ADAPTIVE LASER SYSTEM FOR OPHTHALMIC USE

• US 20140058367A1
• Filed: 09/24/2013
• Published: 02/27/2014
• Est. Priority Date: 03/25/2011
• Status: Active Grant

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Dantus, Marcos
• Granted Patent: US 10,130,511 B2
• Time in Patent Office: Days
• US Class Current: 606/6
• CPC Class Codes: A61F 2009/00846 Eyetracking
• CPC Class Codes: A61F 2009/00863 Retina
• CPC Class Codes: A61F 2009/0087 Lens
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 9/00802 for photoablation
• CPC Class Codes: A61F 9/00827 Refractive correction, e.g. lenticle
• CPC Class Codes: A61F 9/00831 Transplantation
• CPC Class Codes: A61F 9/00836 Flap cutting
• CPC Class Codes: G02B 2207/114 Two photon or multiphoton effect
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0092 Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity nonlinear frequency conversion per se G02F1/35
• CPC Class Codes: H01S 3/06733 Fibre having more than one cladding
• CPC Class Codes: H01S 3/1112 Passive mode locking
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/1675 titanate, germanate, molybdate, tungstate

Abstract

An adaptive laser system for ophthalmic use is provided. In another aspect, a relatively inexpensive laser is employed. In another aspect of the present system, non-linear optical imaging uses multiphoton fluorescences and/or second harmonic generation, to create three-dimensional mapping of a portion of the eye in combination with automated feedback to assist with a surgical operation. In a further aspect of the present system, the patient interface uses laser induced markings or indicia to aid in focusing and/or calibration. Still another aspect employs temporal focusing of the laser beam pulse.

Claims

1. An ophthalmic surgical laser system comprising:

an ophthalmic laser emitting at least one unamplified laser pulse, each having a duration less than 150 fs with an output less than 2 μ

J and a repetition rate greater than 0.5 MHz, the ophthalmic laser being one of;

a direct diode pumped laser, and a Yb doped gain medium laser; and

at least one optic changing a characteristic of the pulse between the ophthalmic laser and a target focal point;

the at least one optic further comprising at least one of;

(a) a pulse shaper which assists in correcting nonlinear spectral phase distortions in the pulse to reduce undesired bubbles otherwise created by surgical ophthalmical use of the pulse; and

(b) a diffraction optic for diffracting colors in the pulse, a collimating optic for collimating the colors in the pulse and a focusing optic focusing the colors in the pulse at the target focal point at a desired spectral focusing depth.

2. The laser system of claim 1, wherein the optic is the pulse shaper, further comprising a programmable controller varying the pulse shaper in an automated and real-time manner to optimize desired performance through varying a temporal characteristic of the pulse.

3. The laser system of claim 1, wherein the at least one optic is the diffraction, collimating and focusing optics, the diffraction optic is a grating and focusing optic is a curved mirror, further comprising a computer controlled actuator operably moving the mirror to vary the desired spectral focusing depth.

4. The laser system of claim 1, further comprising an objective lens for focusing the pulse at the target focal point to create an indicating ophthalmic mark to aid in at least one of focusing and calibration during a subsequent ophthalmic procedure.

5. The laser system of claim 1, further comprising a portion of an eye is cut by the pulse, the target focal point being located in or on the eye.

6. The laser system of claim 1, wherein the ophthalmic laser is adapted to act on an eye for at least three operations selected from the following:

refractive correction, cutting corneal flaps, treatment of macular degeneration, corneal grafting, phaco chopping, lens extraction, photo bleaching, presbiopia correction, and fundus imaging.

7. The laser system of claim 1, further comprising at least a second ophthalmic laser emitting at least one unamplified laser pulse, each of the lasers having a duration less than 80 fs with an output less than 0.5 μ

J and a repetition rate greater than 5 MHz, the lasers being of a modularized construction and mounted to a single ophthalmic surgical machine such that laser emission can be easily interchanged for one another almost instantaneously.

8. The laser system of claim 1, further comprising a programmable controller using software which automatically measures nonlinear optical distortions in the laser pulse in less than one minute and compresses the pulses by pre-compensating dispersion.

9. The laser system of claim 1, further comprising:

a detector connected to a programmable controller;

the at least one laser pulse scanning across a portion of an eye and the detector collecting a nonlinear optical signal based on the laser pulse scan;

the laser, detector and controller causing nonlinear optical imaging of the portion of the eye instead of using optical coherent tomography to create a three dimensional map to assist in guiding subsequent eye surgery tailored to that specific eye using subsequent laser pulses.

10. The laser system of claim 1, wherein the target focal point coincides with an eye lens which is cut in a contiguous pattern by the at least one laser pulse such that the eye lens is removable as a single piece and replaced by an intraocular lens.

11. The laser system of claim 1, wherein fiber and free space elements are combined to generate a laser pulse bandwidth greater than 60 nm.

12. The laser system of claim 1, further comprising nonlinear polarization provides mode locking, and an intracavity spectral filter is associated with the laser.

13. The laser system of claim 1, further comprising a compact free space oscillator produces the pulses longer than 100 fs, followed by a fiber whose self-phase modulation causes sufficient bandwidth to compress the pulses to durations shorter than 50 fs.

14. The laser system of claim 1, wherein the at least one optic includes a pulse shaper which causes each of the pulses to separate into a train of at least two pulses.

15. The laser system of claim 1, wherein the at least one optic further comprises an objective lens having an aperture that is operable to limit a numerical aperture in order to change a length over which the laser alters tissue of an eye.

16. The laser system of claim 1, wherein the laser is a sub-30 fs titanium:

sapphire laser with a repetition rate greater than 1 MHz and a pulse energy less than 20 nJ.

17. The laser system of claim 1, wherein a portion of the at least one pulse is reflected to a set of optics that replicates a dispersion of an objective, eye piece and eye, and provides real-time information about a quality of the at least one pulse being delivered to the eye.

18. The laser system of claim 1, further comprising gold nanoparticles located in or on an eye, and the at least one pulse being emitted at the gold nanoparticles to assist in an ophthalmic surgery.

19. The laser system of claim 1, wherein the at least one pulse is transmitted through epithelial cells to selectively image and/or treat different layers of a macula lutea or ganglion cells.

20. An ophthalmic surgical laser system comprising:

an ophthalmic laser emitting at least one laser pulse, each having a duration less than 150 fs;

a diffracting optic operably diffracting colors in the pulse;

a collimating optic operably collimating the colors in the pulse;

a focusing optic focusing the colors in the pulse at a target focal point; and

a programmable controller operably causing the target focal point to be at a desired spectral focusing eye depth to allow for laser eye surgery at the desired spectral focusing eye depth but without affecting the adjacent areas subject to the unfocused laser pulse.

21. The laser system of claim 20, wherein the diffracting optic is a grating, the collimating optic is another grating and the focusing optic is an objective lens.

22. The laser system of claim 20, wherein the pulse duration is less than or equal to 50 fs, and self focusing of the laser pulse is deterred.

23. The laser system of claim 20, wherein the optics and controller cause all of the frequencies of the laser pulse to overlap in space and time at the target focal point while maximum peak intensity is achieved.

24. The laser system of claim 20, further comprising a detector connected to the controller operably receiving laser induced non-linear signals from a position of the laser focus in order to create a three dimensional map of a portion of an eye acted upon by the scanning laser pulse, the controller using the three dimensional map to assist in determining the subsequent target focal point for eye surgery.

25. The laser system of claim 20, further comprising an actuator controlled by the controller in order to cause the focusing optic to change a location of the target focal point.

26. The laser system of claim 20, wherein the target focal point is adjacent an eye retina to allow for laser treatment at a desired depth with minimal damage to adjacent tissues.

27. The laser system of claim 20, wherein the target focal point is adjacent the eye lens to allow for at least one of cataract and refractive correction surgery.

28. The laser system of claim 20, further comprising an objective lens having an aperture that is operable to limit a numerical aperture in order to change a length over which the laser alters tissue of the eye.

29. The laser system of claim 20, wherein the target focal point is at an intraocular lens, and the at least one pulse modifies stiffness of an arm extending from the intraocular lens to adjust its position in the eye.

30. The laser system of claim 20, wherein the target focal point in at an intraocular lens, and the at least one pulse alters a refractive characteristic of the intraocular lens through multi-photon excitation.

31. The laser system of claim 20, wherein the controller adjusts intensity of diodes pumping the laser, further comprising an attenuator controlling bandwidth and output intensity of the laser.

32. The laser system of claim 20, wherein the target focal point is within a stroma and the at least one pulse alters a refractive characteristic of an intraocular lens through multi-photon excitation.

33. The laser system of claim 20, wherein the target focal point is within a stroma of the eye and the laser changes a refractive characteristic in order to affect overall optical focusing properties of a cornea of the eye to achieve refractive correction without cutting.

34. The laser system of claim 20, wherein the target focal point is within an artificial intraocular lens and the laser changes a refractive characteristic in order to fine tune an overall optical focusing property of the intraocular lens to achieve refractive correction without surgery.

35. An ophthalmic surgical laser system comprising:

an ophthalmic laser emitting at least one laser pulse, each having a duration less than 150 fs;

a programmable controller connected to the laser; and

a detector connected to the controller, the detector operably detecting at least one of;

(a) second harmonic generation imaging; and

(b) at least two-photon fluorescence emission imaging, caused by the laser pulse being emitted into an eye;

the controller operably determining at least one of;

(i) measurements, (ii) locations, and (iii) characteristics, of portions of the eye based on the detected images, used in subsequent laser treatment of the eye.

36. The laser system of claim 35, wherein the detector detects multi-photon fluorescence emission, and the pulse duration is less than 100 fs.

37. The laser system of claim 35, wherein the detector detects second harmonic generation emission, and the pulse duration is less than 100 fs.

38. The laser system of claim 35, further comprising a pulse shaper connected to the controller, the controller automatically varying the pulse shaper in a real time manner to change a characteristic of the at least one pulse.

39. The laser system of claim 35, wherein the detector and controller detect an image of an iris of the eye and automatically compare a detected image to a previously stored iris image in order to identify the eye being treated and assist with alignment.

40. The laser system of claim 35, further comprising a pulse shaper connected to the controller, the controller automatically varying the pulse shaper in real time based on required depth to provide optimal dispersion pre-compensation.

41. An ophthalmic surgical laser system comprising:

an ophthalmic laser emitting at least one laser pulse, each having a duration less than 150 fs;

a nonlinear optical-compatible interface being substantially transparent and having a concave eye-contacting surface, an opposite surface of the interface including an anti-reflective coating adapted for the wavelength of the laser; and

marks located at the opposite surface and at least one location between the eye-contacting and opposite surfaces assisting with three dimensional alignment, the marks causing high efficiency non-linear optical emission;

the at least one laser pulse being emitted through the interface during ophthalmic surgery.

42. The laser system of claim 41, further comprising a detector receiving a signal based on the non-linear optical characteristic when the at least one laser pulse is emitted onto the marks, and a controller connected to the detector and automatically causing instrument alignment to the interface based at least in part on the signal received by the detector.

43. The laser system of claim 41, wherein the detector is a CCD camera.

44. The laser system of claim 41, wherein the detector is a photo-multiplier tube.

45. The laser system of claim 41, wherein the marks include a dye selected from the group of cyanine, fluorescein, rhodamine, and zinc oxide.

46. The laser system of claim 41, wherein the marks are placed at different depths.

47. The laser system of claim 41, wherein at least one of the marks has a linear shape and the interface is transparent with one surface matching the curvature of the eye and the opposite surface being substantially flat.

48. The laser system of claim 41, further comprising access ports laterally extending inside of the interface to allow surgical tool access to a portion of an eye covered by the interface.

49. The laser system of claim 41, wherein the marks are made by laser ablation.

50. An ophthalmic surgical laser system comprising:

a laser operably emitting a laser beam;

a programmable controller connected to the laser beam;

a display screen connected to the controller and displaying an eye; and

a pulse shaper operably shaping the laser beam between the laser and the eye;

the controller assisting in using the laser beam to cut a deteriorated lens of the eye in a contiguous pattern to allow it to be collapsed and removed from the eye as a single piece.

51. The laser system of claim 50, wherein the laser beam includes a set of pulses each having a duration of less than 100 fs.

52. The laser system of claim 50, wherein the laser beam includes a set of pulses each having a duration of less than 40 fs.

53. The laser system of claim 50, wherein the contiguous pattern is a spiral cut.

54. The laser system of claim 50, wherein the contiguous pattern is an accordion zig-zag cut.

55. An ophthalmic laser system comprising:

a first ophthalmic titanium sapphire laser;

at least a second ophthalmic titanium sapphire laser;

an ophthalmic machine unit including a patient support, the titanium sapphire lasers being interchangeably mounted to the machine unit in a modularized manner; and

a single pump laser mounted to the machine unit providing energy to whichever of the titanium sapphire lasers is being used.

56. The laser system of claim 55, wherein the single pump laser provides continuous energy of about 3-5 Watts centered at about 530 nm to each titanium sapphire oscillator.

57. The laser system of claim 55, wherein a laser pulse emitting into an eye of a patient for ophthalmic treatment has a duration less than 50 fs with an output less than 100 nJ and a repetition rate greater than 10 MHz.

58. The laser system of claim 55, wherein the titanium sapphire lasers treat macular degeneration or fundus imaging of an eye of the patient.

59. The laser system of claim 55, wherein pulses from at least one of the titanium sapphire lasers provide a high resolution image of a retina of the patient at different depths in order to provide comprehensive health diagnosis based on vasculature and/or on the relative composition of metabolic compounds.

60. The laser system of claim 55, wherein pulses from at least one of the titanium sapphire lasers provide a high resolution image of an endothelium of the patent to determine eye health of the patient.

61. The laser system of claim 55, wherein pulses from at least one of the titanium sapphire lasers activate gold nanoparticles in an eye of the patient to treat the eye.