Method and device for corneal shaping and refractive correction

• US 6,033,418 A
• Filed: 05/27/1999
• Issued: 03/07/2000
• Est. Priority Date: 04/25/1997
• Status: Expired due to Fees

• Current Assignee: New Jersey Institute of Technology
• Original Assignee: New Jersey Institute of Technology
• Inventors: L'Esperance, Francis A. Jr., Gordon, Eugene I., Geskin, Ernest S.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): TRUONG, KEVIN THAO
• Application Number:
  US09/320,698
• Time in Patent Office: 285 Days
• Field of Search: 606/166, 606/1, 606/167, 606/159, 606/174
• US Class Current: 606/166
• CPC Class Codes: A61B 17/3203 Fluid jet cutting instruments
• CPC Class Codes: A61B 2017/00017 Electrical control of surgical instruments
• CPC Class Codes: A61F 9/013 Instruments for compensation of ocular refraction A61F9/008 takes precedence; Instruments for use in cornea removal, for reshaping or performing incisions in the cornea

Abstract

The device for benign, non-surgical external shaping of corneal tissue to compensate, by refractive correction, for deviations from normal focussing. The jet is directed to erode corneal tissue to provide an increase in curvature to correct for far-sightedness i.e., to refocus a perceived image from beyond retina onto the surface of the retina.

Claims

1. A system for effecting a refractive keratectomy upon corneal tissue, comprising:

water supply means;

nozzle means connected to said water supply means and being positionable with respect to a spaced target cornea to form a water jet having a diameter at the cornea tissue target of from 2 to 20 mils diameter;

positioning means for controllably displacing the impact point of said jet upon said cornea tissue to conform to a desired pattern;

means for controlling the mechanical energy transferred by said jet at each point of its impact with said tissue, to thereby effect controlled erosion of said tissue at the said points to enable a required refractive correction; and

a liquid coupling means between said nozzle means and the target cornea tissue, for surrounding and enveloping said water jet in a liquid bath to thereby preclude entrainment of tissue-damaging gasses by the said jet.

2. A system in accordance with claim 1, wherein said means for controlling the energy transferred to said tissue, comprises means for controlling the pressure of said water jet as a function of its point of impact on said tissue.

3. A system in accordance with claim 2, wherein said pressure control means modulates the pressure to achieve an impact velocity at said tissue in the range of 225 to 300 m/sec.

4. A system in accordance with claim 2, wherein said positioning means effects a scan pattern of said jet over said cornea tissue.

5. A system in accordance with claim 1, wherein said coupling means comprises a cup for surrounding in water tight relationship the eye of a patient who is undergoing said keratectomy, said cup being open at its end remote from said eye to receive the said nozzle means in the liquid containable therein.

6. In a system for effecting refractive correction for deviations of an eye imaging system comprised of a cornea with an exposed front surface;

a pupil;

a lens; and

a retina;

from focusing perceived images directly on the retina of the eye;

said system comprising means for removing selected external portions of tissue from the front surface of the cornea, in an area defined by a maximum dilation of the pupil of the eye, whereby curvature of the front surface of the cornea is changed to a sufficient extent, whereby light rays from any point in a perceived image, passing through the cornea and the lens, are substantially optimally focused thereafter on the retina;

THE IMPROVEMENT COMPRISING;

said means for removing said selected portions of said tissue comprises means for impinging said tissue with at least one water jet having an impact velocity of at least 200 meters/second; and

means for moving the water jet relative to the cornea to provide controlled removal of said portions of tissue to effect said change in curvature at the front surface of the cornea.

7. A system in accordance with claim 6, further comprising:

water supply means;

nozzle means connected to said water supply means and being positionable with respect to a spaced target cornea to form a said water jet having a diameter at the cornea tissue target of from 2 to 20 mils diameter; and

a liquid coupling means between said nozzle means and the target cornea tissue, for surrounding and enveloping said water jet in a liquid bath to thereby preclude entrainment of tissue-damaging gasses by the said jet.