Method and systems for laser treatment of presbyopia using offset imaging

Abstract

An ophthalmic surgery system and method for treating presbyopia by performing ablative photodecomposition of the corneal surface. The offset image of a variable aperture, such as a variable width slit and variable diameter iris diaphragm, is scanned in a preselected pattern to perform ablative sculpting of predetermined portions of a corneal surface. The scanning is performed to ablate an optical zone sized to match the patient pupil with a peripheral transition zone outside the pupil. The shape of the ablated optical zone is different from the shape of the final optical correction on the anterior surface of the cornea. The optical zone corrects for near-vision centrally and far-vision peripherally. A movable image displacement mechanism enables radial displacement and angular rotation of the profiled beam exiting from the variable aperture. The invention enables wide area treatment with a laser having a narrower beam than the treatment area, and can be used in the treatment of many conditions in conjunction with presbyopia such as hyperopia, hyperopic astigmatism and irregular refractive aberrations.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 10 / 600,027, filed on Jun. 19, 2003, (Attorney Docket No. 018158-011140US), which is a continuation of U.S. patent application Ser. No. 09 / 901,964, filed on Jul. 9, 2001, now U.S. Pat. No. 6,663,619, (Attorney Docket No. 018158-011120US), which is a division of U.S. patent application Ser. No. 09 / 261,768, filed on Mar. 3, 1999, now U.S. Pat. No. 6,280,435, (Attorney Docket No. 018158-01111US), which claims the benefit of U.S. Patent Application No. 60 / 076,786, filed on Mar. 4, 1998, the full disclosures of which are hereby incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to surgical modifications to the eye. In a specific embodiment, the invention provides ophthalmic surgery techniques which employ a laser to effect ablative photodecomposition of corneal tissue to correct presbyopia and / or other vis...

AI Technical Summary

Benefits of technology

"The invention provides a method and system for ablating the corneal surface to correct presbyopia and hyperopia simultaneously. The ablation is done by ablating a transition zone peripheral to the optical zone and to the pupil. The ablated surface is covered by a new epithelial layer or a repositioned anterior flap of the corneal tissue. The final shape of the anterior surface of the cornea is determined by factors such as corneal healing and the spatial variation of ablation. The invention also provides for scaling the aspheric optical zone to match the pupil size and ablating a transition zone to control the shape of the healed surface within the adjacent optical zone. The technical effects of the invention include minimizing vision degradation, reducing the need for glasses, and improving the predictability and desirability of refractive correction procedures."

Problems solved by technology

One of the major difficulties encountered in the application of laser surgery techniques to effect hyperopic and presbyopic refractive error corrections lies in the nature of the boundary between the optical zone and the untreated area.

This natural phenomenon, sometimes termed the “hyperopic shift” in phototherapeutic keratectomy, causes a lack of precision for a given surgical procedure and diminished predictability, counteracting the beneficial effects of the refractive correction procedure and thereby reducing the desirability of the procedure to the prospective patient.

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