Imaging Surgical Target Tissue by Nonlinear Scanning

• US 20110118609A1
• Filed: 11/16/2009
• Published: 05/19/2011
• Est. Priority Date: 11/16/2009
• Status: Active Grant

• Current Assignee: Alcon Incorporated
• Original Assignee: LensX Lasers, Inc. (Alcon Incorporated)
• Inventors: Holland, Guy, Goldshleger, Ilya, Raksi, Ferenc
• Granted Patent: US 9,492,322 B2
• Time in Patent Office: Days
• US Class Current: 600/476
• CPC Class Codes: A61B 3/0083 provided with means for patient positioning
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 3/107 for determining the shape or measuring the curvature of the cornea
• CPC Class Codes: A61B 5/0064 Body surface scanning
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/70 Means for positioning the patient in relation to the detecting, measuring or recording means
• CPC Class Codes: A61F 2009/00851 Optical coherence topography [OCT]
• CPC Class Codes: A61F 2009/0087 Lens
• CPC Class Codes: A61F 2009/0088 based on wavefront
• CPC Class Codes: A61F 2009/00882 based on topography
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61F 9/00825 for photodisruption
• CPC Class Codes: A61F 9/00829 Correction of higher orders
• CPC Class Codes: A61F 9/00834 Inlays; Onlays; Intraocular lenses [IOL]

Abstract

Systems and techniques for laser surgery based on imaging a target tissue by nonlinear scanning are presented. In one implementation, a method for guiding an eye surgery can include the steps of: positioning an eye in relation to an imaging system; creating first scan data by determining a depth of an eye target region at a first set of points along a first arc; creating second scan data by determining a depth of the eye target region at a second set of points along a second arc; determining target region parameters based on the first and second scan data; and adjusting one or more surgical position parameters according to the determined target region parameters.

Claims

1. A method for guiding an eye surgery, comprising the steps of:

positioning an eye in relation to an imaging system;

creating first scan data by determining a depth of an eye target region at a first set of points along a first arc;

creating second scan data by determining a depth of the eye target region at a second set of points along a second arc;

determining target region parameters based on the first and second scan data; and

adjusting one or more surgical position parameters according to the determined target region parameters.

2. The method of claim 1, wherein the determining the depth comprises:

imaging the eye target region with at least one of an optical coherence tomography (OCT) method, an ultrasound-based method, a microscopic method and an interference based method.

3. The method of claim 1, wherein:

the eye target region is one of

a corneal target region, an anterior lens surface, a posterior lens surface, a lens target region, an ophthalmic layer, and a surface defined by a pupil.

4. The method of claim 1, wherein:

at least one of the first arc and the second arc forms at least part of a closed loop.

5. The method of claim 1, wherein:

the first arc is a portion of a first intersection line where a first scanning surface intersects the eye target region; and

the second arc is a portion of a second intersection line where a second scanning surface intersects the eye target region.

6. The method of claim 1, wherein:

the first arc is a portion of a first intersection line where a first cylinder intersects the eye target region; and

the second arc is a portion of a second intersection line where a second cylinder intersects the eye target region.

7. The method of claim 6, wherein:

the first cylinder and the second cylinder are concentric, sharing a Z axis.

8. The method of claim 6, wherein:

a Z axis of the second cylinder is offset from a Z axis of the first cylinder.

9. The method of claim 1, wherein the determining target region parameters step comprises:

extracting scan characteristics from the first and second scan data.

10. The method of claim 9, wherein the extracting scan characteristics step comprises:

extracting a first amplitude and a first phase of the first scan data; and

extracting a second amplitude and a second phase of the second scan data.

11. The method of claim 10, wherein the determining of target region parameters step comprises:

determining a position parameter of a center of the target region based on the first amplitude, first phase, second amplitude and second phase.

12. The method of claim 10, wherein the determining of the target region parameters step comprises:

determining an object shape parameter of the target region based on the first amplitude, first phase, second amplitude and second phase.

13. The method of claim 10, wherein the determining of the target region parameters step comprises:

determining an object orientation parameter based on the first amplitude, first phase, second amplitude and second phase.

14. The method of claim 10, wherein the determining of the target region parameters step comprises:

determining a position parameter update, related to a position of the target region and a reference point.

15. The method of claim 1, wherein the adjusting the surgical position parameter comprises:

adjusting a position parameter of a surgical pattern center to align the surgical pattern center with a center of the target region.

16. The method of claim 1, wherein the method contains:

no more scans after the first scan and the second scan.

17. The method of claim 1, wherein:

the time from the starting of the first scanning step to the finishing of the determining the surgical position parameters step is no more than one of 100 milliseconds, 1,000 milliseconds and 10,000 milliseconds.

18. The method of claim 1, wherein:

at least one of the first and second arc is elliptical.

19. The method of claim 1, wherein:

at least one of the first arc and the second arc is an open arc; and

at least one of the first scan data and the second scan data have a maximum and a minimum.

20. The method of claim 1, wherein

the eye target region is a region of a lens of the eye;

the target region parameters comprise

a shape parameter of the lens,

a tilt parameter of the lens, and

a position parameter of the lens.

21. The method of claim 1, wherein the determining target region parameters step comprises:

fitting a function with at least one fitting parameter to the first scan data; and

determining the target region parameters using the fitting parameter.

22. A method for imaging an object, the method comprising the steps of:

positioning the object relative to an imaging system, wherein

a shape of the object is describable in terms of one or more shape parameter;

creating scan data by determining a coordinate of the object at a set of points along an arc; and

determining an object shape parameter and an object position parameter based on the scan data.

23. The method of claim 22, wherein:

the object is a portion of a spherical surface layer; and

the determined object shape parameter is a radius of the spherical surface layer.

24. The method of claim 22, wherein:

the object is an anterior lens surface layer of an eye;

the object coordinate is a Z coordinate;

the object shape parameter is a radius of the anterior lens surface layer; and

the object position parameter is a coordinate of a center of the anterior lens surface.

25. The method of claim 22, wherein the determining the object position parameter step comprises:

imaging the object with at least one of an optical coherence tomography (OCT) method, an ultrasound-based method, a microscopic method and an interference based method.

26. The method of claim 22, wherein the determining the object shape parameter and object position parameter step comprises:

creating auxiliary scan data by determining a coordinate of the object at an auxiliary set of points along an auxiliary arc.

27. The method of claim 26, wherein the determining the object shape parameter and object position parameter step comprises:

determining the object shape parameter and the object position parameter from the scan data and the auxiliary scan data.

28. The method of claim 26, wherein:

the coordinate of the object is a Z coordinate of an object layer; and

the arc is a portion of an intersection line where a scanning cylinder intersects the object layer.

29. The method of claim 28, wherein the determining the object shape parameter step comprises:

determining the Z coordinate of the object layer at the auxiliary set of points along an intersection line where an auxiliary cylinder intersects the object layer.

30. The method of claim 29, wherein:

the scanning cylinder and the auxiliary cylinder are essentially concentric, sharing a Z axis.

31. The method of claim 28, wherein the determining the object shape parameter and object position parameter step comprises:

extracting an amplitude and a phase of the scan data; and

determining a center of the object layer based on the extracted amplitude and phase.

32. The method of claim 22, wherein:

the object position parameter is one of a parameter of a center of the object layer and a perimeter of the object layer.

33. The method of claim 22, wherein the method contains:

no more scans after the scan and an auxiliary scan.

34. The method of claim 22, wherein:

the determining of the object position parameter and the object shape parameter are performed in an integrated manner.

35. The method of claim 22, wherein:

the object is one of a closed object and an open object.

36. A method for guiding eye surgery, comprising the steps of:

(a) positioning an eye relative to a surgical laser system,

the surgical laser system having a surgical position parameter and the eye having a lens;

(b) determining position data of a lens target region along a scanning arc;

(c) determining a lens position parameter based on the position data;

(d) adjusting the surgical position parameter according to the determined lens position parameter; and

(e) repeating steps (b)-(d) during the eye surgery to readjust the surgical position parameter.

37. The method of claim 36, wherein the lens target is one of:

an anterior lens surface, an anterior surface defined by a pupil, a lens target region, and a posterior lens surface.

38. The method of claim 36, wherein the determining of the lens position parameters step comprises:

extracting an amplitude and a phase of the position data.

39. The method of claim 38, wherein the determining of the lens position parameters step comprises:

determining a position parameter of a center of the lens target based on the amplitude and phase of the position data.

40. The method of claim 36, wherein the adjusting a surgical position parameter comprises:

adjusting a position parameter of a surgical pattern center to align a surgical pattern in three dimensions with respect to a characteristic feature of the lens.