at the focal spot; and   moving the focal spot of the laser beam within the volume of stromal tissue to create at least one incision centered about the respective central axis of the volume, to cause a predetermined selective weakening of the stroma for correction of an unsymmetrical aberration.   
     
     
         27 . A method as recited in  claim 26  wherein the unsymmetrical aberration is astigmatism. 
     
     
         28 . A method as recited in  claim 26  wherein the at least one incision forms an arc segment on a cylindrical surface centered on the central axis. 
     
     
         29 . A method as recited in  claim 26  wherein the at least one volume of stromal tissue is two volumes of stromal tissue. 
     
     
         30 . A method as recited in  claim 26  wherein the at least one incision is one incision. 
     
     
         31 . A method as recited in  claim 26  wherein each incision is created to form a rectangular cylinder centered on the respective central axis. 
     
     
         32 . A system for correcting unsymmetrical aberrations in an eye, wherein the eye defines a visual axis, the system comprising:
 a means for identifying at least one volume of stromal tissue in the eye, wherein the volume of tissue defines a central axis located at a distance from the visual axis of the eye and oriented substantially parallel thereto;   a means for generating a pulsed laser beam, wherein the duration of each pulse in the beam is less than one picosecond;   a means for focusing the laser beam to a focal spot in each volume of stromal tissue to cause Laser Induced Optical Breakdown (LIOB) of stromal tissue at the focal spot; and   a means for moving the focal spot of the laser beam within each volume of stromal tissue to create at least one incision centered about the respective central axis of each volume, to cause a predetermined selective weakening of the stroma for correction of the unsymmetrical aberration.   
     
     
         33 . A system as recited in  claim 32  wherein the unsymmetrical aberration is astigmatism. 
     
     
         34 . A system as recited in  claim 32  wherein the at least one incision forms an arc segment on a cylindrical surface centered on the central axis. 
     
     
         35 . A system as recited in  claim 32  wherein each volume of stromal tissue has an anterior surface located at least ten microns from Bowman's membrane and a posterior surface located approximately 150 microns from the endothelium of the cornea. 
     
     
         36 . A system as recited in  claim 32  wherein the at least one volume of stromal tissue is two volumes of stromal tissue. 
     
     
         37 . A system as recited in  claim 32  wherein the at least one incision is one incision.