Method and system for ablating surfaces with partially overlapping craters having consistent curvature
First Claim
1. A method of sculpting a region on a surface of a tissue with a pulsed energy beam to effect a predetermined change in overall shape, the method comprising:
- directing a pulsed beam of an ablative energy toward the tissue surface;
ablating a plurality of craters in the pulsed beam, wherein each pulse of the beam ablates a single associated crater having an associated crater surface extending distribution profile adjacent the tissue surface so that the associated crater surface has a consistent curvature and ablating the associated shape from a flat surface would provide a negative optical power over most of the associated crater surface; and
scanning the beam over the region to effect the predetermined change in overall shape in the region by partially overlapping the plurality of consistently curved craters.
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Accused Products
Abstract
A technique for laser sculpting a predetermined shape on an exposed corneal surface by ablating a sequence of consistently curved craters with individual pulses of a laser beam. An initial laser beam energy pattern is shaped by a laser beam shaping element to make a consistently curved laser beam energy pattern. The consistently curved laser beam ablates a consistently curved crater in the surface with a single pulse of the laser beam. A computer controls the position of the laser beam and scans the laser beam over the surface to sculpt the predetermined shape in an ablation zone on the exposed surface. A sequence of partially overlapping craters is distributed over the ablation zone. In some embodiments diffractive optics are used as a beam shaping element. In additional embodiments, the consistently curved crater is a uniformly curved spherical crater.
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Citations
47 Claims
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1. A method of sculpting a region on a surface of a tissue with a pulsed energy beam to effect a predetermined change in overall shape, the method comprising:
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directing a pulsed beam of an ablative energy toward the tissue surface;
ablating a plurality of craters in the pulsed beam, wherein each pulse of the beam ablates a single associated crater having an associated crater surface extending distribution profile adjacent the tissue surface so that the associated crater surface has a consistent curvature and ablating the associated shape from a flat surface would provide a negative optical power over most of the associated crater surface; and
scanning the beam over the region to effect the predetermined change in overall shape in the region by partially overlapping the plurality of consistently curved craters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A laser system for sculpting an ablated region on a surface of a tissue, the tissue having a threshold of ablation, the system comprising:
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a laser for making a pulsed beam of a ablative laser energy;
a beam energy shaping element disposed in a path of the pulsed beam, the shaping element changing a laser beam energy pattern of the pulsed beam to a shaped beam, the shaped beam comprising a consistently curved laser beam energy distribution pattern above the threshold of ablation, the energy pattern creating a consistently curved crater depth profile on the surface of the tissue with each pulse, a majority of the crater depth profile having a concave surface; and
,a scanning element for moving the shaped beam over the region to sculpt the region with a plurality of partially overlapping pulses of the ablative energy. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 36, 38)
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33. A method of sculpting a region on a tissue surface with a pulsed laser beam to shape the region to a predetermined shape, the method comprising:
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making a pulsed beam of an ablative energy;
shaping the laser beam with a beam shaping element by diffracting the laser beam with a diffracting element and changing a phase of the beam with the diffracting element by transmitting the beam through the diffracting element to form the shaped beam with a portion of the beam passing through the element;
restricting a cross sectional area of the beam;
forming an image of the restricted beam near the region;
ablating a crater having a substantially uniform curvature in the tissue with a single pulse of the beam wherein the substantially uniform curvature comprises a crater shape having a negative optical power with a substantially constant magnitude, a dimension across the crater being about 5 to 80% of a dimension across the region;
deflecting the beam;
rotating the laser beam shaping element between pulses of the laser beam; and
,scanning the beam over the region to form the shape in the region by partially overlapping a sequence of uniformly curved craters, the sequence of craters being distributed over the region to cover a dimension across the region and the dimension across the craters being substantially uniform among the craters of the sequence. - View Dependent Claims (34)
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35. A method of sculpting an ablated region on an exposed corneal surface with a pulsed energy beam to shape the region to a predetermined shape, the method comprising:
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making a pulsed beam of an ablative energy, each pulse of the beam having an energy distribution profile at the corneal surface;
ablating a crater in the corneal surface with a single pulse of the beam, wherein the crater has a crater surface extending along the corneal surface which reflects the energy distribution profile, and wherein the crater has a consistent curvature comprising a concave shape over the majority of the crater surface when ablated in a flat surface; and
,scanning the beam over the region to form the predetermined shape in the region by partially overlapping a plurality of the consistently curved craters, the plurality of craters being distributed over the region to cover a dimension across the region.
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37. A method of sculpting an ablated region on an exposed corneal surface with a pulsed laser beam to shape the region to a predetermined curved shape, the method comprising:
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making a pulsed beam of an ablative energy, the beam having an energy distribution profile;
shaping the laser beam with a beam shaping element by diffracting the laser beam with a diffracting element and changing a phase of the beam with the diffracting element by transmitting the beam through the diffracting element to form the shaped beam with a portion of the beam passing through the element;
restricting a cross sectional area of the beam by transmitting the beam through an aperture formed in a non-transmitting material that blocks a portion of the beam;
forming an image of the restricted beam near the region;
ablating a crater having a substantially uniform curvature in the tissue with a single pulse of the beam, wherein the substantially uniform curvature comprises a negative optical power with a substantially constant magnitude, a dimension across the crater being about 5 to 80% of a dimension across the region;
deflecting the beam with an optical element selected from the group consisting of lenses, prisms and mirrors;
rotating the laser beam shaping element between pulses of the laser beam to average the shaped beam; and
,scanning the beam over the region to form the shape in the region by partially overlapping a sequence of uniformly curved craters, the plurality of craters being distributed over the region to cover a dimension across the region and the dimension across the craters being substantially uniform among the craters of the sequence.
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39. A laser system for sculpting an ablated region on an exposed surface of a cornea to a predetermined curved shape, the cornea having a threshold of ablation, the system comprising:
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a pulsed laser for making a pulsed beam of an ablative laser energy;
a laser beam shaping element for changing a laser beam energy pattern of the pulsed beam to a shaped beam, the shaped beam comprising a substantially spherical laser beam energy distribution pattern with a region of the substantially spherical pattern above the threshold of ablation so as to create a consistently curved crater having a crater shape with a consistent radius of curvature providing negative optical power over substantially the ablated crater surface;
a boundary enclosing the above threshold region and an intensity of the beam around the boundary being a proportion of the threshold of ablation, the proportion being in a range of 100 to 110%;
an aperture formed in a non-transmitting material for restricting a cross sectional area of the beam by passing the beam through the aperture;
an imaging lens for forming an image of the beam passing through the aperture, the image being formed near the ablated region;
a scanning element for moving the shaped beam over the region to sculpt the region to the shape with a sequence of partially overlapping pulses of the ablative energy wherein the scanning element comprises an optical element selected from the group consisting of lenses prisms and mirrors; and
,a computer for controlling a position of the beam over the region according to a coordinate reference stored in the computer, the coordinate reference partially overlapping the consistently curved pattern among the pulses of the sequence.
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40. A method of sculpting a region an a surface of a tissue with a pulsed energy beam to effect a predetermined change in overall shape, the method comprising:
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directing a pulsed laser beam toward the tissue surface;
shaping the pulsed laser beam with a diffracting element to create an energy distribution profile, wherein each pulse of the beam ablates a single associated crater having an associated crater surface extending along the tissue surface and an associated crater shape, each pulse having the energy distribution profile adjacent the tissue surface so that the associated crater surface has a consistent curvature and ablating the associated shape from a flat surface would provide a negative optical power over most of the associated crater surface, ablating a plurality of consisting curved craters in the tissue with the energy distribution profile of pulsed beam; and
scanning the beam over the region to effect the predetermined change in overall shape in the region by partially overlapping the plurality of consistently curved craters. - View Dependent Claims (41, 42)
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43. A laser system for sculpting an ablated region on a surface of a tissue, the tissue having a threshold of ablation, the system comprising:
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a laser for making a pulsed beam of an ablative laser energy;
a diffractive optical element disposed in a path of the pulsed beam, the element changing a laser beam energy pattern of the pulsed beam to a shaped beam, the shaped beam comprising a consistently curved laser beam energy distribution pattern above the threshold of ablation, the energy pattern creating a consistently curved crater depth profile on the surface of the tissue with each pulse, a majority of the crater depth profile having a concave surface; and
,a scanning element for moving the shaped beam over the region to sculpt the region with a plurality of partially overlapping pulses of the ablative energy. - View Dependent Claims (44, 45, 46, 47)
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Specification