EP0346116A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for laser sculpture of the cornea
Assignee: AMO Manufacturing USA LLC
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Filing: 1989-06-08
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Granted: —
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Expires: 2009-06-08
Abstract
Abstract In use of laser radiation to ablate corneal tissue, to achieve a sculptured change in curvature of the optically used region of the cornea, a variable magnification (zoom) lens is combined with different sized apertures of an indexible mask to develop a relatively smooth profile for the changed curvature. The zoom-lens settings are varied in the course of cornea exposure through each of the succession of mask apertures. To do this, the range of zoom-lens magnification can always be less than 2:1, yet the zoom-lens system can effectively reduce to insignificance the stepped profiling that is inherent in reliance only upon the indexed aperture technique. Also described are techniques to achieve compensation for delivered flux-density variation as a function of instantaneous zoom-lens setting, and programmable control of the area of delivered flux density in a manner to correct for parabolic or other fall-off in delivered beam intensity as a function of radius outward of the axis of beam delivery.
Inventors
- 👤 Paul R. Yoder, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 15:09
CPC Classifications
A; A61; A61F; A61F9/00; A61F9/007; A61F9/008; A61F9/00802; A61F9/00817; A61F9/00804; B; B23; B23K; B23K26/00; B23K26/02; B23K26/06; B23K26/064; B23K26/066; A61F2009/00861; A61F2009/00872
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
166 words
In sculpture apparatus for curvature-generating operation upon the anterior surface of the cornea of an eye, wherein laser means produces a tissue-ablating output beam and controllable means is provided for variably limiting the sectional area of said beam at impingement on the cornea, and wherein the area variation is over a range which at least includes a maximum optically used area to be ablated and is symmetrical with respect to a beam-projection axis which coincides with the optical axis of the eye, the improvement wherein said controllable means includes (a) a zoom-lens system and (b) at least one indexible mask having a plurality of mask apertures of progressively changing area, and control means connected to said laser means and to said controllable means for so controlling zoom-lens setting for each of an indexed plurality of apertures of said mask as to produce a relatively smooth variation of the sectional area of said beam at impingement on the cornea with an accompanying diopter change at the cornea.
Claim 2
Dependent Claim
166 words
In sculpture apparatus for curvature-generating operation upon the anterior surface of the cornea of an eye, wherein laser means produces a tissue-ablating output beam and controllable means is provided for variably limiting the sectional area of said beam at impingement on the cornea, and wherein the area variation is over a range which at least includes a maximum optically used area to be ablated and is symmetrical with respect to a beam-projection axis which coincides with the optical axis of the eye, the improvement wherein said controllable means includes (a) a zoom-lens system and (b) at least one indexible mask having a plurality of mask apertures of progressively changing area, and control means connected to said laser means and to said controllable means for so controlling zoom-lens setting for each of an indexed plurality of apertures of said mask as to produce a relatively smooth variation of the sectional area of said beam at impingement on the cornea with an accompanying diopter change at the cornea.
Claim 3
Dependent Claim
46 words
Sculpture apparatus according to claim 1, wherein said controllable means further includes means for varying the intensity of the laser beam, said control means being so continuously connected for control of zoom-lens setting as to compensate for flux-density dilution as a function of instantaneous zoom-lens magnification.
Claim 4
Dependent Claim
29 words
Sculpture apparatus according to claim 2, wherein said control means includes a microprocessor having an intensity-control connection to said laser means and a magnification-control connection to said zoom-lens system.
Claim 5
Dependent Claim
23 words
Sculpture apparatus according to claim 2, wherein said control means includes variable-density filter means interposed between said laser means and said zoom-lens system.
Claim 6
Dependent Claim
39 words
Sculpture apparatus according to claim 4, wherein said variable-density filter means comprises two like variable-density filters in mutually opposite directions of varying density and coupled for opposing displacements through the laser beam in synchronism with variation of zoom-lens setting.
Claim 7
Dependent Claim
98 words
Sculpture apparatus according to claim 1, in which said mask is one of a plurality of circular masks which are in axially separated array and which are so connected to said control means as to be separately indexible about the same axis of index rotation, each of said masks having a differently characterized progression of apertures of varying beam-transmitting sectional area, and one of the apertures of each mask having an opening of such sufficiently large beam-transmitting sectional area as to avoid beam-section limitation upon the beam-section-limiting ability of any aperture of any other mask of said plurality.
Claim 8
Dependent Claim
94 words
Sculpture apparatus according to claim 1 or claim 6, in which said at least one indexible mask includes an opening of outer radius which when projected to the cornea via said zoom-lens system is greater than that of the maximum optically used area to be ablated, said controllable means further including iris means for varying said outer radius, and said control means so coordinating iris setting with zoom-lens setting and with currently indexed mask aperture as to effect a relatively smoothly beveled annular zone of blending slope outwardly from said maximum optically used area.
Claim 9
Dependent Claim
127 words
Sculpture apparatus according to claim 1 or claim 6, in which the apertures of said at least one of said masks are circularly annular and of progressively changing inner radius, and in which said apertures are of outer radius which when projected to the cornea via said zoom-lens system is greater than that of the maximum optically used area to be ablated, said controllable means further including iris means for varying said outer radius, said control means so coordinating iris opening with zoom-lens setting and with the currently indexed mask aperture as to effect a relatively smoothly profiled hyperopia-correcting diopter change within said maximum curvature-correcting area and also to effect a relatively smoothly beveled annular zone of blending slope outwardly from said area of diopter-changing curvature correction.
Claim 10
Dependent Claim
39 words
Sculpture apparatus according to claim 1 or claim 6, in which the mask apertures of said at least one of said masks are circular and of progressively changing radius, whereby to effect a relatively smoothly profiled myopia-correcting diopter change.
Claim 11
Dependent Claim
63 words
Sculpture apparatus according to claim 1 or claim 6, in which the mask apertures of said at least one of said masks are elongate rectangular and of progressively changing lateral width, and selectively operable means for orienting the elongation axes of said apertures in accordance with a predetermined orientation of desired astigmatism correction, whereby to effect a relatively smoothly profiled cylindrical diopter change.
Claim 12
Dependent Claim
76 words
Sculpture apparatus according to claim 1, in which said controllable means includes shutter means operable to preclude laser-beam impingement at the cornea, said control means being operative to preclude laser-beam impingement at the cornea upon completion of beam exposure for each utilized mask aperture and for the period (1) of mask-indexing into the operative position of the next mask aperture in said progression and (2) of zoom-lens resetting for operative use of said next mask aperture.
Claim 13
Dependent Claim
69 words
Sculpture apparatus according to claim 1, in which the number of mask apertures and the relation of area change between one and the next mask aperture through the progression of area change is selected for limitation of requisite zoom-lens magnification to the range 1:2 or less, for each of the indexed positions of said mask, whereby the variation in energy density at the cornea is within the range 1:4.
Claim 14
Dependent Claim
69 words
Sculpture apparatus according to claim 1, in which the number of mask apertures and the relation of area change between one and the next mask aperture through the progression of area change is selected for limitation of requisite zoom-lens magnification to the range 1:1.414 or less, for each of the indexed positions of said mask, whereby the variation in energy density at the cornea is within the range 1:2.
Claim 15
Dependent Claim
70 words
Apparatus for laser sculpture of the cornea comprising a variable magnification (zoom) lens in the laser beam path, at least one mask having a plurality of different mask apertures selectively introducable into the laser beam path, and means for controllably adjusting the zoom lens setting in the course of cornea exposure through each of a series of mask apertures so as to obtain a substantially smooth change in cornea profile.
Claim 16
Dependent Claim
70 words
Apparatus for laser sculpture of the cornea comprising a variable magnification (zoom) lens in the laser beam path, at least one mask having a plurality of different mask apertures selectively introducable into the laser beam path, and means for controllably adjusting the zoom lens setting in the course of cornea exposure through each of a series of mask apertures so as to obtain a substantially smooth change in cornea profile.
References Cited (Backward Citations)
No citation records indexed.
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