Laser corneal surgery
First Claim
1. A method of reprofiling a cornea to correct a refractive error in an eye, the method comprisingaligning a laser means for delivering a pulsed beam of laser radiation to the cornea, with an optical axis of a cornea, the cornea having an epithelial surface, an underlying stroma and a Bowman'"'"'s membrane disposed between the epithelial surface and the stroma;
- selectively ablating and reshaping the cornea with an erodable means for masking said radiation, the masking means being disposed between the laser means and the surface, wherein the masking means has a selected composition and thickness, is erodable by radiation from the laser means and has a pre-defined profile of resistance to erosion by laser radiation such that upon irradiation a portion of the radiation is selectively absorbed by the masking means and another portion is transmitted to the surface of the cornea in accordance with the profile of the masking means to selectively erode the surface; and
controlling the laser radiation so that ablation terminates substantially within the Bowman'"'"'s membrane and not the underlying stroma.
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Accused Products
Abstract
A method and system for reshaping Bowman'"'"'s membrane, which lies directly below the anterior epithelial surface of the cornea, to provide correction of refractive errors in the eye by photoablation of selective regions of the Bowman'"'"'s membrane without substantial penetration into the stroma of the eye is disclosed including a laser and a beam-shaping mask, disposed between the laser and the surface of the cornea, which imposes a defined ablation profile upon the Bowman'"'"'s membrane by laser radiation. The system can also include a feedback control for measuring the effectiveness of the laser during operation and for controlling the laser such that the reprofiling operation is substantially confined to the Bowman'"'"'s membrane throughout the procedure. The beam-shaping mask can include either an aperture e.g., a beam-shaping stop means alone or in combination with a beam-shaping window, or an mask which is erodible or otherwise graded in its absorptive capacity to present a predefined profile of resistance to the laser radiation.
152 Citations
25 Claims
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1. A method of reprofiling a cornea to correct a refractive error in an eye, the method comprising
aligning a laser means for delivering a pulsed beam of laser radiation to the cornea, with an optical axis of a cornea, the cornea having an epithelial surface, an underlying stroma and a Bowman'"'"'s membrane disposed between the epithelial surface and the stroma; -
selectively ablating and reshaping the cornea with an erodable means for masking said radiation, the masking means being disposed between the laser means and the surface, wherein the masking means has a selected composition and thickness, is erodable by radiation from the laser means and has a pre-defined profile of resistance to erosion by laser radiation such that upon irradiation a portion of the radiation is selectively absorbed by the masking means and another portion is transmitted to the surface of the cornea in accordance with the profile of the masking means to selectively erode the surface; and controlling the laser radiation so that ablation terminates substantially within the Bowman'"'"'s membrane and not the underlying stroma. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for reprofiling a corneal surface, the system comprising
laser means for delivering a pulsed beam of laser radiation to the cornea, said laser means being adapted for alignment with an optical axis of a cornea, the cornea having an epithelial surface, an underlying stroma and a Bowman'"'"'s membrane disposed between the epithelial surface and the stroma; -
beam-shaping means disposable between the laser means and the cornea for selectively ablating and reshaping the cornea wherein the beam-shaping means further includes an erodable means for masking said radiation, the masking means being disposed between the laser means and the corneal surface, wherein the masking means has a selected composition and thickness, is erodable by radiation from the laser means and has a pre-defined profile of resistance to erosion by laser radiation such that upon irradiation a portion of the radiation is selectively absorbed by the masking means and another portion is transmitted to the surface of the cornea in accordance with the profile of the masking means to selectively erode the surface; and control means for controlling the laser radiation so that ablation terminates substantially within the Bowman'"'"'s membrane and not the underlying stroma. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A continuous procedure for laser reprofiling a cornea to correct a refractive error in the eye, said procedure comprising:
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aligning a laser means for delivering a pulsed beam of laser radiation to the cornea in position relative to a cornea, the cornea having an epithelial surface, an underlying stroma and a Bowman'"'"'s membrane disposed between the epithelial surface and the stroma; ablating an area of the cornea by delivering pulses of laser radiation to the cornea, such that portions of said epithelial surface and Bowman'"'"'s membrane are ablated concurrently by cumulative exposure to the laser radiation using an erodable mask disposed between said laser means and said epithelial layer, wherein said mask has a selected composition and thickness, is erodable by radiation from the laser means and has a predetermined profile of resistance to erosion by laser radiation such that upon irradiation, said mask erodes in a manner such as to achieve said ablation profile in said Bowman'"'"'s membrane; varying the area of the cornea to which pulses are delivered to selectively ablate and reshape the cornea; and controlling the laser radiation so that ablation terminates substantially within Bowman'"'"'s membrane and not the underlying stroma. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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Specification