Method for collagen treatment

• US 4,976,709 A
• Filed: 06/30/1989
• Issued: 12/11/1990
• Est. Priority Date: 12/15/1988
• Status: Expired due to Term

• Current Assignee: 21X Capital Ltd.
• Original Assignee: Bruce J. Sand
• Inventors: Sand, Bruce J.
• Primary Examiner(s): Hindenburg, Max
• Application Number:
  US07/374,958
• Time in Patent Office: 529 Days
• Field of Search: 128/6, 128/395-398, 372/41, 606/3-5
• US Class Current: 606/5
• CPC Class Codes: A61F 2009/00853 Laser thermal keratoplasty or radial keratotomy
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 9/008 using laser

Abstract

A method for controlled thermal shrinkage of collagen tissue by irradiation with coherent energy in the wavelength band of 1.80 to 2.55 microns as generated by a laser. A specific application to ophthalmological corneal reshaping is described.

Claims

1. A method for shrinking collagen tissue comprising the step of irradiating the tissue with energy having a wavelength in the range of about 1.80 to 2.55 microns.

2. The method defined in claim 1 wherein the energy is delivered as a pulse with a duration in the range of about 0.01 to 1.0 second.

3. The method defined in claim 2 wherein the pulse has a duration of about 0.1 seconds.

4. The method defined in claim 1 wherein the energy is focused to produce an energy density in the tissue of up to 100 joules per square centimeter.

5. The method defined in claim 1 wherein the energy is focused to a spot with a diameter in the range of 0.25 to 2.0 millimeters.

6. The method defined in claim wherein the energy wavelength is in the range of about 2.0 to 2.2 microns.

7. A keratoplasty method for shape modification of a cornea comprising the step of irradiating the cornea with energy having a wavelength in the range of about 1.80 to 2.55 microns to shrink collagen tissue in the cornea.

8. The method defined in claim 7 and further comprising the step of cooling an anterior surface of the cornea during irradiation.

9. The method defined in claim 8 wherein the energy is delivered as a pulse with a duration in the range of about 0.01 to 1.0 second.

10. The method defined in claim 8 wherein the pulse has a duration of about 0.1 seconds.

11. The method defined in claim 8 wherein the energy is focused to produce an energy density in the tissue of up to 100 joules per square centimeter.

12. The method defined in claim 11 wherein the energy is focused to a spot with a diameter in the range of 0.25 to 2.0 millimeters.

13. The method defined in claim 12 wherein the energy wavelength is in the range of about 2.0 to 2.2 microns.

14. The method defined in claim 13 wherein said irradiating step is repeated to produce multiple zones of collagen shrinkage to effect an overall corneal shape change which corrects a refractive error.

15. A keratoplasty method for shape modification of a cornea, comprising the step of irradiating the cornea with coherent laser energy of infrared wavelength corresponding to corneal-collagen absorption coefficients in the range of about 15 to 120 cm^-1, and thereby to heat and shrink the corneal collagen.

16. The method defined in claim 15 wherein the energy is applied as at least one energy pulse with a duration in the range of about 0.01 to 1.0 second.

17. The method defined in claim 15 wherein the energy is applied to produce an energy density of up to 100 joules per square centimeter in a stromal region of the cornea.

18. The method defined in claim 17 wherein the energy wavelength is in the range of 1.80 to 2.55 microns.

19. The method defined in claim 18 wherein the irradiating step is repeated to produce multiple zones of collagen shrinkage to effect an overall corneal shape change which corrects a refractive error.

20. The method defined in claim 19 wherein the energy wavelength is in the range of about 2.0 to 2.2 microns, the pulse duration is about 0.1 seconds, and the energy is focused to a spot size in the range of about 0.25 to 2 millimeters.

21. The method of claim 19 wherein each zone is subjected to multiple pulse applications of energy.