EP0218427A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for ophthalmological surgery
Assignee: AMO Manufacturing USA LLC
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Filing: 1986-09-26
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Granted: —
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Expires: 2006-09-26
Abstract
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 precharacterized distribution of flus density across the cross-section of laser-beam projection, in the context of beam size, at cornea incidence, to match the area to be ablated, and the duration of exposure determines the extent of curvature change. Illustrative techniques and situations are disclosed, for myopia correction, for hyperopia correction, and for astigmatism correction.
Inventors
- 👤 Francis A. L'Espérance
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 11:01
CPC Classifications
A; A61; A61F; A61F9/00; A61F9/007; A61F9/008; A61F9/00802; A61F9/00804; A61B; A61B17/00; A61B17/30; A61B2017/306; A61B18/00; A61B18/18; A61B18/20; A61B2018/2035; A61B2018/20351; A61B2018/20353; A61B2018/20355; A61F2009/00861; A61F2009/00872; A61F9/00817; A61F9/00819; A61F9/009
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
123 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing an output beam in the ultraviolet portion of the electromagnetic spec- turm, said output beam having a central axis, precharacterizing means positioned in said beam for transmitting only a precharacterized radiation beam to the cornea, the precharacterization being such that in the precharacterized beam transmitted to the cornea flux-density distribution is a circumferentially uniform decreasing or increasing function of radius about the central axis of said precharacterized beam, whereby when the axis of said prechatacterized beam is aligned with the axis of an eye, a myopia-correcting or hyperopia-correcting curvature change respectively may be effected in the anterior surface of the cornea.
Claim 2
Dependent Claim
123 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing an output beam in the ultraviolet portion of the electromagnetic spec- turm, said output beam having a central axis, precharacterizing means positioned in said beam for transmitting only a precharacterized radiation beam to the cornea, the precharacterization being such that in the precharacterized beam transmitted to the cornea flux-density distribution is a circumferentially uniform decreasing or increasing function of radius about the central axis of said precharacterized beam, whereby when the axis of said prechatacterized beam is aligned with the axis of an eye, a myopia-correcting or hyperopia-correcting curvature change respectively may be effected in the anterior surface of the cornea.
Claim 3
Dependent Claim
156 words
Sculpture apparatus according to claim 1 in which said laser means produces a circular beam of cross-section sized for equality with the projected area of the cornea to be operated upon, said circular cross-section being precharacterized (a) by an inner circle of diameter which is but a fraction of the diameter of said cross-section and (b) by at least one circular annulus which is radially contiguous to said inner circle, the said precharacterization of said precharacterizing means being that of said inner circle, said circular cross-section being precharacterized further in the circular annulus thereof such that flux-density distribution is also a circumferentially uniform function of radius and in the same sense and between substantially the same density limits as apply to said inner circle, whereby a Fresnel-type corneal-curvature correction may be obtained in both said inner circle and in said circular annulus in the course of a single laser-beam exposure to the cornea of the eye.
Claim 4
Dependent Claim
162 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing an output beam in the ultraviolet portion of the electromagnetic spectrum, said output beam having a central axis, precharacterizing means positioned in said beam for transmitting only a precharacterized radiation beam to the cornea, the precharacterization being such that in the precharacterized beam transmitted to the cornea, flux-density distribution is symmetrical about a single diametral alignment through the center of said beam, said distribution being such that flux density reduces or increases continuously and with symmetry on opposite lateral sides and outwardly of said diametral alignment, and means mounting said precharacterizing means for selective rotation about the central axis of the precharacterized beam transmitted to the cornea, whereby for a rotary adjustment of said precharacterizing means to a prescription axis for astigmatism correction, exposure of a cornea aligned with said precharacterized beam will result in ablative reduction of the astigmatism.
Claim 5
Dependent Claim
162 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing an output beam in the ultraviolet portion of the electromagnetic spectrum, said output beam having a central axis, precharacterizing means positioned in said beam for transmitting only a precharacterized radiation beam to the cornea, the precharacterization being such that in the precharacterized beam transmitted to the cornea, flux-density distribution is symmetrical about a single diametral alignment through the center of said beam, said distribution being such that flux density reduces or increases continuously and with symmetry on opposite lateral sides and outwardly of said diametral alignment, and means mounting said precharacterizing means for selective rotation about the central axis of the precharacterized beam transmitted to the cornea, whereby for a rotary adjustment of said precharacterizing means to a prescription axis for astigmatism correction, exposure of a cornea aligned with said precharacterized beam will result in ablative reduction of the astigmatism.
Claim 6
Dependent Claim
17 words
Sculpture apparatus according to any preceding claim in which said precharacterizing means is a thin-film gradient filter.
Claim 7
Dependent Claim
34 words
Sculpture apparatus according to claim 4 in which said thin-film gradient filter comprises a substrate transparent to the laser-radiation wavelength and having a photo-deposited half-tone coating wherein the precharacterization is in the half-tone coating.
Claim 8
Dependent Claim
42 words
Sculpture apparatus according to claim 4 in which said thin-film gradient filter comprises a substrate somewhat opaque to the laser-radiation wavelength, said substrate having a distributed plurality of microporous apertures therein, the density distribution of said apertures according with said flux-density distribution.
Claim 9
Dependent Claim
18 words
Sculpture apparatus according to claim 4 in which said thin-film gradient filter comprises a reflector having precharacterized reflectance.
Claim 10
Dependent Claim
72 words
Sculpture apparatus according to claim 3 or any claim dependent thereon, in which in the opposed directions laterally outward of said single diametral alignment, said flux-density distribution (i) is a uniformly increasing function of lateral offset from said alignment to a maximum flux-density at first opposed lateral-offset limits of astigmatism-correcting sculpture, and (ii) is a uniformly decreasing function of lateral offset, from said maximum laterally outward of said first opposed lateral-offset limits.
Claim 11
Dependent Claim
196 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing a circular output beam in the ultraviolet portion of the electromagnetic spectrum, means including a precharacterized beam splitter positioned in said beam for dividing laser radiation into a reflected-component beam and into a transmitted component beam, the precharacterization of said beam-splitter being (a) such that in one of said component beams flux-density distribution is a circumferentially uniform increasing function of radius about the central axis of said one component beam and (b) such that in the other of said component beams flux-density distribution is a circumferentially uniform decreasing function of radius about the central axis of said other component beam; whereby, when the axis of said one component beam is aligned with the axis of a myopic eye, a myopia-correcting curvature change may be effected in the anterior surface of the cornea of the myopic eye; and further whereby, when the axis of said other component beam is aligned with the axis of a hyperopic eye, a hyperopia-correcting curvature change may be effected in the anterior surface of the cornea of the hyperopic eye.
Claim 12
Dependent Claim
196 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing a circular output beam in the ultraviolet portion of the electromagnetic spectrum, means including a precharacterized beam splitter positioned in said beam for dividing laser radiation into a reflected-component beam and into a transmitted component beam, the precharacterization of said beam-splitter being (a) such that in one of said component beams flux-density distribution is a circumferentially uniform increasing function of radius about the central axis of said one component beam and (b) such that in the other of said component beams flux-density distribution is a circumferentially uniform decreasing function of radius about the central axis of said other component beam; whereby, when the axis of said one component beam is aligned with the axis of a myopic eye, a myopia-correcting curvature change may be effected in the anterior surface of the cornea of the myopic eye; and further whereby, when the axis of said other component beam is aligned with the axis of a hyperopic eye, a hyperopia-correcting curvature change may be effected in the anterior surface of the cornea of the hyperopic eye.
Claim 13
Dependent Claim
126 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing a circular output beam in the ultraviolet portion of the electromagnetic spectrum, means including a precharacterized beam splitter positioned in said beam for dividing laser radiation into a reflected-component beam and into a transmitted component beam, the precharacterization of said beam-splitter being such that in the reflected-component beam or the transmitted component beam flux-density distribution is a circumferentially uniform decreasing or increasing function of radius about the central axis of said beam, whereby when the axis of said beam is aligned with the axis of an eye, a myopia-correcting or hyperopia-correcting curvature change respectively may be effected in the anterior surface of the cornea.
Claim 14
Dependent Claim
126 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing a circular output beam in the ultraviolet portion of the electromagnetic spectrum, means including a precharacterized beam splitter positioned in said beam for dividing laser radiation into a reflected-component beam and into a transmitted component beam, the precharacterization of said beam-splitter being such that in the reflected-component beam or the transmitted component beam flux-density distribution is a circumferentially uniform decreasing or increasing function of radius about the central axis of said beam, whereby when the axis of said beam is aligned with the axis of an eye, a myopia-correcting or hyperopia-correcting curvature change respectively may be effected in the anterior surface of the cornea.
Claim 15
Dependent Claim
23 words
Sculpture apparatus according to claim 10 wherein energy-absorbing means is positioned in the path of the transmitted-component beam, or the reflected-component beam respectively.
Claim 16
Dependent Claim
158 words
Sculpture apparatus according to claim 10 or 11, in which said laser means produces a circular beam of cross-section sized for equality with the projected area of the cornea to be operated upon, said circular cross-section being precharacterized (a) by an inner circle of diameter which is but a fraction of the diameter of said cross-section and (b) by at least one circular annulus which is radially contiguous to said inner circle, the said precharacterization of said beam splitter being that of said inner circle, said circular cross-section being precharacterized further in the circular annulus thereof such that flux-density distribution is also a circumferentially uniform function of radius and in the same sense and between substantially the same density limits as apply to said inner circle, whereby a Fresnel-type corneal-curvature correction may be obtained in both said inner circle and in said circular annulus in the course of a single laser-beam exposure to the cornea of the eye.
Claim 17
Dependent Claim
153 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing a circular output beam in the ultraviolet portion of the electromagnetic spectrum, means including a precharacterized beam splitter positioned in said beam for dividing laser radiation into a reflected-component beam and into a transmitted component beam, the precharacterization of said beam-splitter being such that in the transmitted-component beam flux-density distribution is symmetrical about a single diametral alignment through the center of said beam, said distribution being such that flux density reduces continuously and with symmetry on opposite lateral sides of said diametral alignment, and means mounting said beam-splitter for selective rotation about the central axis of the transmitted-component beam, whereby for a rotary adjustment of said beam-splitter to a prescription axis for astigmatism correction, exposure of a cornea aligned with said transmitted-component beam will result in ablative reduction of the astigmatism.
Claim 18
Dependent Claim
153 words
Sculpture apparatus for operation upon the external surface of the cornea of an eye of a patient, comprising laser means for producing a circular output beam in the ultraviolet portion of the electromagnetic spectrum, means including a precharacterized beam splitter positioned in said beam for dividing laser radiation into a reflected-component beam and into a transmitted component beam, the precharacterization of said beam-splitter being such that in the transmitted-component beam flux-density distribution is symmetrical about a single diametral alignment through the center of said beam, said distribution being such that flux density reduces continuously and with symmetry on opposite lateral sides of said diametral alignment, and means mounting said beam-splitter for selective rotation about the central axis of the transmitted-component beam, whereby for a rotary adjustment of said beam-splitter to a prescription axis for astigmatism correction, exposure of a cornea aligned with said transmitted-component beam will result in ablative reduction of the astigmatism.
Claim 19
Dependent Claim
76 words
Sculpture apparatus according to any of claims 9 to 14 in which said beam-splitter is centered on a circular plate, and in which an eye-contacting mount is adapted to support said plate in slightly tilted position wherein the central geometric normal to the plate is at small angular offset from the central axis of the eye or is adapted to support said plate with its center on the alignment of the central axis of the eye.
Claim 20
Dependent Claim
68 words
Sculpture apparatus according to claim 1 or claim 10 or any claim dependent thereon in which said flux-density distribution (i) is a circumferentially uniform increasing function of radius out to a maximum flux density at a first radial limit of hyperopia-corrected area, and (ii) is a circumferentially uniform decreasing function of radius, from said maximum and out to a minimum at a second radial limit of laser-beam cross-section.
Claim 21
Independent Claim
221 words
The method of using an ultraviolet laser beam to effect a curvature change in the anterior surface of a cornea and thereby to change optical properties of an eye by selectively ablating the anterior surface with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover a predetermined anterior-surface area of optical correction, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma; subjecting the laser beam to precharacterized attenuation which is a circumferentially uniform function of radius about the central axis of the laser beam, the precharacterization varying in a single direction for the radial extent of the predetermined area of optical correction, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth for the region of least precharacterized attenuation.
Claim 22
Independent Claim
221 words
The method of using an ultraviolet laser beam to effect a curvature change in the anterior surface of a cornea and thereby to change optical properties of an eye by selectively ablating the anterior surface with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover a predetermined anterior-surface area of optical correction, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma; subjecting the laser beam to precharacterized attenuation which is a circumferentially uniform function of radius about the central axis of the laser beam, the precharacterization varying in a single direction for the radial extent of the predetermined area of optical correction, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth for the region of least precharacterized attenuation.
Claim 23
Independent Claim
210 words
The method of using an ultraviolet laser beam to effect a myopia-correcting change in optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover a predetermined area of myopia-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the strom, characterizing the radial distribution of flux-density about the sectional center of laser-beam projection such that the maximum flux density is at the center and minimum flux density is at the maximum dameter of the area of myopia-correcting change, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the optical center of the eye.
Claim 24
Independent Claim
210 words
The method of using an ultraviolet laser beam to effect a myopia-correcting change in optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover a predetermined area of myopia-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the strom, characterizing the radial distribution of flux-density about the sectional center of laser-beam projection such that the maximum flux density is at the center and minimum flux density is at the maximum dameter of the area of myopia-correcting change, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the optical center of the eye.
Claim 25
Independent Claim
205 words
The method of using an ultraviolet laser beam to effect a hyperopia-correcting change in optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover a predetermined area of hyperopia-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing the radial distribution of flux density about the sectional center of laser-beam projection such that maximum flux density is at the maximum diameter of the area of hyperopia-correcting change, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the maximum diameter of said area of hyperopia-correcting change.
Claim 26
Independent Claim
205 words
The method of using an ultraviolet laser beam to effect a hyperopia-correcting change in optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover a predetermined area of hyperopia-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing the radial distribution of flux density about the sectional center of laser-beam projection such that maximum flux density is at the maximum diameter of the area of hyperopia-correcting change, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the maximum diameter of said area of hyperopia-correcting change.
Claim 27
Independent Claim
287 words
The method of using an ultraviolet laser beam to change optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a maximum-area circular spot which is centered on and equal to the area of the cornea to be subjected to ablation, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing the radial distribution of flux-density about the sectional center of laser-beam projection, such that said circular spot is characterized (a) by an inner circle of diameter which is but a fraction of the diameter of said circular spot and (b) by at least one circular annulus which is radially contiguous to said inner circle, said flux-density distribution being over a first range for which maximum is at the center and for which minimum is at the outer diameter of said inner circle, said flux-density distribution being also over a second range for which maximum is radially contiguous to the outer diameter of said inner circle and for which minimum is at the outer diameter of said circular annulus, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the optical center of the eye, whereby a myopia-correcting Fresnel-type correcting change in the anterior surface may be effected by volumetric removal of corneal tissue.
Claim 28
Independent Claim
287 words
The method of using an ultraviolet laser beam to change optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a maximum-area circular spot which is centered on and equal to the area of the cornea to be subjected to ablation, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing the radial distribution of flux-density about the sectional center of laser-beam projection, such that said circular spot is characterized (a) by an inner circle of diameter which is but a fraction of the diameter of said circular spot and (b) by at least one circular annulus which is radially contiguous to said inner circle, said flux-density distribution being over a first range for which maximum is at the center and for which minimum is at the outer diameter of said inner circle, said flux-density distribution being also over a second range for which maximum is radially contiguous to the outer diameter of said inner circle and for which minimum is at the outer diameter of said circular annulus, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the optical center of the eye, whereby a myopia-correcting Fresnel-type correcting change in the anterior surface may be effected by volumetric removal of corneal tissue.
Claim 29
Independent Claim
288 words
The method of using an ultraviolet laser beam to change optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a maximum-area circular spot which is centered on and equal to the area of the cornea to be subjected to ablation, adjusting the intensity of laser beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma characterizing the radial distribution of flux-density about the sectional center of laser-beam projection, such that said circular spot is characterized (a) by an inner circle of diameter which is but a fraction of the diameter of said circular spot and (b) by at least one circular annulus which is radially contiguous to said inner circle, said flux-density distribution being over a first range for which minimum is at the center and for which maximum is at the outer diameter of said inner circle, said flux-density distribution being also over a second range for which minimum is radially contiguous to the outer diameter of said inner circle and for which maximum is at the outer diameter of said circular annulus, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the maximum diameter of said inner circle, whereby a hyperopia-correcting Fresnel-type correcting change in the anterior surface may be effected by volumetric removal of corneal-tissue.
Claim 30
Independent Claim
288 words
The method of using an ultraviolet laser beam to change optical properties of an eye by selectively ablating the anterior surface of the cornea with penetration into the stroma to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a maximum-area circular spot which is centered on and equal to the area of the cornea to be subjected to ablation, adjusting the intensity of laser beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma characterizing the radial distribution of flux-density about the sectional center of laser-beam projection, such that said circular spot is characterized (a) by an inner circle of diameter which is but a fraction of the diameter of said circular spot and (b) by at least one circular annulus which is radially contiguous to said inner circle, said flux-density distribution being over a first range for which minimum is at the center and for which maximum is at the outer diameter of said inner circle, said flux-density distribution being also over a second range for which minimum is radially contiguous to the outer diameter of said inner circle and for which maximum is at the outer diameter of said circular annulus, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at the maximum diameter of said inner circle, whereby a hyperopia-correcting Fresnel-type correcting change in the anterior surface may be effected by volumetric removal of corneal-tissue.
Claim 31
Independent Claim
220 words
The method of using an ultraviolet laser beam to change optical properties of an astigmatic eye by selectively ablating the anterior surface of the cornea with penetration into the stroma region to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover an area of astigmatism-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing flux-density distribution within said circular spot such that maximum flux density is (a) on a diametral alignment through the center of the circular spot and (b) at a prescribed angular orientation about said center and (c) such that the flux-density reduces continuously and with symmetry on opposite lateral sides of said diametral alignment, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth along said diametral alignment.
Claim 32
Independent Claim
220 words
The method of using an ultraviolet laser beam to change optical properties of an astigmatic eye by selectively ablating the anterior surface of the cornea with penetration into the stroma region to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover an area of astigmatism-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing flux-density distribution within said circular spot such that maximum flux density is (a) on a diametral alignment through the center of the circular spot and (b) at a prescribed angular orientation about said center and (c) such that the flux-density reduces continuously and with symmetry on opposite lateral sides of said diametral alignment, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth along said diametral alignment.
Claim 33
Independent Claim
228 words
The method of using an ultraviolet laser beam to change optical properties of an astigmatic eye by selectively ablating the anterior surface of the cornea with penetration into the stroma region to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover an area between opposed outer limits of astigmatism-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing flux-density distribution within said circular spot such that minimum flux density is (a) on a diametral alignment through the center of the circular spot and (b) at a prescribed angular orientation about said center and (c) such that the flux-density increases continuously and with symmetry on opposite lateral sides of said diametral alignment, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at said opposite lateral limits of astigmatism-correcting change.
Claim 34
Independent Claim
228 words
The method of using an ultraviolet laser beam to change optical properties of an astigmatic eye by selectively ablating the anterior surface of the cornea with penetration into the stroma region to achieve a volumetric removal of corneal tissue, which method comprises confining the laser beam to a circular spot which is centered on and equal at least to the area of the cornea to be subjected to ablation, whereby said beam is of sectional area at least sufficient to cover an area between opposed outer limits of astigmatism-correcting change, adjusting the intensity of laser-beam projection to a limited level at which resultant corneal-tissue ablation per unit time is to an ascertained elemental depth which is but a fraction of a predetermined maximum ablation depth into the stroma, characterizing flux-density distribution within said circular spot such that minimum flux density is (a) on a diametral alignment through the center of the circular spot and (b) at a prescribed angular orientation about said center and (c) such that the flux-density increases continuously and with symmetry on opposite lateral sides of said diametral alignment, and directing the adjusted and characterized beam to the anterior surface with said spot centered on the optical axis of the eye for that period of time which will accomplish ablative penetration to the predetermined maximum ablation depth at said opposite lateral limits of astigmatism-correcting change.
Claim 35
Independent Claim
137 words
The method of effecting an optically correcting change within a predetermined area of the anterior surface of the cornea of an eye, from an initial curvature requiring myopia or hyperopia correction to a subsequent curvature having improved optical properties, which method comprises using ultraviolet laser radiation in a program of selective ablation of the anterior surface of the cornea by photodecomposition, with penetration into the stroma and volumetric sculpturing removal of corneal tissue to such penetration depth and profile as to characterize the anterior surface with said subsequent curvature, said sculpturing removal being via laser radiation which is characterized by a circular spot wherein flux density respectively decreases or increases radially outward at least to the perimeter of said predetermined area, and said program being for a time predetermined to achieve a desired myopia-correcting or hyperopia-correcting change.
Claim 36
Independent Claim
137 words
The method of effecting an optically correcting change within a predetermined area of the anterior surface of the cornea of an eye, from an initial curvature requiring myopia or hyperopia correction to a subsequent curvature having improved optical properties, which method comprises using ultraviolet laser radiation in a program of selective ablation of the anterior surface of the cornea by photodecomposition, with penetration into the stroma and volumetric sculpturing removal of corneal tissue to such penetration depth and profile as to characterize the anterior surface with said subsequent curvature, said sculpturing removal being via laser radiation which is characterized by a circular spot wherein flux density respectively decreases or increases radially outward at least to the perimeter of said predetermined area, and said program being for a time predetermined to achieve a desired myopia-correcting or hyperopia-correcting change.
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