Treatment of presbyopia and other eye disorders using a scanning laser system

Abstract

Presbyopia is treated by a method which uses ablative lasers to ablate the sclera tissue and increase the accommodation of the ciliary body. Tissue bleeding is prevented by an ablative laser having a wavelength of between 0.15 and 3.2 micron. A scanning system is proposed to perform various patterns on the sclera area of the cornea to treat presbyopia and to prevent other eye disorder such as glaucoma. Laser parameters are determined for accurate sclera expansion.REEXAMINATION RESULTSThe questions raised in reexamination request no. 90 / 006,090, filed Aug. 22, 2001, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e), for ex parte reexaminations, or the reexamination certificate required by 35 U.S.C. 316 as provided in 37 CFR 1.997(e) for inter partes reexaminations.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to methods and apparatus for the treatment of presbyopia and the treatment and prevention of glaucoma using dual-beam scanning lasers.[0003]2. Prior Art[0004]Corneal reshaping, including a procedure called photorefractive keratectomy (PRK) and a new procedure called laser assisted in situ keratomileusis, or laser intrastroma keratomileusis (LASIK), has been performed by lasers in the ultraviolet (UV) wavelength of 193-213 nm. Commercial UV refractive lasers include ArF excimer lasers at 193 nm and other non-excimer, solid-state lasers, such as the one patented by the present inventor in 1992 (U.S. Pat. No. 5,144,630). Precise, stable corneal reshaping requires lasers with strong tissue absorption (or minimum penetration depth) such that the thermal damage zone is at a minimum (less than few microns). Furthermore, accuracy of the procedure of vision correction depends on the amount of tissue...

AI Technical Summary

Benefits of technology

[0015]It is yet another preferred embodiment of the present invention to provide a scanning mechanism to effectively ablate the sclera tissue at a controlled depth by beam overlapping.

[0016]It is yet another preferred embodiments of the present invention to provide an apparatus and method such that both the ablative and the coagulative lasers can have applied to their beams the corneal surface to thereby prevent bleeding during the procedure.

[0018]It is yet another embodiment of the present invention to provide a coagulative laser to prevent the sclera tissue bleeding when a diamond knife is used for the incision of the sclera.

[0019]It is yet another embodiment of the present invention to use a metal mask on the corneal surface to generate a small slit when the laser is scanning over the mask. In this embodiment, the exact laser spot size and its propagating stability are not critical.

[0020]It is yet another embodiment of the present invention to provide an integration system in which the sclera expansion leads to the increase of the accommodation of the ciliary muscle for the treatment of presbyopia and the prevention of open angle glaucoma.

Problems solved by technology

The above-described prior arts are however limited to the use of reshaping the corneal surface curvature for the correction of myopia and hyperopia.

These mechanical approaches have the drawbacks of complexity and are time consuming, costly and have potential side effects.

However, these prior arts do not present any details or practical methods or laser parameters for the presbyopic corrections.

No clinical studies have been practiced to show the effectiveness of the proposed concepts.

The concepts proposed in the Schaker patents regarding lasers suitable for expanding the sclera tissues were incorrect in that the proposed lasers did not identify those which are “cold lasers” and can only conduct the tissue ablation rather than thermal burning of the cornea.

Furthermore, the clinical issues, such as accuracy of the sclera tissue removal and potential tissue bleeding during the procedures, were not indicated in these prior patents.

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