초록 ▼

A method for performing intrastromal ophthalmic laser surgery requires Laser Induced Optical Breakdown (LIOB) of stromal tissue without compromising Bowman's capsule (membrane). In detail, the method creates cuts in the stroma along planes radiating from the visual axis of the eye. Importantly, thes

A method for performing intrastromal ophthalmic laser surgery requires Laser Induced Optical Breakdown (LIOB) of stromal tissue without compromising Bowman's capsule (membrane). In detail, the method creates cuts in the stroma along planes radiating from the visual axis of the eye. Importantly, these cuts are all distanced from the visual axis. The actual location and number of cuts in the surgery will depend on the degree of visual aberration being corrected. Further, the method may include the additional step of creating cylindrical cuts in the stroma. The radial cuts and cylindrical cuts may be intersecting or non-intersecting depending on the visual aberration being treated.

대표청구항 ▼

What is claimed is: 1. A method for performing intrastromal ophthalmic laser surgery, wherein the cornea defines a visual axis and has a thickness “T”, and wherein the method comprises the steps of: generating a pulsed laser beam, wherein the duration of each pulse in the beam is less

What is claimed is: 1. A method for performing intrastromal ophthalmic laser surgery, wherein the cornea defines a visual axis and has a thickness “T”, and wherein the method comprises the steps of: generating a pulsed laser beam, wherein the duration of each pulse in the beam is less than approximately one picosecond; directing and focusing the beam onto a series of focal spots in the stroma for Laser Induced Optical Breakdown (LIOB) of stromal tissue at each focal spot to weaken stromal tissue by redistributing biomechanical forces in the stroma; and moving the focal spot in the stroma to create a pattern of unconnected radial cuts, wherein each radial cut is made coplanar with the visual axis to remove an insignificant amount of tissue to substantially maintain the integrity of the cornea and is defined by an azimuthal angle θ, wherein each radial cut has an anterior end and a posterior end extending from an inner radius “ri” to an outer radius “ro”, with both “ri” and “ro” being measured from the visual axis, with the posterior end of each radial cut being located in the stroma within less than approximately 0.9 T from an anterior surface of the eye, and the anterior end of the radial cut is located in the stroma more than at least eight microns in a posterior direction from Bowman's capsule, and further wherein each radial cut has a thickness of approximately two microns, with the weakened stromal tissue being responsive to an intraocular pressure for surgically reshaping the cornea. 2. A method as recited in claim 1 wherein the pattern of radial cuts is formed from eight cuts situated about the visual axis, wherein each cut is 45 degrees from an adjacent cut. 3. A method as recited in claim 1 wherein the pattern of radial cuts is formed from twelve cuts situated about the visual axis, wherein each cut is 30 degrees from an adjacent cut. 4. A method as recited in claim 1 wherein the pattern of radial cuts is formed from sixteen cuts situated about the visual axis, wherein each cut is 22.5 degrees from an adjacent cut. 5. A method as recited in claim 1 wherein the pattern of radial cuts is formed from two sets of at least three cuts, and wherein the sets are diametrically opposed from one another. 6. A method as recited in claim 5 further comprising the step of moving the focal spot in the stroma to create a plurality of cylindrical cuts, wherein each cylindrical cut is made on portions of a respective cylindrical surface, wherein the respective cylindrical surfaces are concentric and are centered on the visual axis of the cornea, and further wherein each cylindrical surface has an anterior end and a posterior end, with the posterior end of each cylindrical cut being located in the stroma less than approximately 0.9 T from an anterior surface of the eye, and with the anterior end of each cylindrical cut being located in the stroma more than at least eight microns in a posterior direction from Bowman's capsule in the cornea. 7. A method as recited in claim 6 wherein the radial cuts intersect the cylindrical cuts. 8. A method as recited in claim 6 wherein the radial cuts and the cylindrical cuts are non-intersecting. 9. A method as recited in claim 6 wherein the portions of the cylindrical surfaces subjected to LIOB define diametrically opposed arc segments wherein each arc segment extends through an arc in a range between five degrees and one hundred and sixty degrees. 10. A method as recited in claim 5 further comprising the steps of: performing LIOB in portions of an annular layer, wherein the layer has an inner diameter “di” and an outer diameter “do”, and has a thickness of about one micron; creating a plurality of layers adjacent to each other; and locating the plurality of layers in the stroma between less than approximately 0.9 T from the anterior surface of the eye and at least eight microns in a posterior direction from Bowman's capsule. 11. A method for performing intrastromal ophthalmic laser surgery wherein the cornea defines a visual axis and has a thickness “T”, and wherein the method comprises the steps of: identifying an operational volume in the stroma, wherein the operational volume is centered on the visual axis and extends radially therefrom through a distance “rv”, and further wherein the operational volume has an anterior surface located at least eight microns in a posterior direction from Bowman's capsule (membrane) of the cornea and a posterior surface located at less than approximately 0.9 T from the anterior of the cornea; focusing a pulsed laser beam to a focal point in the operational volume for LIOB of stromal tissue, wherein each pulse of the laser beam has a duration less than one picosecond to weaken stromal tissue by redistributing biomechanical forces in the stroma; and moving the focal spot within the operational volume to create a pattern of unconnected radial cuts, wherein each radial cut is made coplanar with the visual axis to remove an insignificant amount of tissue to substantially maintain the integrity of the cornea and is defined by an azimuthal angle θ, wherein each radial cut has an anterior end and a posterior end extending from an inner radius “ri” to an outer radius “ro”, with both “ri” and “ro” being measured from the visual axis, with the weakened stromal tissue being responsive to an intraocular pressure for surgically reshaping the cornea. 12. A method as recited in claim 11 wherein the pattern of radial cuts is formed from eight cuts situated about the visual axis, wherein each cut is 45 degrees from an adjacent cut. 13. A method as recited in claim 11 wherein the pattern of radial cuts is formed from twelve cuts situated about the visual axis, wherein each cut is 30 degrees from an adjacent cut. 14. A method as recited in claim 11 wherein the pattern of radial cuts is formed from sixteen cuts situated about the visual axis, wherein each cut is 22.5 degrees from an adjacent cut. 15. A method as recited in claim 11 wherein the pattern of radial cuts is formed from two sets of at least three cuts, and wherein the sets are diametrically opposed from one another. 16. A method as recited in claim 15 further comprising the step of moving the focal spot within the operational volume to create a plurality of cylindrical cuts, wherein each cylindrical cut is made on portions of a respective cylindrical surface, wherein the respective cylindrical surfaces are concentric and are centered on the visual axis of the cornea, and further wherein each cylindrical surface has an anterior end and a posterior end. 17. A method as recited in claim 16 wherein the portions of the cylindrical surfaces subjected to LIOB define diametrically opposed arc segments wherein each arc segment extends through an arc in a range between five degrees and one hundred and sixty degrees. 18. A method as recited in claim 17 wherein the radial cuts intersect the cylindrical cuts. 19. A method as recited in claim 16 wherein the radial cuts and the cylindrical cuts are non-intersecting. 20. A method for performing intrastromal ophthalmic laser surgery, wherein the cornea defines a visual axis and has a thickness “T”, and wherein the method comprises the steps of: generating a pulsed laser beam, wherein the duration of each pulse in the beam is less than approximately one picosecond; directing and focusing the beam onto a series of focal spots in the stroma for Laser Induced Optical Breakdown (LIOB) of stromal tissue at each focal spot to weaken stromal tissue by redistributing biomechanical forces in the stroma; and selecting a plurality of unconnected cuts from the group consisting of (a) a first plurality of unconnected cylindrical cuts made on portions of cylindrical surfaces concentric on a first axis parallel to the visual axis and a second plurality of cylindrical cuts made on portions of cylindrical surfaces concentric on a second axis parallel to the visual axis and opposite the first axis, (b) a centered plurality of unconnected cylindrical cuts concentric on the visual axis, and (c) a plurality of unconnected radial cuts, wherein each plurality of cuts has a posterior end and an anterior end, with the posterior end of each cylindrical cut being located in the stroma less than approximately 0.9 T from an anterior surface of the eye, with the anterior end of each cylindrical cut being located in the stroma more than at least eight microns in a posterior direction from Bowman's capsule in the cornea, with the posterior end of each radial cut being located in the stroma within less than approximately 0.9 T from the anterior surface of the eye, and with the anterior end of the radial cut being located in the stroma more than at least eight microns in a posterior direction from Bowman's capsule, wherein each radial cut extends from an inner radius “ri” to an outer radius “ro”, with both “ri” and “ro” being measured from the visual axis, and wherein each radial cut has a thickness of approximately two microns, is made coplanar with the visual axis, and is defined by an azimuthal angle θ; and moving the focal spot in the stroma to create the selected plurality of unconnected cuts to remove an insignificant amount of tissue to substantially maintain the integrity of the cornea, with the weakened stromal tissue being responsive to an intraocular pressure for surgically reshaping the cornea.