USRE37504EExpiredUtility

Ophthalmic surgery method using non-contact scanning laser

Assignee: LASERSIGHT TECH INCPriority: Dec 3, 1992Filed: May 27, 1998Granted: Jan 8, 2002

Est. expiryDec 3, 2012(expired)· nominal 20-yr term from priority

A61B 2018/20359A61F 9/00821A61F 2009/00882A61F 9/008A61B 18/203B23K 26/0622A61F 2009/00897B23K 26/361A61F 9/00804A61F 2009/00872B23K 2103/50A61F 2009/00853B23K 2103/32

PatentIndex Score

141

Cited by

190

References

Claims

Abstract

A refractive laser surgery process is disclosed for using compact, low-cost ophthalmic laser systems which have computer-controlled scanning with a non-contact delivery device for both photo-ablation and photo-coagulation in corneal reshaping. The basic laser systems may include flash-lamp and diode pumped UV solid state lasers (193-215 nm), compact excimer laser (193 nm), free-running Er:glass (1.54 microns), Ho:YAG (2.1 microns), Q-switched Er:YAG (2.94 microns), and tunable IR lasers, (750-1100) nm and (2.5-3.2) microns. The advantages of the non-contact, scanning device used in the process over other prior art lasers include being safer, reduced cost, more compact and more precise and with greater flexibility. The theory of beam overlap and of ablation rate and coagulation patterns is also disclosed for system parameters. Lasers are selected with energy of (0.01-10) mJ, repetition rate of (1-10,000), pulse duration of 0.01 nanoseconds to a few hundreds of microseconds, and with spot size of (0.05-2) mm for use with refractive laser surgery.

Claims

exact text as granted — not AI-modified

I claim:

1. A method of performing corneal refractive surgery by reshaping a portion of a corneal surface comprising the steps of:
selecting a laser having a pulsed output beam of predetermined ultraviolet wavelength and having an energy level less than of no greater than 10 mJ/pulse;
selecting a scanning mechanism for scanning said selected laser output beam, said scanning mechanism including a galvanometer scanning mechanism for controlling said laser beam into an overlapping pattern of adjacent pulses;
coupling said laser beam to a scanning device for scanning said laser beam over a predetermined surface;
focusing said scanning laser beam onto a corneal surface to a predetermined generally fixed spot size;
aligning the center of the said scanning laser beam onto the corneal surface with a visible aiming beam;
controlling the scanning mechanism to deliver the scanning laser beam in a predetermined overlapping pattern onto a plurality of positions on the corneal surface to photoablate or photocoagulate corneal tissue; and
removing from 0.05 to 0.5 microns of corneal tissue per pulse overlapped to remove tissue to a desired depth, whereby a patient&#39;s vision is corrected by the reshaping of the corneal surface of the patient&#39;s eye using a low power laser.

2. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting a diode-pumped UV laser having an output wavelength between 193 and 220 nanometers, and energy per pulse of 0.01 to 5 mJ/pulse, a repetition rate of between 1 Hz and 10 KHz, and a pulse duration between 0.1 picoseconds to 50 nanoseconds and a focused spot size of (0.05-1.5) mm on the corneal surface.

3. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting a flash lamp pumped UV laser having an output wavelength between 193 and 220 nanometers, and energy per pulse of 0.1 to 10 mJ/pulse, a repetition rate of between 1 Hz and 10 KHz, and a pulse duration between 0.1 picoseconds to 50 nanoseconds and a focused spot size of (0.05-1.5) mm on the corneal surface.

4. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting an argon fluoride excimer laser having an output wavelength of 193 nanometers, energy per pulse of 0.5 to 10 mJ/pulse and a focused generally fixed spot size of between 0.2 to 2 mm on the corneal surface, and a repetition rate of between 1 to 1,000 Hz, and pulse duration of between 1 to 50 nanoseconds.

5. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting a free-running Ho:YAG laser having an output wavelength of about 2.1 microns at an average power of between 0.5-5 watts and a focused generally fixed spot size of between 0.1-1 mm.

6. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting a free-running Er:glass laser having an output wavelength of about 1.54 microns at an average power of between 0.5-5 watts with a focused generally fixed spot size of between 0.1-1 mm.

7. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting a free-running Er:glass laser having an output wavelength of between 1.9 to 2.5 microns at a power of between 0.5-5 watts and a focused generally fixed spot size of between 0.1-1 mm.

8. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting a Q-switched Er:YAG laser having an output wavelength of 2.94 microns, and a pulse duration of between 50 to 400 nanoseconds, with an energy per pulse of between 50-500 mJ and a repetition rate of between 1 and 200 Hz with a focused generally fixed spot size of between 0.2-2 mm.

9. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting an ultra-short pulsed laser having an output wavelength of between 750 to 1100 nanometers, energy per pulse of between 0.01 to 100 microjoules, and a repetition rate of between 0.01 to 100 MHz, and pulse duration of between 0.05-10 picoseconds and a focused generally fixed spot size of between 0.05-0.5 mm.

10. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of selecting a laser includes selecting an OPO mid-IR laser having an output of 2.5-3.2 microns, a pulse duration of between 1-40 nanoseconds and energy per pulse of between 0.1 to 10 mJ, and a repetition rate of between 10 and 5,000 Hz and a focused generally fixed spot size on the corneal surface of between 0.1-2 mm.

11. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of delivering said laser beam includes said focusing lens which is highly transparent to the said laser beam, said focusing lens having a focal length of (50-1500) mm for focusing the laser source onto a generally fixed spot size of 0.05-2 mm on a predetermined position on the corneal surface.

12. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning mechanism includes controlling said scanning to scan a pattern of radial aligned spots using a laser beam capable of photocoagulation corneal tissue.

13. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning mechanism includes controlling said scanning to scan a pattern of concentric generally fixed spots using a laser beam capable of photocoagulating corneal tissue.

14. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning device includes controlling said scanning to scan a pattern of generally fixed area ring spots using a laser beam capable of photocoagulating corneal tissues.

15. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning device includes controlling said scanning to scan a pattern of overlapping generally fixed ring spots using a laser beam capable of photoablating corneal tissue for myopic correction.

16. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning mechanism includes controlling said scanning to scan a pattern of overlapping generally fixed area spots using a laser beam capable of photoablating the corneal tissue for hyperopic correction.

17. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning mechanism includes controlling said scanning to scan a pattern of overlapping circles of fixed area using a laser beam capable of photoablating the corneal tissue for astigmatic correction.

18. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning mechanism includes controlling said scanning to scan a pattern of radial aligned slits of fixed area using a laser beam capable of photoablating corneal tissue for laser radial keratectomy.

19. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 18 wherein the step of scanning includes scanning a coated window having a predetermined coating to direct said laser beam therethrough and to photoablate the corneal surface to meet a predetermined profile for refractive corrections.

20. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 18 in which the step of scanning includes scanning through a coated window made of materials transparent to a UV laser having an output beam of (193-215) nm.

21. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 18 in which the step of scanning includes scanning through a coated window made of materials highly transparent to an IR laser having an output beam of (2.5-3.2) microns.

22. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 in which the step of controlling said scanning mechanism includes controlling said scanning which has a circular scanning pattern to deliver uniform laser energy over a coated window positioning near the corneal surface.

23. A method of performing corneal refractive surgery by reshaping a portion of the corneal surface in accordance with claim 1 including the step of scanning in a uniform scanned pattern with a spatial overlap of 50-80% and beam orientation whereby the initial beam profile uniformity is not critical.

24. An ophthalmic surgery apparatus, comprising:

a basic laser having an output laser beam of a fundamental ultraviolet wavelength within a range of 193 - 220 nm exiting from an output window of said basic laser, and an energy level exiting from said output window of said basic laser of less than about 10 mJ per pulse sufficient to remove from 0 . 05 to 0 . 5 microns of tissue per pulse; and

a computer - controlled scanning device coupled to said basic laser to scan said pulsed output laser beam, through known positions of an optical device moved by galvanometric forces, to cause a significant overlap of adjacent ablation spots of predetermined generally fixed size on a single ablation layer of said corneal surface to achieve a smooth ablation of corneal tissue.

25. The ophthalmic surgery apparatus according to claim 24 , wherein:

said pulses are overlapped in a range of 50 to 80 percent.

26. The ophthalmic surgery apparatus according to claim 24 , wherein:

said pulsed beam has a spot size on said corneal tissue of less than or equal to 2 mm.

27. The ophthalmic surgery apparatus according to claim 24 , wherein said scanning device comprises:

a mirrored surface.

28. The ophthalmic surgery apparatus according to claim 24 , wherein:

a repetition rate of said laser is synchronized with said scanning device.

29. The ophthalmic surgery apparatus according to claim 24 , wherein:
successive pulses of said pulsed beam are rotated through a linear - scan angle by said scanning device.

30. The ophthalmic surgery apparatus according to claim 24 , wherein said optical device comprises:

a motor.

31. The ophthalmic surgery apparatus according to claim 24 , wherein said optical device comprises:

a mirrored device.

32. The ophthalmic surgery apparatus according to claim 24 , wherein said optical device comprises:

a refractive device.

33. A method for performing ophthalmic surgery comprising:

providing a basic laser having a pulsed output laser beam of a fundamental ultraviolet wavelength within a range of 193 - 220 nm exiting from an output window of said basic laser, a repetition rate of 1 Hz to 1000 Hz, and an energy level exiting from said output window of said basic laser of no greater than 10 mJ per pulse;

focusing said pulsed laser beam onto corneal tissue to a predetermined generally fixed spot size;

scanning said pulsed laser beam, through known positions of an optical device moved by galvanometric forces, in a substantially overlapping pattern on said corneal tissue such that adjacent ablation spots on a single ablation layer of said corneal tissue significantly overlap one another; and

removing from 0 . 05 to 0 . 5 microns of corneal tissue per pulse.

34. The method for performing ophthalmic surgery according to claim 33 , wherein:

said substantially overlapping pattern is achieved using randomized scanning of said pulsed laser beam on said corneal tissue.

35. The method for performing ophthalmic surgery according to claim 34 , wherein:

said pulsed laser beam has a spot size on said corneal tissue of no greater than 1 mm.

36. The method for performing ophthalmic surgery according to claim 33 , wherein:

said pulsed laser beam has a spot size on said corneal tissue of no greater than 1 mm.

37. The method for performing ophthalmic surgery according to claim 33 , wherein:

pulses of said pulsed laser beam corresponding to adjacent ablation spots on said single ablation layer overlap one another by least 50 percent.

38. The method for performing ophthalmic surgery according to claim 33 , wherein:

said pulsed laser beam is scanned synchronously with said pulses of said pulsed laser beam.

39. The method for performing ophthalmic surgery according to claim 33 , wherein:

an area of corneal tissue 0 . 2 to 0 . 5 microns deep is removed per pulse of said pulsed laser beam.

40. The method for performing ophthalmic surgery according to claim 33 , wherein:

said pulsed laser beam is scanned in circular patterns.

41. The method for performing ophthalmic surgery according to claim 33 , wherein:

said pulsed laser beam is scanned in linear patterns.

42. The method for performing ophthalmic surgery according to claim 33 , wherein:

said scanning moves said optical device using a motor.

43. The method for performing ophthalmic surgery according to claim 33 , wherein said scanning comprises:

rotational movement of said optical device.

44. The method for performing ophthalmic surgery according to claim 33 , wherein said optical device comprises:

a mirrored device.

45. The method for performing ophthalmic surgery according to claim 33 , wherein said optical device comprises:

a refractive device.

46. The method for performing ophthalmic surgery according to claim 33 , wherein said scanning comprises:

translational movement of said optical device.

47. The method for performing ophthalmic surgery comprising:

providing a basic laser having a pulsed output laser beam of a fundamental ultraviolet wavelength within a range of 193 - 220 nm exiting from an output window of said basic laser, a repetition rate of at least 1 Hz to 1000 Hz, and an energy level exiting from said output window of said basic laser of 0 . 5 to 10 mJ per pulse;

focusing said pulsed output laser beam onto corneal tissue to a predetermined generally fixed spot size;

removing from 0 . 05 to 0 . 5 microns of corneal tissue per pulse.

48. The method for performing ophthalmic surgery according to claim 47 , wherein:

said pulsed laser beam has a spot size on said corneal tissue of no greater than 1 mm.

49. The method for performing ophthalmic surgery according to claim 47 , wherein:

pulses of said pulsed laser beam corresponding to adjacent ablation spots on said single ablation layer overlap one another by at least 50 percent.

50. The method for performing ophthalmic surgery according to claim 47 , wherein:

said pulsed laser beam is pulsed at a repetition rate of at least 50 Hz.

51. The method for performing ophthalmic surgery according to claim 47 , wherein:

said pulsed laser beam is scanned synchronously with said pulses of said pulsed laser beam.

52. The method for performing ophthalmic surgery according to claim 47 , wherein:

said pulsed laser beam is scanned in circular patterns.

53. The method for performing ophthalmic surgery according to claim 47 , wherein:

said pulsed laser beam is scanned in linear patterns.

54. A method of performing laser ablation on tissue, said method comprising:

providing a galvanometer scanner; and

significantly overlapping adjacent ablation spots focused to a predetermined generally fixed spot size on a single ablation layer of said tissue by controlling said pulsed output beam with said galvanometer scanner to provide a substantially overlapping pattern of beam pulses on said tissue which remove from 0 . 05 to 0 . 5 microns of tissue per pulse.

55. The method of performing laser ablation on tissue according to claim 54 , wherein:

said substantially overlapping pattern is achieved by placing said ablation spots on said single ablation layer of said tissue in random order.

56. The method of performing laser ablation on tissue according to claim 54 , wherein:

said pulse delivered at said tissue has an energy of 10 mJ per pulse or less.

57. The method of performing laser ablation on tissue according to claim 54 , wherein:

said ultraviolet wavelength is 193 nm.

58. The method of performing laser ablation on tissue according to claim 54 , wherein:

said pulsed output laser beam has an energy level exiting from said output window of said basic laser in a range of 0 . 05 to 10 mJ per pulse.

59. The method of performing laser ablation on tissue according to claim 58 , wherein:

said pulsed output beam has a spot size on said tissue of no greater than 1 mm.

60. The method of performing laser ablation on tissue according to claim 54 , wherein:

said pulsed output beam has a spot size on said tissue of no greater than 1 mm.

61. The method of performing laser ablation on tissue according to claim 54 , wherein:

pulses of said pulsed output beam corresponding to adjacent ablation spots on said single ablation layer overlap one another by at least 50 percent.

62. The method of performing laser ablation on tissue according to claim 54 , wherein:

said pulsed output beam is scanned synchronously with said pulses of said pulsed output beam.

63. The method of performing laser ablation on tissue according to claim 54 , wherein:

an area of corneal tissue in a range of 0 . 2 to 0 . 5 microns deep is removed per pulse of said pulsed output beam.

64. The method of performing laser ablation on tissue according to claim 54 , wherein:

said pulsed output beam is scanned in circular patterns.

65. The method of performing laser ablation on tissue according to claim 54 , wherein:

said pulsed output beam is scanned in linear patterns.

66. The method of performing laser ablation on tissue according to claim 54 , wherein:

said pulsed output beam is scanned in concentric circles.

67. The method of performing laser ablation on tissue according to claim 66 , wherein:

said concentric circles have increasing diameters.

68. A method for ablating tissue, comprising:

providing a basic laser having a pulsed output laser beam of a fundamental ultraviolet wavelength of 193 nm exiting from an output window of said basic laser, and a repetition rate of 1 Hz to 1000 Hz;

focusing said pulsed output laser beam onto said tissue to a predetermined generally fixed spot size; and

scanning said pulsed output laser beam, through known positions of an optical device moved by galvanometric forces, into a substantially overlapping pattern of beam pulses on said tissue such that adjacent ablation spots on a single ablation layer of said tissue significantly overlap one another and remove from 0 . 05 to 0 . 5 microns of tissue per pulse, whereby a laser pulse is delivered which is low power at said tissue.

69. The method for ablating tissue according to claim 68 , wherein:

an area of tissue 0 . 2 to 0 . 5 microns deep is removed per pulse of said pulsed laser beam.

70. The method for ablating tissue according to claim 68 , wherein:

said substantially overlapping pattern of beam pulses has an orientation which is achieved using a randomized scanning of said pulsed output beam on said tissue.

71. The method for ablating tissue according to claim 68 , wherein:

said pulsed output laser beam has an energy level exiting from said output window of said basic layer of no greater than 10 mJ per pulse.

72. The method for ablating tissue according to claim 68 , wherein:

said scanning overlaps adjacent beam pulses corresponding to adjacent ablation spots on said single ablation layer by at least 50 percent.

73. The method for ablating tissue according to claim 68 , wherein:

said basic layer is an excimer layer.

74. The method for ablating tissue according to claim 68 , wherein:

said scanning moves said optical device using a motor.

75. The method for ablating tissue according to claim 68 , wherein said scanning comprises:

rotational movement of said optical device.

76. The method for ablating tissue according to claim 68 , wherein said optical device comprises:

a mirrored device.

77. The method for ablating tissue according to claim 68 , wherein said optical device comprises:

a refractive device.

78. The method for ablating tissue according to claim 68 , wherein said scanning comprises:

translational movement of said optical device.

79. An ophthalmic surgery apparatus for performing corneal refractive surgery by reshaping a portion of a corneal surface, said apparatus comprising:

a basic laser having a pulsed output laser beam of a fundamental ultraviolet wavelength within a range of 193 - 220 nm exiting from an output window of said basic laser, and an energy level exiting from said output window of said basic laser of less than 10 mJ per pulse sufficient to remove from 0 . 05 to 0 . 5 microns of tissue per pulse; and

80. A method of performing corneal refractive surgery by reshaping a portion of corneal surface, said method comprising:

providing and pulsing a basic laser having an output laser beam of a fundamental ultraviolet wavelength within a range of 193 - 220 nm exiting from an output window of said basic laser, a repetition rate of 1 to 1000 pulses per second, and an energy level exiting from said output window of said basic laser of no greater than 10 mJ per pulse;

focusing said output laser beam onto a corneal surface in a predetermined fixed spot size;

scanning said output laser beam through known positions of an optical device moved by galvanometric forces; and

substantially overlapping adjacent ones of a plurality of ultraviolet laser beam pulses over a single ablation layer on said corneal surface sufficient to ablate a depth of between 0 . 05 and 0 . 5 microns of corneal tissue per ultraviolet laser beam pulse.

81. The method of performing corneal refractive surgery by reshaping a portion of a corneal surface according to claim 80 , further comprising:

selecting a scanner to scan said overlapping plurality of laser beam pulses, said scanner deflecting said laser beam pulses a predetermined angle.

82. The method of performing corneal refractive surgery by reshaping a portion of a corneal surface according to claim 81 , wherein:

said optical device includes a mirrored surface.

83. A method for performing corneal refractive surgery by reshaping a portion of corneal surface, comprising:

selecting a basic laser having a pulsed output laser beam of a fundamental ultraviolet wavelength within a range of 193 - 220 nm exiting from an output window of said basic laser, and an energy level exiting from said output window of said basic laser of less than 10 mJ/pulse;

selecting a scanning mechanism for scanning said pulsed output laser beam through known positions of an optical device moved by galvanometric forces;

coupling said pulsed output laser beam to said scanning mechanism for focusing said pulsed output laser beam in a predetermined generally fixed spot size on said corneal surface;

controlling said scanning mechanism to deliver said scanning pulsed output laser beam in a substantially overlapping pattern on said corneal surface such that adjacent ablation spots on a single ablation layer of said corneal tissue significantly overlap one another to at least one of photoablate and photocoagulate corneal tissue; and

removing from 0 . 05 to 0 . 5 microns of corneal tissue per pulse, whereby a patient&#39;s vision is corrected by said reshaping of said portion of said corneal surface of said patient&#39;s eye.

84. The method for performing corneal refractive surgery according to claim 83 , wherein said optical device comprises:

a mirrored surface.

85. The method for performing corneal refractive surgery according to claim 83 , further comprising:

aligning a center of said scanning laser beam onto said corneal surface with a visible aiming beam.

86. A method for performing ophthalmic surgery, comprising:

providing a basic laser having a pulsed output laser beam of a fundamental ultraviolet wavelength within a range of 193 - 220 nm exiting from an output window of said basic laser, and an output energy level exiting from said output window of said basic laser of no greater than 10 mJ/pulse sufficient to remove from 0 . 05 to 0 . 5 microns of corneal tissue per pulse;

focusing said pulsing ultraviolet laser beam into a predetermined generally fixed spot size on corneal tissue; and

scanning said pulsing laser beam, through known positions of an optical device moved by galvanometric forces, in a purposefully substantially overlapping pattern on said corneal tissue such that adjacent ablation spots in said overlapping pattern on a single ablation layer of said corneal tissue significantly overlap one another.

87. The method of performing ophthalmic surgery according to claim 86 , wherein:

said pulsing ultraviolet laser beam is pulsed at a repetition of 1 to 1000 Hz.

88. The method of performing ophthalmic surgery according to claim 86 , wherein:

said pulsing ultraviolet laser beam is sufficient to ablate a depth in a range of 0 . 2 and 0 . 5 microns of corneal tissue per pulse.

89. The method for performing ophthalmic surgery according to claim 86 , wherein:

said substantially overlapping pattern is achieved using a randomized scanning of said pulsed laser beam on said corneal tissue.

90. The method of performing ophthalmic surgery according to claim 86 , wherein:

pulses of said ultraviolet laser beam corresponding to adjacent ablation spots on said single ablation layer overlap one another by at least 50 percent.

91. The method of performing ophthalmic surgery according to claim 86 , wherein:

pulses of said ultraviolet laser beam corresponding to adjacent ablation spots on said single ablation layer overlap one another in a range of 50 to 80 percent.

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