Automated laser workstation for high precision surgical and industrial interventions

• US 6,099,522 A
• Filed: 09/05/1995
• Issued: 08/08/2000
• Est. Priority Date: 02/06/1989
• Status: Expired due to Fees

• Current Assignee: Amo Manufacturing Usa, Llc (Johnson & Johnson)
• Original Assignee: VISX Incorporated
• Inventors: Orkiszewski, Jerzy, Knopp, Carl F., Sklar, H. Alfred, Fountain, William D., Persiantsev, Michael, Wysopal, Jan
• Primary Examiner(s): Shay, David M.
• Application Number:
  US08/523,738
• Time in Patent Office: 1,799 Days
• Field of Search: 606/2-6, 606/10-18, 607/88-92, 351/206, 351/208-212, 356/4, 356/4.5, 356/72, 356/372-373, 356/375, 356/379-385, 219/121.6-121.73, 219/121.78-121.83, 219/121.85, 219/121.86
• US Class Current: 606/10
• CPC Class Codes: A61B 2017/00199 with a console, e.g. a control panel with a display
• CPC Class Codes: A61B 2017/00694 with means correcting for movement of or for synchronisation with the body
• CPC Class Codes: A61B 2017/00973 pedal-operated
• CPC Class Codes: A61B 3/13 Ophthalmic microscopes
• CPC Class Codes: A61F 2009/0035 Devices for immobilising a patient's head with respect to the instrument
• CPC Class Codes: A61F 2009/00846 Eyetracking
• CPC Class Codes: A61F 2009/00863 Retina
• CPC Class Codes: A61F 2009/00868 Ciliary muscles or trabecular meshwork
• CPC Class Codes: A61F 2009/0087 Lens
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 2009/00876 Iris
• CPC Class Codes: A61F 2009/00882 based on topography
• CPC Class Codes: A61F 2009/00889 Capsulotomy
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61F 9/00802 for photoablation
• CPC Class Codes: A61F 9/00804 Refractive treatments
• CPC Class Codes: A61F 9/00821 for coagulation
• CPC Class Codes: A61F 9/00825 for photodisruption
• CPC Class Codes: B23K 26/0096 Portable laser equipment, e.g. hand-held laser apparatus surgical laser instruments A61B18/20, Dental Lasers A61C1/0046, Hand-held laser dental apparatus for curing resins A61C19/004
• CPC Class Codes: B23K 26/04 Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light

Abstract

A method, apparatus and system for template-controlled, precision laser interventions is described that greatly improves the accuracy, speed, range, reliability, versatility, safety, and efficacy of interventions such as laser microsurgery, particularly ophthalmic surgery, and industrial micromachining. The instrument and system are applicable to those specialties wherein the positioning accuracy of laser lesions is critical, wherever accurate containment of the spatial extent of a laser lesion is desirable, and/or whenever precise operations on a target or series of targets subject to movement during the procedure are to be effected. The system thus comprises the following key elements: (1) a user interface, consisting of a video display, microprocessor and controls, (2) an imaging system, which may include a surgical video microscope with zoom capability, (3) an automated 3D target acquisition and tracking system that can follow the movements of the subject tissue, for example an eye, during the operation, thus allowing the surgeon/user to predetermine his firing patern based on an image which is automatically stabilized over time, (4) a laser, with which can be focused so that only the precise lesions described by the user interface are effected, (5) a diagnostic system, incorporating a mapping and topography means for measuring precise surface shapes prior to and subsequent to a procedure, said measurements to be executed on-line within time scales not limited to human response times, and (6) a fast reliable safety means, whereby the laser firing is interrupted automatically, should any conditions arise to warrant such interruption of the procedure.

Claims

1. A laser workstation for precision ophthalmic surgery at a surgery site in a patient'"'"'s eye tissue, comprising:

therapeutic laser means for generating a short pulse laser beam capable of effecting photodisruption of the patient'"'"'s eye tissue so as to effect desired surgery by sequences of pulses traversing through a surgical path in the eye tissue, including within transparent tissue of the patient'"'"'s eye,

user interface means including control means for enabling a surgeon to select and initiate a pattern of surgery in the eye tissue of the patient, and including high resolution video imaging means for presenting live, magnified video images of the surgery site to the surgeon on a video monitor,

a laser beam delivery system including

(a) optical path means for receiving the short pulse laser beam and for aiming the beam at a point in X-Y directions and focussing the beam at a depth as desired toward a target in the patient'"'"'s eye, including a front lens element from which the beam exits the optical path means toward the patient,

(b) beam steering means connected to the optical path means for controlling the position at which the beam is aimed in X-Y directions,

(c) beam focussing means connected to the optical path means for controlling the depth at which the laser beam is focussed,

tracking means for tracking eye movements of the patient during the progress of the surgery, including X-Y tracking means for tracking a feature of the eye in X and Y directions, and depth or Z tracking means for tracking depth movements of the eye'"'"'s feature, toward and away from the workstation,

microprocessor means connected to the tracking means for automatically shifting the optical path means as the feature of the eye is tracked through X-Y and Z movements, so as to change the aim and focus of the laser beam when necessary to follow such movements of the eye, and

safety interrupt means associated with the microprocessor means for interrupting delivery of the laser beam to the patient when it is determined via the microprocessor means that the tracking means has lost the feature being tracked.

2. A laser workstation according to claim 1, further including laser energy monitoring means for sampling the laser beam from the optical path means, and for feeding a signal representing the laser beam'"'"'s energy magnitude to the microprocessor means, and the safety interrupt means further including means for interrupting delivery of the laser beam when the signal from the laser energy monitoring means indicate that energy is above or below a prescribed range.

3. A laser workstation according to claim 1, further including parallax depth ranging means connected into the optical path means, for tracking the depth of the eye'"'"'s feature in a broader range of depth than the Z tracking means, the parallax depth ranging means being connected to the microprocessor means and being effective to assist in focussing the treatment beam to structure below the transparent cornea.

4. A laser workstation according to claim 1, wherein the eye has a limbus, and the X-Y tracking means includes means for tracking the limbus of the eye.

5. A laser workstation according to claim 1, further including template means under the control of the user for generating and implementing a preprogrammed template or path of successive laser photodisruption points across the patient'"'"'s eye tissue, and for automatically carrying out the template-controlled surgery without active participation by the user during the surgery.

6. A laser workstation according to claim 1, wherein the Z tracking means comprises a separate tracking subassembly from the X-Y tracking means, both being folded onto the optical path means.

7. A laser workstation according to claim 6, wherein the Z-tracking means includes means for maintaining essentially constant distance between the front lens element and the targeted eye tissue.

8. A laser workstation according to claim 4, wherein the eye has a limbus, and the X-Y tracking means comprises means for tracking the limbus of the eye.

9. A laser workstation according to claim 1, wherein the video imaging means and the microprocessor means include means for displaying an indicated laser aim point on the live video images on the video monitor, superimposed on the surgery site in the patient'"'"'s eye tissue.

10. A laser workstation according to claim 9, further including means for displaying on the video monitor a depth or Z position of the laser aiming point in the patient'"'"'s eye tissue.

11. A laser workstation according to claim 1, further including template means for enabling the user to draw, adjust or designate a particular template pattern of preprogrammed surgery, as overlaid on video images of the patient'"'"'s eye tissue displayed on the video monitor.

12. A laser workstation according to claim 11, wherein the template means includes means for converting a template pattern into a sequence of automatic motion instructions to direct a laser beam to focus sequentially on a number of points in three-dimensional space which will, in turn, replicate the designated template pattern onto the surgery site.

13. A laser workstation according to claim 1, wherein the high resolution video imaging means is coaxial with the laser beam through the front lens element of the optical path means and includes zooming means for enabling selectable variable magnification of the video image on the video monitor.

14. A laser workstation according to claim 13, wherein the zooming means includes means for providing variable magnification up to 250 times.

15. A laser workstation according to claim 13, wherein the high resolution video imaging means has a resolution of better than five microns.

16. A laser workstation according to claim 1, further including ocular topographic mapping means connected into the optical path means, for determining surface shapes of the eye and for displaying such shapes and data regarding such shapes on the video monitor.

17. A laser workstation according to claim 16, wherein the eye has a cornea with an epithelium, and endothelium, and a thickness, and the ocular topographic mapping means includes means for determining topographical shapes of at least the epithelium and the endothelium of the cornea, as well as the thickness of the cornea between the epithelium and the endothelium.

18. A laser workstation according to claim 17, wherein the ocular topographic mapping means further includes means for determining topographical shapes of the ocular lens.

19. A laser workstation according to claim 16, wherein the ocular topographic mapping means includes means acting in combination with the microprocessor means for displaying on the video monitor a video image of a contour elevation map of a surface of the eye, in different selectable perspectives.

20. A laser workstation according to claim 19, wherein the topographic mapping means and the microprocessor means further include numerical display means for displaying on the video monitor diagnostic data pertaining to shapes of surfaces of the eye.

21. A laser workstation according to claim 19, further including superimposing means associated with the video monitor and the microprocessor means for enabling the surgeon to superimpose a pattern of proposed surgery on the video image of the contour elevation map.

22. A method for conducting precision ophthalmic surgery at a surgery site on or in a patient'"'"'s eye tissue, comprising:

generating a short pulse laser beam capable of effecting photodisruption of the patient'"'"'s eye tissue so as to effect desired surgery by sequences of pulses traversing through a surgical path in the eye tissue, including within transparent tissue of the patient'"'"'s eye,

providing a user interface control means for enabling a surgeon to select and initiate a pattern of surgery in the eye tissue of the patient,

presenting live, high resolution, magnified video images of the surgery site to the surgeon on a video monitor, using a high resolution video imaging means,

with a laser beam delivery system, performing the steps of

(a) receiving the short pulse laser beam and aiming the beam at a point in X-Y directions and focussing the beam at a depth with optical means and when appropriate toward a target in the patient'"'"'s eye, through a front lens element,

(b) controlling the position at which the beam is aimed in X-Y directions, using a beam steering means connected to the optical means,

(c) controlling the depth at which the laser beam is focussed, with a beam focussing means connected to the optical means,

tracking eye movements of the patient during the progress of the surgery, in X and Y directions, with an X-Y tracking means for tracking a feature of the eye, and as to depth movements of the eye with a depth or Z tracking means,

automatically shifting the optical path means as the feature of the eye is tracked through X-Y and Z movements, so as to change the aim and focus of the laser beam when necessary to follow such movements of the eye, with the aid of a microprocessor connected to the tracking means, and

automatically interrupting delivery of the laser beam to the patient when it is determined via the microprocessor that the tracking means has lost the feature being tracked.

23. The method of claim 22, further including tracking the depth of the eye'"'"'s feature in a broader range of depth than the Z tracking means with a parallax depth ranging means, the parallax depth ranging means being connected to the microprocessor means, and using the parallax depth ranging means to assist in focussing the treatment beam to structure below the transparent cornea.

24. The method of claim 22, including maintaining essentially constant distance between the front lens element and the targeted eye tissue using the Z-tracking means.

25. The method of claim 22, wherein the step of tracking eye movements in X and Y directions comprises tracking the limbus of the eye.

26. The method of claim 22, including automatically displaying an indicated laser aim point on the live video image, superimposed on the surgery site in the patient'"'"'s eye tissue on the video monitor, using the microprocessor and the video imaging means.

27. The method of claim 26, further including automatically displaying on the video monitor a depth or Z position of the laser aiming point in the patient'"'"'s eye tissue.

28. The method of claim 22, wherein the ophthalmic surgery site is the patient'"'"'s cornea, the desired pattern of surgery being a pattern of corneal refractive surgery.

29. The method of claim 28, wherein the laser beam is focussed below the anterior surface of the cornea to make a desired pattern of incisions to effect optical correction of deficiencies by creating a precise lesion within the stroma.

30. The method of claim 22, further including determining surface shapes of the eye automatically using an ocular topographic mapping means connected to the optical path means and displaying such shapes and data regarding such shapes on the video monitor.

31. The method of claim 30, including determining topographical shapes of at least the epithelium and the endothelium of the cornea, as well as the thickness of the cornea between the epithelium and the endothelium.

32. The method of claim 30, including displaying on the video monitor a contour elevation map of a surface of the eye, in different selectable perspectives, using the ocular topographical mapping means in cooperation with the microprocessor.

33. The method of claim 32, further including displaying on the monitor relevant numerical diagnostic data pertaining to shapes of surfaces of the eye, using topographic mapping means and the microprocessor.

34. The method of claim 32, further including, under the control of the surgeon, superimposing a pattern of proposed surgery on the video image of the contour elevation map on the video monitor.

35. The method of claim 22, further including monitoring substantially continuously the laser beam from the optical means, and feeding a signal representing the energy magnitude to the microprocessor, and automatically interrupting delivery of the laser beam when the signals from laser energy monitoring indicate that energy is above or below a prescribed range.

36. The method of claim 35, wherein the laser beam is focussed into the lens of the eye for modification to effect precise lesions for the prevention of presbyopia.

37. The method of claim 36, further including tracking the depth of the eye'"'"'s feature in a broader range of depth than the Z-tracking means with a parallax depth ranging means, the parallel depth ranging means being connected to the microprocessor means, and using the parallax depth ranging means to assist in focusing the treatment beam to structure below the transparent cornea.

38. The method of claim 36, wherein the wavelength of the laser beam is in the range of about 450 to 900 nanometers.

39. The method of claim 35 wherein the laser beam is focused onto the retina of the eye to treat retinal membranes or to perform photocoagulation to correct or prevent macular degeneration or to perform pan-retinal photocoagulation.

40. The method of claim 39, wherein the laser beam has a pulse repetition rate of at least about 200 pps, each of the laser pulses having less than about two millijoules energy per pulse in a near-diffraction limited beam, i.e. a beam having energy of about 1.5 to 2.5 times diffraction limit energy.

41. The method of claim 40, wherein the laser has a wavelength between about 450 and 650 nanometers.

42. The method of claim 35, wherein the pulsed laser beam is generated at a repetition rate of at least about 200 pulses per second, with each pulse having less than two millijoules energy in a near-diffraction-limited beam, each pulse having a duration between about one and twenty nanoseconds, and wherein the laser beam is focussed to a spot size of less than five microns.

43. The method of claim 42, wherein the laser beam is pulsed at a repetition of over 1000 pps and focussed onto the lens of the eye, the pattern of surgery being such as to remove cataracts from the lens.

44. The method of claim 42, wherein the laser beam is focussed on the posterior capsule of the eye, the pattern of surgery being such as to effect capsulotomy.

45. The method of claim 42, including focussing the laser beam onto Schlemm'"'"'s canal of the eye, to perform trabeculoplasty.

46. The method of claim 42, wherein the laser beam is focussed into the sclera of the eye, to perform sclerectomy.

47. The method of claim 46, wherein the step of tracking eye movements in X and Y directions comprises tracking the limbus of the eye.

48. The method of claim 42, wherein the laser beam is focussed into the iris of the eye, to perform iridectomy.

49. The method of claim 48, wherein the step of tracking eye movements in X and Y directions comprises tracking the limbus of the eye.

50. The method of claim 48, further including determining surface shapes of the eye automatically using an ocular topographic mapping means connected to the optical path means and displaying such shapes and data regarding such shapes on the video monitor.

51. The method of claim 42, wherein the laser beam is focussed below the anterior surface of the cornea, and including the steps of making incisions to effect optical corrections of deficiencies such as myopia, hyperopia or astigmatism, through the creation of a precise lesion within the stroma.

52. The method of claim 51, including maintaining essentially constant distance between the front lens element and the targeted eye tissue using the Z-tracking means.

53. The method of claim 51, wherein the step of tracking eye movements in X and Y directions comprises tracking the limbus of the eye.

54. The method of claim 35, further including, under the control of the surgeon, drawing, adjusting or designating a particular template pattern of pre-programmed surgery, as overlaid on video images of the patient'"'"'s eye tissue displayed on the video monitor.

55. The method of claim 51, wherein the wavelength of the laser beam is maintained in a range between about 450 and 900 nanometers, thereby permitting reasonably good transmission through the cornea.

56. The method of claim 55, wherein the wavelength of the laser beam is approximately 532 nanometers.

57. The method of claim 51, further including determining surface shapes of the eye automatically using an ocular topographic mapping means connected to the optical path means and displaying such shapes and data regarding such shapes on the video monitor.

58. The method of claim 57, including determining topographical shapes of at least the epithelium and the endothelium of the cornea, as well as the thickness of the cornea between the epithelium and the endothelium.

59. The method of claim 57, including displaying on the video monitor a contour elevation map of a surface of the eye, in different selectable perspectives, using the ocular topographic mapping means in cooperation with the microprocessor.

60. The method of claim 59, further including, under the control of the surgeon, superimposing a pattern of proposed surgery on the video image of the contour elevation map on the video monitor.

61. A laser workstation for precision laser interventions on a work site target at a work site, for carrying out a precision operation directed by a user, the workstation comprising:

a laser generating a pulsed laser beam capable of effecting a desired type of intervention on the work site so as to effect the operation on or in the work site by sequences of pulses traversing an optical path,

a user interface coupled to the laser, the user interface including a control input enabling the user to initiate a pattern of interventions at the work site, and including an imaging system presenting images of the work site to the user,

a laser beam delivery system including;

(a) an optical train in the optical path of the beam, the optical train aiming the beam at a point in X-Y directions as desired toward a work site target according to the pattern and including a front element from which the beam is transmitted toward the work site,

(b) a beam steering mechanism coupled to the optical path so as to control the position at which the beam is aimed in X-Y directions,

a template controller in communication with the beam steering mechanism so as to define the pattern of successive laser interventions across the work site as overlaid on magnified images of the work site, and for automatically carrying out the template-controlled interventions without active participation by the user during the operation, the template controller including a library of stored preprogrammed templates and configured to, in response to input from the user, select a template from the template library, scale the template, and situate the template relative to the worksite,

a tracking system generating signals in response to movements of the work site during the progress of the operation, the tracking system including an X-Y tracker for tracking a feature of the worksite in X and Y directions,

a processor coupling the tracking system to the beam steering mechanism so as to automatically shift the optical path as the feature of the work site is tracked through X-Y movements, and so as to change the aim of the laser beam to follow such movements of the feature, and

an interrupt circuit coupled to the microprocessor, the interrupt circuit interrupting delivery of the laser beam to the work site when it is determined via the microprocessor that the tracking system has lost the feature being tracked.

62. A laser workstation for precision laser interventions on a work site target, for carrying out a precision operation, comprising:

laser means for generating a short pulse laser beam capable of effecting a desired type of intervention on the work site so as to effect the operation by sequences of pulses traversing through a path on or in the work site,

user interface means including control means for enabling a user to select and initiate a pattern of interventions at the work site, and including video imaging means with a video monitor, for presenting video images of the work site to the user,

a laser beam delivery system including

(a) optical path means for receiving the short pulse laser beam and for aiming the beam at a point in X-Y directions and focussing the beam at a depth as desired toward a work site target including a front lens element from which the beam exits the optical path means toward the worksite,

(b) beam steering means connected to the optical path means for controlling the position at which the beam is aimed in X-Y directions,

(c) beam focussing means connected to the optical path means for controlling the depth at which the laser beam is focussed,

template means controlled by the user for generating and implementing a template or path of successive laser interventions across the work site as overlaid on magnified video images of the work site displayed on the video monitor, and for automatically carrying out the template-controlled interventions without active participation by the user during the operation,

tracking means for tracking movements of the work site during the progress of the operation, including X-Y tracking means for tracking a feature of the worksite in X and Y directions,

microprocessor means connected to the tracking means for automatically shifting the optical path means as the feature of the work site is tracked through X-Y movements, so as to change the aim of the laser beam when necessary to follow such movements of the feature, and

interrupt means associated with the microprocessor means for interrupting delivery of the laser beam to the work site when it is determined via the microprocessor means that the tracking means has lost the feature being tracked.

63. A laser workstation according to claim 62, wherein the template means includes means for enabling selection of a template from a library of stored preprogrammed templates, as said means for generating a template.

64. A laser workstation according to claim 62, further including means for displaying on the video monitor a depth or Z position of the laser aiming point in the worksite target.

65. A laser workstation according to claim 62, wherein the template means includes means for converting a template pattern into a sequence of automatic motion instructions to direct a laser beam to focus sequentially on a number of points in three-dimensional space which will, in turn, replicate the designated template pattern onto the work site.

66. A laser workstation according to claim 62, wherein the laser means generates a beam of visible laser light.

67. A laser workstation according to claim 62, wherein the laser means generates a laser beam having a wavelength of about 532 nanometers.

68. A laser workstation according to claim 62, wherein the laser means generates a laser beam having a wavelength and sufficient power density and fluence to effect photoablation on the exterior surface of the work site.

69. A laser workstation according to claim 62, wherein the laser means generates a laser beam having a wavelength and sufficient power density and fluence to effect photodisruption with each pulse within the work site, under a transparent outer surface of the work site.

70. A laser workstation according to claim 62, further including depth or Z-tracking means with means for positioning and maintaining essentially constant distance between the front lens element and the feature of the workpiece.

71. A laser workstation according to claim 70, wherein the means for positioning and maintaining has a resolution within one micron.

72. A laser workstation according to claim 70, further including parallax depth ranging means connected into the optical path means, for tracking the depth of the work site in a broader range of depth than the Z-tracking means, the parallax depth ranging means being connected to the microprocessor means and being effective to assist in focusing the treatment beam to structure below a transparent outer surface of the work site.

73. A laser workstation according to claim 62, wherein the video imaging means is coaxial with the laser beam through the front lens element of the optical path means and includes zooming means for enabling selectable variable magnification of the video image on the video monitor.

74. A laser workstation according to claim 73, wherein the zooming means includes means for providing variable magnification of the worksite target up to 250 times.

75. A laser workstation according to claim 74, wherein the resolution of the video imaging means is at least within five microns.

76. A laser workstation according to claim 62, wherein the laser means generates a laser beam having a wavelength in the ultraviolet range.

77. A laser workstation according to claim 76, wherein the laser means generates a beam having a wavelength of about 177 nanometers.

78. A laser workstation according to claim 76, wherein the laser means generates a laser beam having a wavelength of about 215 nanometers.

79. A laser workstation according to claim 76, wherein the laser means generates a laser beam having a wavelength of about 266 nanometers.

80. A laser workstation according to claim 76, wherein the laser means generates a laser beam having a wavelength of about 355 nanometers.