EP0280414A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Sculpture apparatus for correcting curvature of the cornea
Assignee: AMO Manufacturing USA LLC
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Filing: 1988-01-29
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Granted: —
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Expires: 2008-01-29
Abstract
Abstract In the context of ultraviolet-laser sculpting of the cornea to achieve optical correction through a newly shaped anterior surface, the invention subjects the laser beam to certain shaping and homogenizing operations prior to any attempt to specially characterize the beam for a particular sculpture procedure. In a preferred embodiment, an excimer laser (11) produces a beam of rectangular section, and the short dimension of this section is optically expanded (50, 51) to produce a beam section having quadrature profiles of substantially equal extent on opposite sides of the central axis of the expanded beam; the expanded beam is thereafter subjected to optical rotation (52) in the course of a given surgical exposure to the cornea, whereby irregularity in the intensity profile of the expanded beam is converted to an irregularity of rotational symmetry. A compensating filter (55) having an attenuating profile of rotational symmetry effectively offsets irregularity of circular symmetry in the time-integrated product of beam rotation.
Inventors
- 👤 William B. Telfair
- 👤 Paul R. Yoder, Jr.
- 👤 Clifford A. Martin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 11:31
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/64; G02B27/642; A; A61; A61F; A61F9/00; A61F9/007; A61F9/008; A61F9/00802; A61F9/00804; A61F9/00817; A61F2009/00844; A61F2009/00861; A61F2009/00872; A61F2009/00878; A61F2009/00882
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
194 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 as to achieve a new and improved corneal curvature, the improvement wherein the laser is an excimer laser producing a beam of section which is elongate in the width dimension and which is relatively narrow in the height dimension, 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 anamorphic beam-expansion means oriented to expand the relatively narrow height dimension to substantially the elongate extent of the width dimension, and beam-rotation means positioned to rotate the expanded beam about a generally central axis prior to characterizing the flux distribution within the predetermined circle.
Claim 2
Dependent Claim
194 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 as to achieve a new and improved corneal curvature, the improvement wherein the laser is an excimer laser producing a beam of section which is elongate in the width dimension and which is relatively narrow in the height dimension, 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 anamorphic beam-expansion means oriented to expand the relatively narrow height dimension to substantially the elongate extent of the width dimension, and beam-rotation means positioned to rotate the expanded beam about a generally central axis prior to characterizing the flux distribution within the predetermined circle.
Claim 3
Dependent Claim
24 words
The improved apparatus of claim 1, in which the axis of beam rotation is substantially coincident with the central axis of the expanded beam.
Claim 4
Dependent Claim
29 words
The improved apparatus of claim 1, in which the axis of beam rotation is offset from the central axis of the expanded beam and/or is tilted with respect thereto.
Claim 5
Dependent Claim
14 words
The improved apparatus of claim 3, in which said offset and/or tilt is fixed.
Claim 6
Dependent Claim
26 words
The improved apparatus of claim 3, in which said offset and/or tilt is variable in a fixed direction transverse to the axis of the expanded beam.
Claim 7
Dependent Claim
31 words
The improved apparatus of claim 1, in which said beam-rotation means is positioned to eccentrically gyrate the expanded beam about an axis which optically intersects the center of the predetermined circle.
Claim 8
Dependent Claim
40 words
The improved apparatus of any one of claims 1 to 6, in which said beam-homogenizing means includes a scraper for limiting the homogenized beam to a beam of circular section, whereby flux distribution may be characterized over the circular section.
Claim 9
Dependent Claim
52 words
The improved apparatus of any one of claims 1 to 6, in which said beam-homogenizing means includes a scraper for limiting the homogenized beam to a beam of circular section, said scraper being interposed between said beam-expansion means and said beam-rotation means, whereby flux distribution may be characterized over the circular section.
Claim 10
Dependent Claim
51 words
The improved apparatus of any one of claims 1 to 6, in which said beam-homogenizing means includes a scraper for limiting the homogenized beam to a beam of circular section, said scraper being at a location downstream from said beam-rotation means, whereby flux distribution may be characterized over the circular section.
Claim 11
Dependent Claim
58 words
The improved apparatus of any one of claims 1 to 6, in which said beam-homogenizing means includes a scraper for limiting the homogenized beam to a beam of circular section, said scraper being defined by a circular filter aperture wherein the filter is characterized by an attenuation profile selected for achievement of a predetermined change in cornea curvature.
Claim 12
Dependent Claim
48 words
The improved apparatus of any one of claims 1 to 6, in which said beam-homogenizing means includes a filter having an attenuation profile of rotational symmetry selected to effectively compensate a rotationally symmetrical irregularity in the time-integrated sectional intensity profile of laser-beam propagation issuing from said beam-rotation means.
Claim 13
Dependent Claim
83 words
The improved apparatus of any one of claims 1 to 6, in which said beam-homogenizing means includes a filter having an attenuation profile of rotational symmetry selected to effectively compensate a rotationally symmetrical irregularity in the time-integrated sectional intensity profile of laser-beam propagation issuing from said beam-rotation means, the characterizing of flux distribution to achieve a new and improved corneal curvature being a filter having a characterizing attenuation profile in which said attenuation profile of rotational symmetry is embodied as a corrective component.
Claim 14
Dependent Claim
83 words
The improved apparatus of claim 1, (a) in which the height and width dimensions of the expanded beam are substantially greater than the beam-section dimensions at delivery to the eye, (b) in which beam characterization is at a circular aperture, and (c) in which beam-condenser means reduces said aperture to said predetermined circle and comprises lens means imaging said aperture at or near the eye, whereby the focal point for laser radiation occurs at an axial offset from beam incidence upon the eye.
Claim 15
Independent Claim
159 words
The method of preparing an ultraviolet laser beam for intensity-distributed characterization over a circular section area in order that the characterized circular beam may be used to effect a curvature change in the anterior surface of a cornea, thereby to change optical properties of an eye by selectively ablating the anterior surface with penetration into the stroma to achieve over a period of treatment time a volumetric removal of corneal tissue, which method comprises selecting an excimer laser to produce an output beam of generally rectangular two-dimensional section wherein one of the dimensions substantially exceeds the other dimension, optically expanding said other dimension to substantially the extent of said one dimension, whereby the beam section has quadrature profiles of substantially equal extent on opposite sides of the central axis of an expanded beam, and optically rotating the expanded beam, thereby in the course of such optical rotation to effectively deliver for subsequent intensity-distributed characterization a beam having rotational symmetry.
Claim 16
Independent Claim
159 words
The method of preparing an ultraviolet laser beam for intensity-distributed characterization over a circular section area in order that the characterized circular beam may be used to effect a curvature change in the anterior surface of a cornea, thereby to change optical properties of an eye by selectively ablating the anterior surface with penetration into the stroma to achieve over a period of treatment time a volumetric removal of corneal tissue, which method comprises selecting an excimer laser to produce an output beam of generally rectangular two-dimensional section wherein one of the dimensions substantially exceeds the other dimension, optically expanding said other dimension to substantially the extent of said one dimension, whereby the beam section has quadrature profiles of substantially equal extent on opposite sides of the central axis of an expanded beam, and optically rotating the expanded beam, thereby in the course of such optical rotation to effectively deliver for subsequent intensity-distributed characterization a beam having rotational symmetry.
Claim 17
Dependent Claim
46 words
The method of claim 14, including the further step of filtering the beam which results from beam rotation, the filtering step being according to an attenuation profile of rotational symmetry, which profile is selected to compensate for an irregularity of circular symmetry resulting from beam rotation.
Claim 18
Dependent Claim
28 words
Laser apparatus for ophthalmological surgery including beam rotation means provided in the laser beam path for alleviating the effects of irregular beam intensity distribution across the beam cross-section.
Claim 19
Dependent Claim
28 words
Laser apparatus for ophthalmological surgery including beam rotation means provided in the laser beam path for alleviating the effects of irregular beam intensity distribution across the beam cross-section.
References Cited (Backward Citations)
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