Method for Modifying the Refractive Index of Ocular Tissues

Abstract

A laser system for changing the index of refraction of cornea tissue in a living eye. The laser system comprises a laser that provides laser pulses with a wavelength from 400 nm to 900 nm and a pulse energy from 0.01 nJ to 10 nJ, and a control device for setting the operating parameters of the laser below an optical breakdown threshold of the tissue to avoid photo-disruption and tissue destruction of the tissue, and to direct the laser pulses at the cornea tissue resulting in a change in the index of refraction of the tissue within regions irradiated by the laser pulses.

We claim: 
     
         1 . A laser system for changing the index of refraction of cornea tissue in a living eye comprising:
 a laser that provides laser pulses with a wavelength from 400 nm to 900 nm and a pulse energy from 0.01 nJ to 10 nJ; and   a control device for setting the operating parameters of the laser below an optical breakdown threshold of the tissue to avoid photo-disruption and tissue destruction of the tissue, and to direct the laser pulses at the cornea tissue resulting in a change in the index of refraction of the tissue within regions irradiated by the laser pulses.   
     
     
         2 . The laser system of  claim 1 , wherein the regions irradiated by the laser pulses are in the form of optical elements selected from the group consisting of Bragg gratings, microlens arrays, zone plates, Fresnel lenses, and combinations thereof. 
     
     
         3 . The laser system of  claim 1 , further comprising a wavefront sensor, in communication with the control device, for detecting wavefront aberrations of the eye. 
     
     
         4 . The laser system of  claim 1 , wherein the control device includes the identification and measurement of aberrations resulting from a surgical procedure, and a computer to process aberration information and provide the requisite vision correction to a patient. 
     
     
         5 . The laser system of  claim 3 , wherein the wavefront sensor is selected from the group consisting of Schemer disk, Shack Hartmann, Hartmann screen, Fizeau interferometer and Twymann-Green interferometer. 
     
     
         6 . The laser system of  claim 1 , wherein an optical path of the laser pulse comprises a compensation scheme to provide negative dispersion that compensates for the positive dispersion of the laser pulse due to focusing objectives of the laser. 
     
     
         7 . The laser system of  claim 1 , wherein the laser pulse energy is from 0.01 nJ to 2 nJ. 
     
     
         8 . The laser system of  claim 1 , wherein the laser has a repetition rate from 10 MHz to 500 MHz. 
     
     
         9 . The laser system of  claim 1 , wherein the laser has a pulse width from 10 fs to 100 fs. 
     
     
         10 . The laser system of  claim 1 , wherein the laser has an average power from 10 mW to 100 mW. 
     
     
         11 . The laser system of  claim 7 , wherein the laser has an average power from 10 mW to 100 mW. 
     
     
         12 . The laser system of  claim 11 , wherein the operating parameters are set to induce a 0.001 to 0.03 change in the index of refraction of the cornea tissue within the irradiated region. 
     
     
         13 . The laser system of  claim 1 , wherein the operating parameters are set to induce a 0.001 to 0.03 change in the index of refraction of the cornea tissue within the irradiated region.