Laser surgery method

• US 5,108,388 A
• Filed: 10/16/1987
• Issued: 04/28/1992
• Est. Priority Date: 12/15/1983
• Status: Expired due to Term

• Current Assignee: Amo Manufacturing Usa, Llc (Johnson & Johnson)
• Original Assignee: VISX Incorporated
• Inventors: Trokel, Stephen L.
• Primary Examiner(s): Shay, David M.
• Application Number:
  US07/109,812
• Time in Patent Office: 1,656 Days
• Field of Search: 128/303.1, 128/395, 606/5, 606/3, 606/13
• US Class Current: 606/5
• CPC Class Codes: A61B 2017/00761 Removing layer of skin tissue, e.g. wrinkles, scars or cancerous tissue
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61F 9/00804 Refractive treatments
• CPC Class Codes: A61F 9/00817 Beam shaping with masks

Abstract

An argon-flouride excimer laser or other laser source capable of generating far-ultraviolet radiation at 193 nm is pulsed with energy densities of greater than 20 mj per cm² at a repetition rate up to 25 pulses per second to direct its radiation through a mask and onto corneal tissue, or other biological matter, to form a groove therein of predetermined configuration and depth by a process of ablative photodecomposition. The masks are formed with a slit, circular, crescent or other openings of widths between 30 and 800 microns, and may even be formed to provide a graded intensity center to edge. The mask is reflective or composed of or faced with an organic polymer to prevent heat build-up. Each micron of the depth of a 200 micron deep groove formed in corneal tissue, for example, resulted from the application of 1 joule per square centimeter of radiation, from a series of pulses delivered at intensities of between 100 mj and 200 mj per square centimeter and at a laser pulse rate of between 1 and 25 Hertz; the entire groove taking 100 seconds.

Claims

1. A method for producing a surgical excision of controlled depth and shape in a cornea by ablative photochemical decomposition of corneal tissue without thermal damage to the corneal tissue, said method comprising the steps of:

(a) generating a laser beam in the far ultraviolet region of the energy spectrum and at a wavelength selected to produce ablative photochemical decomposition of corneal tissue without thermal damage to the corneal tissue and

(b) directing said radiation in a controlled manner onto said corneal tissue to induce ablative photochemical decomposition thereof in a volumetric removal of said corneal tissue without thermal heating to create a surgical excision of controlled depth and shape with depth penetration into the stroma.

2. The method of claim 1 wherein said selected wavelength is 193 nanometers.

3. A method for producing a surgical excision of controlled depth and shape in a cornea by ablative photochemical decomposition of corneal tissue without thermal damage to the corneal tissue, said method comprising the steps of:

(a) generating a laser beam at a wavelength of 193 nanometers;

(b) directing said laser beam onto a predetermined area of corneal tissue; and

(c) controlling said laser beam so as to induce ablative photochemical decomposition of said corneal tissue in a volumetric removal of said corneal tissue without thermal damage to said corneal tissue to create a surgical excision of controlled depth and shape with depth penetration into the stroma.

4. The method of changing optical properties of an eye by operating solely upon the anterior surface of the cornea of the eye, which method comprises selective ultraviolet irradiation and attendant ablative photodecomposition of the anterior surface of the cornea in a volumetric removal of corneal tissue and with depth penetration into the stroma and to a predetermined curvature profile.

5. The method of using an ultraviolet laser to change the optical properties of an eye, which method comprises adjusting the intensity of laser beam projection to a level at which laser beam projection onto the anterior surface of the cornea of the eye will result in corneal-tissue ablation per unit time which is but a fraction of a predetermined maximum ablation depth into the stroma of the cornea, and directing the laser beam at the anterior surface of the cornea in a controlled manner to create at least one excision in the anterior surface of the cornea relative to the optic axis thereof by volumetric removal of corneal tissue in the course of ablative photodecomposition of the stroma causing a redefinition of the anterior surface of the cornea.