Abstract
The invention contemplates controlled ablation of the cornea, using ultraviolet laser radiation, wherein irradiated flux density and exposure time are so controlled as to achieve desired depth of the ablation. Sculpturing action results from controlled change of projected laser-spot size, in the course of a given treatment, wherein, in one illustrative case, projected laser-spot size ranges from a maximum which covers the entire area to be treated, down to a predetermined minimum tolerable size, wherein cornea-curvature change is myopia-corrective. Further illustrative techniques and situations are also disclosed, for achievement of hyperopia correction, for astigmatism correction, and in connection with corneal-transplant operations.
Filing date: Jul 31, 1986
Issue date: Mar 8, 1988
Inventor: Francis A. L'Esperance, Jr.
Assignee: LRI L.P.
Primary Examiner: David Shay
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What is claimed is:
1. Sculpture apparatus for curvature-correcting operation upon the anterior surface of the cornea of an eye, comprising laser means producing an output beam in the ultraviolet portion of the electromagnetic spectrum, controllable means for variably limiting the sectional area of said beam at impingement on the cornea, the area variation being over a range which at least includes a maximum curvature-correcting area to be ablated and being symmetrical with respect to a beam-projection axis which coincides with the optical axis of the eye, the intensity of laser-spot projection being limited per unit time to ablate but a fraction of a predetermined maximum depth of ablation into the stroma region of the cornea, and control means connected to said laser means and to said controllable means, for so correlating laser-beam impingement at the cornea with variation of the sectional area of said beam as to effect a diopter change at the cornea.
2. Apparatus for performing ophthalmological surgery by selective ablation of the anterior surface of the cornea of an eye of a patient with penetration into the stroma to achieve a volumetric removal of tissue within the optically functioning area of the cornea, said apparatus comprising laser means producing on an optical axis an output beam in the ultraviolet portion of the electromagnetic spectrum, optical means on said axis including a zoom lens with a zoom drive for variably setting the sectional area of said beam to a spot on the cornea, the area variation of said spot being within a maximum area to be ablated and being symmetrical with respect to a beam-projection axis which coincides with the optical axis of the eye, the intensity of laser-beam projection being limited per unit time to ablate but a fraction of a predetermined maximum ablation into the stroma region of the cornea, and programmable means with coordinating control connections to said laser means and to said zoom drive, whereby the integrated time of laser-beam impingement at the cornea may be so correlated with variable confined-spot area as to effect a diopter-reducing change at the cornea.
3. Sculpture apparatus for curvature-correcting operation upon the anterior surface of the cornea of an eye, comprising laser means producing an output beam in the ultraviolet portion of the electromagnetic spectrum, reflector means for reflecting said beam and for variably limiting the area of said beam at impingement on the cornea, said reflector means including actuating means for varying the reflector area thereof, the range of reflector-area variation at least including a maximum curvature-correcting area to be ablated and being symmetrical with respect to a beam-projection axis which coincides with the optical axis of the eye, the intensity of laser-spot projection being limited per unit time to ablate but a fraction of a predetermined maximum depth of ablation into the stroma region of the cornea, and means including a microprocessor with coordinating control connections to said laser means and to said actuating means, for so correlating laser-beam impingement at the cornea with variation of reflected-spot area as to effect a diopter change at the cornea.
4. Sculpture apparatus according to claim 3, in which said reflector means is operative to provide cornea exposure at a central circular area and at a plurality of similarly shaped but greater areas, said areas being concentric, whereby the diopter change may be myopia-correcting.
5. Sculpture apparatus according to claim 3, in which said reflector means is operative to provide cornea exposure at said maximum area of curvature correction and at a plurality of similarly shaped but lesser areas, said areas being annular and characterized by progressively changing inner radius, whereby the diopter change may be hyperopia-correcting.
6. Sculpture apparatus according to claim 5, in which the range of reflector-area variation is larger than said maximum curvature-correcting area to thereby determine an outer annulus of laser-beam projection surrounding said maximum curvature-correcting area, said actuating means also varying the outer diameter of said outer annulus such that said outer-diameter variation (i) commences at substantially the outer diameter of said curvature-correcting area and (ii) proceeds with outward diameter expansion.
7. Sculpture apparatus according to claim 3, in which said reflector means is operative to provide cornea exposure at a narrow elongate rectangular area centered on the optical axis of the eye and spanning said maximum area, plural said reflector means being further operative to provide cornea exposure at similarly shaped but greater areas, said areas being elongate rectangular and of varying width which is symmetrical about the elongation direction of said narrow area, whereby the diopter change may be astigmatism-correcting.
8. Sculpture apparatus according to claim 7, wherein orientation of the elongate direction of said areas is variable.
9. Sculpture apparatus according to claim 3, in which said reflector means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, being defined by a constant outer diameter and by an inner diameter which varies to a fixed minimum inner diameter, whereby the diopter change may be myopia-correcting in a sculpted Fresnel annulus defined by said constant outer diameter and by said fixed minimum inner diameter.
10. Sculpture apparatus according to claim 3, in which said reflector means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, being defined by a constant inner diameter and by a varying outer diameter which is intermediate said inner diameter and the outer diameter of said maximum area, whereby the diopter change may be hyperopia-correcting in a sculpted Fresnel annulus defined by said inner and outer diameters.
11. Sculpture apparatus according to claim 3, in which said reflector means includes a transparent plate having a succession of reflecting elements on a surface thereof, said reflecting elements being of progressively changing area, and microprocessor-controlled means for indexing said reflecting elements into successive alignment with the axis of the laser beam.
12. Sculpture apparatus according to claim 9, in which said reflecting elements are in spaced rectilinear array.
13. Sculpture apparatus according to claim 9, in which said reflecting elements are in spaced array about an axis of index rotation.
14. Sculpture apparatus according to claim 3, in which said reflector means is a variable-aperture diaphragm characterized by a reflective side oriented to reflect the laser beam in a peripherally continuous annular area surrounding the instantaneous diaphragm aperture.
15. Sculpture apparatus according to claim 3, in which laser-beam incidence upon said reflector means is at 45 degrees, and in which the reflector area is always elliptical with a major-axis to minor-axis ratio of .sqroot.2:1, the laser-beam incidence being centered on the ellipse and at 45 degrees to the major-axis thereof.
16. Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means producing an output beam in the ultraviolet portion of the electromagnetic spectrum, masking means for variably limiting the area of said beam at impingement on the cornea, said masking means including actuating means for varying the masked area thereof, the range of mask-area variation being within a maximum area to be ablated and being symmetrical with respect to a beam projection axis which coincides with the optical axis of the eye, the intensity of laser-spot projection being limited per unit time to ablate but a fraction of a predetermined maximum ablation into the stroma region of the cornea, said masking means being operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, and characterized by varying inner diameter, said areas being further defined by constant outer diameter for an area within which a hyperopia-correcting curvature change is to be effected; said area of curvature change being less than said maximum area thereby defining an annular area of laser-beam projection outside said area of curvature change, said masking means being further operative within said annular area to provide cornea exposure at a succession of circularly annular areas contiguous to the area of curvature change and of varying outer diameter, and means including a microprocessor with coordinating control connections to said laser means and to said actuating means, whereby laser-beam impingement at the cornea may be so correlated with variation of masked-spot area as to effect a hyperopia-correcting diopter change at the cornea, together with a smoothed surrounding annulus of transition to adjacent unexposed corneal tissue.
17. Sculpture apparatus according to claim 1, in which said control means is further connected to said laser means and to said controllable means, for so correlating laser-beam impingement at the cornea with beam-section veriation in an outer annular area which is contiguous to the curvature-correcting area of diopter change as to effect a graduated radially outward transition (a) from the depth of stroma ablation at the perimeter of diopter change and (b) to substantially zero depth at the outer limit of said annular area.
18. Apparatus for performing ophthalmological surgery by selective ablation of the anterior surface of the cornea of an eye of a patient with penetration into the stroma to achieve a volumetric removal of tissue within the optically functioning area of the cornea, said apparatus comprising laser means producing on an optical axis an output beam in the ultraviolet portion of the electromagnetic spectrum, optical means on said axis including a zoom lens with a zoom drive for variably setting the sectional area of said beam to a spot on the cornea, the area variation of said spot being within a maximum area to be ablated and being symmetrical with respect to a beam-projection axis which coincides with the optical axis of the eye, the intensity of laser-beam projection being limited per unit time to ablate but a fraction of a predetermined maximum ablation into the stroma region of the cornea, and means including a microprocessor with coordinating control connections to said laser means and to said zoom drive, whereby the integrated time of laser-beam impingement at the cornea may be so correlated with variable confined-spot area as to effect a diopter-reducing change at the cornea.
19. Apparatus according to claim 18 or claim 2, in which said zoom lens is of a variety to convert said output beam into a confined circular section of area which varies in accordance with variation in the setting of said zoom drive, whereby the diopter-reducing change may be myopia-correcting.
20. Apparatus according to claim 18 or claim 2, in which said zoom lens is of a variety to convert said output beam into a confined straight line extending diametrically through the optical axis, said line being of width which varies in accordance with variation in the setting of said zoom drive, whereby the diopter-reducing change may be corrective of astigmatism.
21. Apparatus according to claim 18 or claim 2, in which said zoom lens is of a variety to convert said output beam into a confined straight line extending diametrically through the optical axis, said line being of width which varies in accordance with variation in the setting of said zoom drive, whereby the diopter-reducing change may be corrective of astigmatism, and in which said zoom lens has an optical axis and is mounted for selective bodily rotation about its optical axis, whereby the angular orientation of said straight line may be set to accord with that of required astigmatism correction.
22. Apparatus for performing ophthalmological surgery by selective ablation of the anterior surface of the cornea of an eye of a patient with penetration into the stroma to achieve a volumetric removal of tissue within the optically functioning area of the cornea, said apparatus comprising laser means producing on an optical axis an output beam in the ultraviolet portion of the electromagnetic spectrum, masking means for variably limiting the sectional area of said beam at impingement on the cornea, said masking means including actuating means for varying the sectional area masked by said masking means, the mask-area variation being over a range of areas within a maximum area to be ablated and being symmetrical with respect to a beam projection axis which coincides with the optical axis of the eye, the intensity of laser-beam projection being limited per unit time to ablate but a fraction of a predetermined maximum ablation into the stroma of the cornea, and means including a microprocessor with coordinating control connections to said laser means and to said actuating means, whereby laser-beam impingement at the cornea may be so correlated with variation of sectional area as to effect a diopter change at the cornea.
23. Apparatus for performing ophthalmological surgery by selective ablation of the anterior surface of the cornea of an eye of a patient with penetration into the stroma to achieve a volumetric removal of tissue within the optically functioning area of the cornea, said apparatus comprising laser means producing on an optical axis an output beam in the ultraviolet portion of the electromagnetic spectrum, masking means for variably limiting the sectional area of said beam at impingement on the cornea, said masking means including actuating means for varying the sectional area marked by said masking means, the mask-area variation being over a range of areas within a maximum area to be ablated and being symmetrical with respect to a beam projection axis which coincides with the optical axis of the eye, the intensity of laser-beam projection being limited per unit time to ablate but a fraction of a predetermined maximum ablation into the stroma of the cornea, and programmable means with coordinating control connections to said laser means and to said actuating means, whereby laser-beam impingement at the cornea may be so correlated with variation of sectional areas as to effect a diopter change at the cornea.
24. Apparatus according to claim 22 or claim 23, in which said masking means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being elongate rectangular and of varying width, whereby the diopter change may be astigmatism-correcting.
25. Apparatus according to claim 22 or claim 23, in which said masking means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being elongate rectangular and of varying width, whereby the diopter change may be astigmatism-correcting, and wherein orientation of the elongate direction of said areas is variable.
26. Apparatus according to claim 22 or claim 23, in which said masking means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, being defined by a constant outer diameter and by a varying inner diameter, whereby the diopter change may be hyperopia-correcting.
27. Apparatus according to claim 22 or claim 23, in which said masking means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, being defined by a constant inner diameter and by a varying outer diameter which is intermediate said inner diameter and the outer diameter of said maximum area, whereby the diopter change may be myopia-correcting in a sculpted Fresnel annulus defined by said inner and outer diameters.
28. Apparatus according to claim 2 or claim 23, in which said masking means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, being defined by a constant outer diameter and by an inner diameter which varies to a fixed minimum inner diameter, whereby the diopter change may be hyperopia-correcting in a sculpted Fresnel annulus defined by said constant outer diameter and by said fixed minimum inner diameter.
29. Apparatus according to claim 22 or claim 23, in which said masking means includes an opaque plate having a succession of windows which are (a) transparent to laser-beam transmission therethrough and (b) of progressively changing area, and in which said microprocessor-controlled means is connected to index said windows into successive alignment with the axis of the laser beam.
30. Apparatus according to claim 22 or claim 23, in which said masking means includes an opaque plate having a succession of windows which are (a) transparent to laser-beam transmission therethrough and (b) of progressively changing area, and in which said microprocessor-controlled means is connected to index said windows into successive alignment with the axis of the laser beam, and in which said windows are in spaced rectilineal array.
31. Apparatus according to claim 22 or claim 23, in which said masking means includes an opaque plate having a succession of windows which are (a) transparent to laser-beam transmission therethrough and (b) of progressively changing area, and in which said microprocessor-controlled means is connected to index said windows into successive alignment with the axis of the laser beam, and in which said windows are in spaced circular array.
32. Apparatus according to claim 22 or claim 23, in which said masking means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circular, whereby the diopter change may be myopia-correcting.
33. Apparatus according to claim 22 or claim 23, in which said masking means includes an opaque plate having a succession of windows which are (a) transparent to laser-beam transmission therethrough and (b) of progressively changing area, and in which said programmable means is connected to index said windows into successive alignment with the axis of the laser beam.
34. Apparatus according to claim 22 or claim 23, in which said masking means includes an opaque plate having a succession of windows which are (a) transparent to laser-beam transmission therethrough and (b) of progressively changing area, and in which said programmable means is connected to index said windows into successive alignment with the axis of the laser beam, and in which said windows are in spaced rectilineal array.
35. Apparatus according to claim 22 or claim 23, in which said masking means includes an opaque plate having a succession of windows which are (a) transparent to laser-beam transmission therethrough and (b) of progressively changing area, and in which said programmable means is connected to index said windows into successive alignment with the axis of the laser beam, and in which said windows are in spaced circular array.
36. Apparatus for performing ophthalmological surgery by selective ablation of the anterior surface of the cornea of an eye of a patient with penetration into the stroma to achieve a volumetric removal of tissue within the optically functioning area of the cornea, said apparatus comprising laser means producing on an optical axis an output beam in the ultraviolet portion of the electromagnetic spectrum, optical means including reflector means for reflecting said beam on said axis and for variably limiting the sectional area of said beam at impingement on the cornea, said reflector means including actuating means for varying the reflecting area thereof, the reflecting-area variation being over a range producing reflected-beam section areas within a maximum area to be ablated and being symmetrical with respect to a beam-projection axis adapted for alignment with the optical axis of the eye, the intensity of the projected beam being limited per unit time to ablate but a fraction of a predetermined maximum ablation into the stroma of the cornea, and means including a microprocessor with coordinating control connections to said laser means and to said actuating means, whereby laser-beam impingement at the cornea may be so correlated with variation of reflected-beam section areas as to effect a diopter change at the cornea.
37. Apparatus according to claim 36, in which laser-beam incidence upon said reflector means is at 45 degrees, and in which the reflecting area is always elliptical with a major-axis to minor-axis ratio of .sqroot.2:1, the laser-beam incidence being centered on the ellipse and at 45 degrees to the major-axis thereof.
38. Apparatus for performing ophthalmological surgery by selective ablation of the anterior surface of the cornea of an eye of a patient with penetration into the stroma to achieve a volumetric removal of tissue within the optically functioning area of the cornea, said apparatus comprising laser means producing on an optical axis an output beam in the ultraviolet portion of the electromagnetic spectrum, optical means including reflector means for reflecting said beam on said axis and for variably limiting the sectional area of said beam at impingement on the cornea, said reflector means including actuating means for varying the reflecting area thereof, the reflecting-area variation being over a range producing reflected-beam section areas within a maximum area to be ablated and being symmetrical with respect to a beam-projection axis adapted for alignment with the optical axis of the eye, the intensity of the projected beam being limited per unit time to ablate but a fraction of a predetermined maximum ablation into the stroma of the cornea, and programmable means with coordinating control connections to said laser means and to said actuating means, whereby laser-beam impingement at the cornea may be so correlated with variation of reflected-beam section area as to effect a diopter change at the cornea.
39. Apparatus according to claim 36 or claim 38, in which said reflector means is operative to provide cornea exposure at a narrow elongate rectangular area centered on the optical axis of the projected beam and spanning said maximum area, said reflector means being further operative to provide cornea exposure at a plurality of similarly shaped but greater areas, said areas being elongate rectangular and of varying width which is symmetrical about the elongate direction of said narrow area, whereby the diopter change may be astigmatism-correcting.
40. Apparatus according to claim 36 or claim 38, in which said reflector means is operative to provide cornea exposure at a narrow elongate rectangular area centered on the optical axis of the projected beam and spanning said maximum area, said reflector means being further operative to provide cornea exposure at a plurality of similarly shaped but greater areas, said areas being elongate rectangular and of varying width which is symmetrical about the elongate direction of said narrow area, whereby the diopter change may be astigmatism-correcting, and wherein orientation of the elongate direction of said areas is variable.
41. Apparatus according to claim 36 or claim 38, in which said reflector means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, being defined by a constant outer diameter and by an inner diameter which varies to a fixed minimum inner diameter, whereby the diopter change may be hyperopia-correcting in a sculpted Fresnel annulus defined by said constant outer diameter and by said fixed minimum inner diameter.
42. Apparatus according to claim 36 or claim 38, in which said reflector means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being circularly annular, being defined by a constant inner diameter and by a varying outer diameter which is intermediate said inner diameter and the outer diameter of said maximum area, whereby the diopter change may be myopia-correcting in a sculpted Fresnel annulus defined by said inner and outer diameters.
43. Apparatus according to claim 36 or claim 38, in which said reflector means includes a transparent plate having a succession of reflecting elements on a surface thereof, said reflecting elements being of progressively changing area, and in which said microprocessor-controlled means is connected to index said reflecting elements into successive alignment with the axis of the laser beam.
44. Apparatus according to claim 36 or claim 38, in which said reflector means includes a transparent plate having a succession of reflecting elements on a surface thereof, said reflecting elements being of progressively changing area, and in which said microprocessor-controlled means is connected to index said reflecting elements into successive alignment with the axis of the laser beam, and in which said reflecting elements are in spaced rectilineal array.
45. Apparatus according to claim 36 or claim 38, in which said reflector means includes a transparent plate having a succession of reflecting elements on a surface thereof, said reflecting elements being of progressively changing area, and in which said microprocessor-controlled means is connected to index said reflecting elements into successive alignment with the axis of the laser beam, and in which said reflecting elements are in spaced array about an axis of index rotation.
46. Apparatus according to claim 36 or claim 38, in which said reflector means is a variable-aperture diaphragm characterized by a reflective side oriented to reflect the laser beam in a peripherally continuous annular area surrounding the diaphragm aperture.
47. Apparatus according to claim 36 or claim 38, in which said reflector means is operative to provide cornea exposure at a central circular area and at a plurality of similarly shaped but greater areas, said areas being concentric, whereby the diopter change may be myopia-correcting.
48. Apparatus according to claim 36 or claim 38, in which said reflector means is operative to provide cornea exposure at said maximum area and at a plurality of similarly shaped but lesser areas, said areas being annular and characterized by varying inner radius within said maximum area, whereby the diopter change may be hyperopia-correcting.