EP0274205A2 — Sculpture apparatus for correcting curvature of t…

Claim 1

Independent Claim 188 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which termines with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predetermined exposure time to so distribute the cumulative depth of ablation as to achieve a new and improved corneal curvature, the improvement in which computer means includes a digital storage of the beam-section distribution of flux-density data that is predetermined to effect a selected curvature correction, and in which beam-monitoring means associated with said computer means includes a beam-sampling splitter positioned in said optical path after characterization of flux-density distribution, said beam-monitoring means being electrically responsive to beam-section distribution of flux density in the sampling beam and producing a digital output indicative of such distribution, said computer means providing a comparative indication of the monitored distribution in relation to the digitally stored distribution data.

Claim 2

Dependent Claim 188 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which termines with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predetermined exposure time to so distribute the cumulative depth of ablation as to achieve a new and improved corneal curvature, the improvement in which computer means includes a digital storage of the beam-section distribution of flux-density data that is predetermined to effect a selected curvature correction, and in which beam-monitoring means associated with said computer means includes a beam-sampling splitter positioned in said optical path after characterization of flux-density distribution, said beam-monitoring means being electrically responsive to beam-section distribution of flux density in the sampling beam and producing a digital output indicative of such distribution, said computer means providing a comparative indication of the monitored distribution in relation to the digitally stored distribution data.

Claim 3

Dependent Claim 69 words

The improved apparatus of claim 1, in which shutter means on said path and in downstream proximity to said splitter is normally closed to foreclose delivery of laser radiation to the eye, said shutter means having an actuating connection from said monitoring means and being actuable to open condition only in the event that the monitored distribution data and the digitally stored distribution data conform within predetermined tolerance limits.

Claim 4

Dependent Claim 37 words

The improved apparatus of claim 1, in which said beam-monitoring means includes a second beam-sampling splitter positioned in said path prior to characterization of flux-density distribution, whereby homogeneity of the beam may be monitored prior to beam-characterizing.

Claim 5

Dependent Claim 114 words

The apparatus of claim 1, (a) in which the characterizing of flux-density distribution is a function of radius about the cornea-impingement axis, (b) in which said computer means includes a digital storage of data to effect flux-density distribution that is predetermined to effect a selected spherical curvature correction, and (c) in which said beam-monitoring means includes a further beam-sampling splitter positioned in said optical path after characterization of flux-density distribution, said beam-monitoring means being electrically responsive to distribution of flux density in the further sampling beam and producing a digital output indicative of such distribution, said computer means providing a comparative indication of the characterized distribution in relation to digitally stored flux-density distribution data.

Claim 6

Dependent Claim 137 words

The apparatus of claim 1, (a) in which the characterizing of flux-density distribution is a symmetrical function on laterally opposed sides of a diametrically extending axis intersecting the cornea-impingement axis and at an angular orientation consistent with the axis of an astigmatism to be reduced, (b) in which said computer means includes a digital storage of flux-density data that is predetermined to effect a selected cylindrical curvature correction consistent with said orientation, and (c) in which said beam-monitoring means includes a further beam-sampling splitter positioned in said optical path after characterization of flux-density distribution, said beam-monitoring means being electrically responsive to distribution of flux density in the further sampling beam and producing a digital output indicative of such distribution, said computer means providing a comparative indication of the characterized distribution in relation to digitally stored flux-density distribution.

Claim 7

Dependent Claim 20 words

The apparatus of claim 5, and additionally including beam-rotating means positioned in said optical path after characterization of flux-density distribution.

Claim 8

Dependent Claim 19 words

The apparatus of claim 6, in which said beam-rotating means is upstream with respect to said further beam-sampling splitter.

Claim 9

Dependent Claim 185 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which terminates with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predetermined exposure time to so distribute the cumulative depth of ablation to achieve a new and improved corneal curvature, the improvement in which computer means includes digitally stored tolerance data reflecting a predetermined level of uniformly distributed laser-beam flux density prior to characterization of flux-density distribution, and in which beam-monitoring means associated with said computer means includes a beam-sampling splitter positioned in said path prior to characterization of flux-density distribution, said beam-monitoring means being electrically responsive to flux distribution in the sampling beam and producing a digital output indicative of such distribution, said computer means providing a comparative indication of the monitored distribution in relation to the digitally stored tolerance data.

Claim 10

Dependent Claim 185 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which terminates with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predetermined exposure time to so distribute the cumulative depth of ablation to achieve a new and improved corneal curvature, the improvement in which computer means includes digitally stored tolerance data reflecting a predetermined level of uniformly distributed laser-beam flux density prior to characterization of flux-density distribution, and in which beam-monitoring means associated with said computer means includes a beam-sampling splitter positioned in said path prior to characterization of flux-density distribution, said beam-monitoring means being electrically responsive to flux distribution in the sampling beam and producing a digital output indicative of such distribution, said computer means providing a comparative indication of the monitored distribution in relation to the digitally stored tolerance data.

Claim 11

Dependent Claim 62 words

The apparatus of claim 8, in which shutter means on said path and downstream from said splitter is normally closed to foreclose delivery of laser radiation to the eye, said shutter means having an actuating connection from said computer means and being actuable to open condition only in the event that the monitored distribution data conforms with the digitally stored tolerance data.

Claim 12

Dependent Claim 207 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which terminates with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predetermined exposure time so as to distribute the cumulative depth of ablation as to achieve a new and improved corneal curvature, the improvement wherein the laser is an excimer laser and wherein beam-homogenizing means is on said path downstream from the laser and upstream with respect to the characterizing of flux distribution, said beam-homogenizing means comprising scraper means limiting beam margins to a rectangular section (a) which is elongate in the width dimension and which is of substantially uniform intensity profile along the width dimension and (b) which is relatively narrow in the height dimension and which is within a substantially 2:1 range of profile variation along the height dimension of the section, and anamorphic beam-expansion means oriented to expand the relatively narrow height dimension of the beam to substantially said width dimension.

Claim 13

Dependent Claim 207 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which terminates with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predetermined exposure time so as to distribute the cumulative depth of ablation as to achieve a new and improved corneal curvature, the improvement wherein the laser is an excimer laser and wherein beam-homogenizing means is on said path downstream from the laser and upstream with respect to the characterizing of flux distribution, said beam-homogenizing means comprising scraper means limiting beam margins to a rectangular section (a) which is elongate in the width dimension and which is of substantially uniform intensity profile along the width dimension and (b) which is relatively narrow in the height dimension and which is within a substantially 2:1 range of profile variation along the height dimension of the section, and anamorphic beam-expansion means oriented to expand the relatively narrow height dimension of the beam to substantially said width dimension.

Claim 14

Dependent Claim 192 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which terminates with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predtermined exposure time to so distribute the cumulative depth of ablation as to achieve a new and improved corneal curvature, the improvement in which the laser is an excimer laser producing an output beam of generally rectangular section wherein flux distribution is generally uniform along the width dimension and is characterized by generally Gaussian distribution along the height dimension, beam-processing means including one or more optical elements on said path, said one or more optical elements being operative (a) substantially only along the height dimension of the beam section and to establish less than a 2:1 range of intensity-profile variation along the height dimension and (b) to expand the height dimension for substantial equality with the width dimension.

Claim 15

Dependent Claim 192 words

In apparatus using an ultraviolet laser to correct an optically deficient eye by volumetric ablative removal of corneal tissue from the anterior surface and with penetration of the stroma, wherein laser-beam delivery is on an optical path which terminates with a fixed cornea-impingement axis aligned with the axis of the eye, and wherein flux distribution is so characterized within a predetermined circle of laser-radiation exposure to the cornea as in the course of a predtermined exposure time to so distribute the cumulative depth of ablation as to achieve a new and improved corneal curvature, the improvement in which the laser is an excimer laser producing an output beam of generally rectangular section wherein flux distribution is generally uniform along the width dimension and is characterized by generally Gaussian distribution along the height dimension, beam-processing means including one or more optical elements on said path, said one or more optical elements being operative (a) substantially only along the height dimension of the beam section and to establish less than a 2:1 range of intensity-profile variation along the height dimension and (b) to expand the height dimension for substantial equality with the width dimension.

Claim 16

Dependent Claim 30 words

The improved apparatus of claim 11, in which said one or more elements include anamorphic beam-expansion means oriented to expand the height dimension to substantial equality with the width dimension.

Claim 17

Dependent Claim 117 words

The improved apparatus of claim 11, in which said one or more elements include first and second plane reflectors positioned with respect to each other and to the height dimension of the beam to laterally oppositely deflect outer one-third fractions of the height dimension of the beam with respect to the remaining central one-third fraction, first holding means including a first beam splitter spanning said central one-third fraction and combining one of said outer fractions with said central fraction, and second folding means including a second beam splitter spanning said central one-third fraction and downstream from said first beam splitter and combining the other of said outer fractions with the beam combined by said first beam splitter.

Claim 18

Dependent Claim 22 words

The apparatus of claim 11, in which said beam-processing means includes scraper means limiting the beam to a circular section following beam-expansion.

Claim 19

Dependent Claim 21 words

The improved apparatus of claim 11, in which said beam-processing means includes selectively operable beam-rotating means downstream with respect to beam-expansion.

Claim 20

Dependent Claim 16 words

The improved apparatus of claim 8, in which said beam-processing means includes spatial-filter means followed beam-expansion.

Claim 21

Dependent Claim 55 words

The improved apparatus in claim 11, in which the height and width dimensions of the expanded beam are substantially greater than the beam-section dimensions at delivery to the eye, means for characterizing the flux distribution on the scale of said greater dimensions, and beam-condenser means operative to reduce the characterized beam to said predetermined circle.

Claim 22

Dependent Claim 15 words

The improved apparatus of claim 17, in which said beam-condenser means is a zoom device.

Claim 23

Dependent Claim 43 words

The improved apparatus of claim 11, in which a multiple-station turret mounts a plurality of different flux-distribution filters at each of a succession of stations that are individually and selectively indexible into said path following beam-expansion, and a beam-condenser downstream from said turret.

Claim 24

Dependent Claim 46 words

The improved apparatus of claim 11, in which an indexible turret is characterized by a successive plurality of openings at predetermined angular spacing, said openings being characterized by progressively changing beam-scraping radius about said path when each opening is indexed into position centered on said path.

Claim 25

Dependent Claim 99 words

Ultraviolet laser-beam section-monitoring apparatus, comprising a beam splitter for sampling at relatively low level the entire section of a laser beam, video camera means sensitive to ultraviolet radiation in a samples beam picked off by said splitter, a TV-display of relative intensity of the sampled beam, a video-recorder connected to store one or more frames of the TV display, a horizontal-line grabber connected to the video recorder to segregate a given line of the frame, and an oscilloscope-display device connected to the output of the line grabber to provide an intensity-profile display for the given line of the frame.

Claim 26

Dependent Claim 99 words

Ultraviolet laser-beam section-monitoring apparatus, comprising a beam splitter for sampling at relatively low level the entire section of a laser beam, video camera means sensitive to ultraviolet radiation in a samples beam picked off by said splitter, a TV-display of relative intensity of the sampled beam, a video-recorder connected to store one or more frames of the TV display, a horizontal-line grabber connected to the video recorder to segregate a given line of the frame, and an oscilloscope-display device connected to the output of the line grabber to provide an intensity-profile display for the given line of the frame.

Claim 27

Dependent Claim 20 words

The apparatus of claim 21, in which said camera means is a video camera that is sensitive to ultraviolet radiation.

Claim 28

Dependent Claim 39 words

The apparatus of claim 21, in which said camera means is a luminescent plate that is visibly responsive to incident ultraviolet radiation, and a video camera responsive to visible light and focused on a luminescent image at said plate.

Claim 29

Dependent Claim 22 words

The apparatus of claim 21, in which selectively operable means at the line grabber is operative to vertically select the given line.

Claim 30

Dependent Claim 25 words

The apparatus of claim 21, in which said line grabber also includes means for selecting a given vertical alignment of intensity levels in the frame.

Claim 31

Dependent Claim 15 words

The apparatus of claim 21, and including a beam rotator operative upon the beam sample.

Claim 32

Dependent Claim 41 words

The improvement of claim 11, in which said beam-processing means is contained in an enclosure having a beam-entry port proximal to beam exit from the laser and a beam-exit port proximal to the location of characterized beam delivery to the eye.

Claim 33

Dependent Claim 12 words

The improvement of claim 27, in which said enclosure is substantially sealed.

Claim 34

Dependent Claim 20 words

The improvement of claim 27, in which said enclosure has an environmental filling of a gas inert to laser radiation.

Claim 35

Dependent Claim 12 words

The improvement of claim 29, in which said gas is dry nitrogen.

Claim 36

Dependent Claim 144 words

Apparatus for performing an ablating sculpture of the anterior surface of the cornea of an eye, comprising an excimer laser for pulsed emission of ultraviolet radiation in a beam of rectangular section wherein intensity distribution is generally uniform in the longer-dimensional (X-axis) direction and is generally Gaussian about the central elevation of its shorter-dimensional (Y-axis) direction; and optical elements in a path of beam transmission to the eye, for centering the beam on the viewing axis of the eye and for shaping the beam to a circle wherein said generally Gaussian distribution is symmetrical about a diameter of the circle and wherein the diameter of the circle conforms to that of the area of the cornea to be subjected to ablation; said optical elements including beam-rotating means, whereby the orientation of the Gaussian distribution may be subjected to rotation with respect to the eye.

Claim 37

Dependent Claim 144 words

Apparatus for performing an ablating sculpture of the anterior surface of the cornea of an eye, comprising an excimer laser for pulsed emission of ultraviolet radiation in a beam of rectangular section wherein intensity distribution is generally uniform in the longer-dimensional (X-axis) direction and is generally Gaussian about the central elevation of its shorter-dimensional (Y-axis) direction; and optical elements in a path of beam transmission to the eye, for centering the beam on the viewing axis of the eye and for shaping the beam to a circle wherein said generally Gaussian distribution is symmetrical about a diameter of the circle and wherein the diameter of the circle conforms to that of the area of the cornea to be subjected to ablation; said optical elements including beam-rotating means, whereby the orientation of the Gaussian distribution may be subjected to rotation with respect to the eye.

Claim 38

Dependent Claim 43 words

Apparatus according to claim 31, in which said beam-rotating means includes provision for selective rotational adjustment and setting of the orientation of the Gaussian distribution, whereby an astigmatism-correcting change of cornea curvature may be effected for a given laser-beam exposure to the eye.

Claim 39

Dependent Claim 60 words

Apparatus according to claim 31, in which said beam-rotating means includes provision for continuously driven rotation in the course of a given laser-beam exposure to the eye, whereby for beam rotation of at least 180 degrees at the eye and for the direction of a given laser-beam exposure to the eye, a myopia-reducing change of cornea curvature may be effected.

Claim 40

Dependent Claim 58 words

Apparatus according to claim 31, in which said optical elements include anamorphic means interposed between the laser and the beam-rotating means, said anamorphic means being oriented to optically expand the shorter dimension of the rectangular section of the laser beam and thus to change the effective width of the generally Gaussian distribution at eye exposure to the beam.

Claim 41

Dependent Claim 70 words

Apparatus according to claim 31, in which said beam-rotating means includes provision for beam rotation in the course of a given laser exposure to the eye, the rate of rotation being a function of azimuthal orientation of the Gaussian distribution, such that more time is spent at the orientation identifable with an astigmatism to be corrected, as compared with less time spent at the orientation perpendicular to the astigmatism axis.

Sculpture apparatus for correcting curvature of the cornea

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag