Optical coherence tomographic system for ophthalmic surgery

• US 8,414,564 B2
• Filed: 02/18/2010
• Issued: 04/09/2013
• Est. Priority Date: 02/18/2010
• Status: Active Grant

• Current Assignee: Alcon Incorporated
• Original Assignee: Alcon LenSx, Inc. (Alcon Incorporated)
• Inventors: Goldshleger, Ilya, Holland, Guy, Raksi, Ferenc
• Primary Examiner(s): HASAN, MOHAMMED A
• Application Number:
  US12/708,450
• Publication Number:
  US 20110202044A1
• Time in Patent Office: 1,146 Days
• Field of Search: 606 3- 6, 606 10- 13, 606 16- 19
• US Class Current: 606/4
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61F 2009/00851 Optical coherence topography [OCT]
• CPC Class Codes: A61F 2009/0087 Lens
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 9/00825 for photodisruption
• CPC Class Codes: A61F 9/009 Auxiliary devices making contact with the eyeball and coupling in laser light, e.g. goniolenses apparatus for eye examination A61B3/0008
• CPC Class Codes: G01B 9/02044 Imaging in the frequency domain, e.g. by using a spectrometer
• CPC Class Codes: G01B 9/02078 Caused by ambiguity
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence

Abstract

Optical imaging techniques and systems provide high-fidelity optical imaging based on optical coherence tomographic imaging and can be used for optical imaging in ophthalmic surgery and imaging-guided surgery. One method for imaging an eye includes positioning the eye relative to a Spectral Domain Optical Coherence Tomographic (SD-OCT) imaging system, the eye having a first and a second structure, and imaging the eye with the SD-OCT imaging system by selecting one of a direct image and a mirror image of the first eye-structure and generating a first image-portion corresponding to the selected image of the first eye-structure, selecting one of a direct image and a mirror image of the second eye-structure and generating a first image-portion corresponding to the selected image of the second eye-structure, and suppressing the non-selected images of the first and second structures.

Claims

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

positioning the eye relative to a Spectral Domain Optical Coherence Tomographic (SD-OCT) imaging system,

the eye having a first and a second structure; and

imaging the eye with the SD-OCT imaging system by

selecting one of a direct image or a mirror image of the first eye-structure and generating a first image-portion, corresponding to the selected image of the first eye-structure;

selecting one of a direct image or a mirror image of the second eye-structure and generating a second image-portion, corresponding to the selected image of the second eye-structure; and

suppressing the non-selected images of the first and second structures.

2. The method of claim 1, wherein the generating the first and second image-portions comprises:

performing a transformation on one of the first or second image-portions to generate a biologically representative image of the first and second structures, when

at least one of the first or the second image-portions is a mirror image.

3. The method of claim 1, the imaging the eye step comprising:

adjusting a reference depth of the SD-OCT imaging system

to generate the direct and mirror images of the first and second eye-structures at corresponding image depths so that the direct and mirror images of the first and second eye-structures can be distinguished from each other.

4. The method of claim 3, the distinguishing the direct and mirror images of the first and second eye-structures step comprising at least one of:

recognizing a spatial separation of the images;

applying a pattern recognition approach;

distinguishing a signal characteristic of the images;

utilizing pre-existing knowledge about the eye;

or

utilizing knowledge about the eye based on a diagnostics, or

a combination of the recited steps.

5. The method of claim 3, wherein

the steps of adjusting the reference depth and distinguishing the direct and mirror images of the first and second eye-structures are performed iteratively.

6. The method of claim 3, wherein:

the first structure is an anterior capsule layer of a lens of the eye; and

the second structure is a posterior capsule layer of the lens of the eye.

7. The method of claim 6, the imaging the eye step comprising:

adjusting the reference depth of the SD-OCT imaging system so that a depth-sequence of the first image-portion, the second image-portion and a cornea image is one of;

direct image of the cornea—

direct image of the anterior capsule layer—

mirror image of the posterior capsule layer;

direct image of the cornea—

mirror image of the posterior capsule layer—

direct image of the anterior capsule layer;

or

mirror image of the posterior capsule layer—

direct image of the cornea—

direct image of the anterior capsule layer.

8. The method of claim 3, the adjusting the reference depth step comprising one of:

adjusting a position of a reference mirror of the SD-OCT imaging system;

or

tuning a delay element of the SD-OCT imaging system, or

a combination of the recited steps.

9. The method of claim 3, the imaging the eye step comprising:

a homodyne imaging.

10. The method of claim 3, wherein the imaging the eye step comprises:

adjusting an imaging range around the reference depth

to result in the first and the second structures being located within the imaging range.

11. The method of claim 10, wherein the adjusting the imaging range step comprises:

adjusting at least one of a central wavelength or a wavelength resolution of the SD-OCT imaging system.

12. The method of claim 10, wherein the adjusting step comprises;

adjusting the imaging range to be within the 0-15 mm range.

13. The method of claim 10, wherein the adjusting step comprises;

adjusting the imaging range to be in the 5-15 mm range.

14. The method of claim 10, wherein the imaging the eye step comprises:

adjusting a Rayleigh range around a focal depth

to result in the imaging range being less than 4 times the Rayleigh range.

15. The method of claim 3, the adjusting the reference depth step comprising:

adjusting the reference depth to be within the range of 2-15 mm.

16. The method of claim 1, the positioning the eye step comprising at least one of;

docking the eye to an interface of the SD-OCT imaging system;

immobilizing the eye;

or

minimizing a motion range of the eye relative to the SD-OCT imaging system, or

a combination of the recited steps.

17. The method of claim 1, wherein:

the SD-OCT imaging system is one of a

Spectrometer Based OCT (SB-OCT) and a Swept Source OCT (SS-OCT) imaging system.

18. The method of claim 1, wherein the imaging of the eye comprises at least one of:

creating a single z-scan;

creating a planar z-scan;

creating a z-scan along a scanning line;

or

creating a z-scan in a raster pattern, or

a combination of the recited steps.

19. An imaging system for imaging an eye, comprising:

a Spectral Domain Optical Coherence Tomographic (SD-OCT) imaging system that

positions the eye relative to the SD-OCT imaging system,

the eye having a first and a second structure;

generates a first image-portion, selected from a direct image and a mirror image of the first structure;

generates a second image-portion, selected from a direct image and a mirror image of the second structure; and

suppresses non-selected images of the first and second structures.

20. The imaging system of claim 19, the SD-OCT imaging system comprising;

an imaging light source that outputs an imaging light;

one or more beam splitters that

splits the imaging light into an imaging beam and a. reference beam; and

unifies a returned imaging light-portion and a returned reference light-portion into an interfering light;

a reference device, that returns the reference light-portion,

with a time difference proportional to a reference distance; and

an interference analyzer, that

receives the interfering light; and

generates an SD-OCT image of the eye.

21. The imaging system of claim 20, wherein:

the SD-OCT is one of a

Spectrometer Based OCT (SB-OCT) or a Swept Source OCT (SS-OCT).

22. The imaging system of claim 20, wherein:

the reference device is configured so that the returned reference light-portion is one of advanced or delayed relative to the returned imaging light-portion.

23. The imaging system of claim 20, wherein:

the reference distance of the reference mirror is related to a reference depth in the eye, wherein

the interference analyzer as a maximum imaging sensitivity at the reference depth.

24. The imaging system of claim 23, wherein:

the first structure is an anterior capsule layer of a lens of the eye;

the second structure is a posterior capsule layer of the lens of the eye;

the reference distance is adjustable to set the reference depth so that a depth-sequence of the first image-portion, the second image-portion and an image of a cornea is one of

mirror image of the posterior capsule layer—

direct image of the anterior capsule layer—

direct image of a cornea;

direct image of the anterior capsule layer—

mirror image of the posterior capsule layer—

direct image of the cornea;

or

direct image of the anterior capsule layer—

direct image of the cornea—

mirror image of the posterior capsule layer.

25. The imaging system of claim 23, wherein:

the first structure is an anterior capsule layer of a lens of the eye;

the second structure is a posterior capsule layer of the lens of the eye;

the reference distance is adjustable to set the reference depth so that a depth-sequence of the first image-portion, the second image-portion and an image of a cornea is one of

direct image of the posterior capsule layer—

mirror image of the anterior capsule layer—

mirror image of a cornea;

mirror image of the anterior capsule layer13 direct image of the posterior capsule layer13 mirror image of the cornea;

or

mirror image of the anterior capsule layer—

mirror image of the cornea—

direct image of the posterior capsule layer.

26. The imaging system of claim 23, wherein:

the reference distance is adjustable to control the reference depth to within the range of 2-15 mm.

27. The imaging system of claim 23, wherein:

the SD-OCT imaging system controls an imaging range around the reference depth into a range of one of

0 mm-15 mm and 5 mm-15 mm.

28. The imaging system of claim 19, wherein:

the SD-OCT imaging system suppresses the non-selected images by at least one of

preventing the display of generated non-selected images;

generating the non-selected images without displaying the non-selected images;

or

performing a computational step to prevent the generation of the non-selected images, or

a combination of the recited functions.

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

positioning the object relative to a Spectral Domain Optical Coherence Tomographic (SD-OCT) imaging system,

the object comprising a high contrast structure in a low contrast medium;

generating an image of the high contrast structure with the SD-OCT imaging system, corresponding to one of a direct image and a mirror image of the high contrast structure; and

suppressing a non-selected image of the high contrast structure.

30. The method of claim 29, the generating the image of the high contrast structure step comprising:

adjusting a reference depth of the SD-OCT imaging system

to generate the image of the high contrast structure at an image depth so that the image of the high contrast structure is distinguishable from a first image of a first structure.

31. The method of claim 30, the adjusting the reference depth step comprising:

distinguishing the image of the high contrast structure from the first image by at least one of

recognizing a spatial separation of the image of the high contrast structure from the first image;

applying a pattern recognition approach;

distinguishing a signal characteristic of the image of the high contrast structure and the first image;

utilizing pre-existing knowledge about the object;

or

utilizing a knowledge about the object based on a diagnostics.

32. The method of claim 29, the generating an image of the high contrast structure step comprising:

a homodyne imaging.

33. The method of claim 29, wherein the generating an image of the high contrast structure step comprises:

setting a reference depth of the SD-OCT imaging system; and

adjusting an imaging range around the reference depth

to result in the imaging range covering the high contrast structure.

34. The method of claim 33, wherein the adjusting the imaging range step comprises:

adjusting at least one of a central wavelength and a wavelength resolution of the SD-OCT imaging system

to result in the imaging range covering the high contrast structure.

35. The method of claim 33, wherein the adjusting the imaging range step comprises:

adjusting the imaging range to be within one of a range 0 mm-15 mm and 5 mm-15 mm.

36. The method of claim 33, wherein the adjusting the imaging range step comprises:

adjusting the reference depth to be within a range of 2 mm-15 mm.

37. The method of claim 33, wherein the adjusting the imaging range step comprises:

adjusting a focal depth of the SD-OCT imaging system; and

adjusting a Rayleigh range around the focal depth of the SD-OCT imaging system

to result in the imaging range being less than 4 times the Rayleigh range.

38. A surgical laser system, comprising:

a surgical laser delivery system; and

a Spectral Domain Optical Coherence Tomographic (SD-OCT) imaging system, coupled to the surgical laser delivery system, wherein

the SD-OCT imaging system

images an object having a high contrast structure in a low contrast medium;

generates an image of the high contrast structure corresponding to one of a direct image and a mirror image of the high contrast structure; and

suppresses a non-selected image of the high contrast structure.

39. The surgical laser system of claim 38, the SD-OCT imaging system comprising:

an imaging light source to output an imaging light;

one or more beam splitter that

splits the imaging light into an imaging beam and a reference beam; and

unifies a returned imaging beam-portion and a returned reference beam-portion into an interference beam;

a reference mirror, that returns the reference beam-portion,

positioned at a reference distance; and

an interference analyzer, that

receives the interference beam; and

generates an SD-OCT image of the eye.

40. The imaging system of claim 39, wherein:

the SID-OCT is one of a

Spectrometer Based OCT (SB-OCT) and a Swept Source OCT (SS-OCT).

41. The imaging system of claim 39, wherein:

the reference distance of the reference mirror is related to a reference depth in the eye, wherein

the interference analyzer has a maximum imaging sensitivity at the reference depth.

42. The imaging system of claim 41, wherein:

the reference distance is adjustable to control the reference depth to within the range of 2-15 mm.

43. The imaging system of claim 41, wherein:

the SD-OCT imaging system is configured to control an imaging range around the reference depth into a range of one of

0 mm-15 mm and 5 mm-15 mm.

44. The imaging system of claim 38, wherein:

the SD-OCT imaging system suppresses the non-selected image by at least one of

preventing the display of generated non-selected image;

generating the non-selected images without displaying the non-selected image;

or

performing a computational step to prevent the generation of the non-selected image.