Ophthalmic wavefront sensor operating in parallel sampling and lock-in detection mode

• US 8,777,413 B2
• Filed: 04/30/2012
• Issued: 07/15/2014
• Est. Priority Date: 01/20/2006
• Status: Expired due to Fees

• Current Assignee: Clarity Medical Systems, Inc.
• Original Assignee: Clarity Medical Systems, Inc.
• Inventors: Zhou, Yan, Shea, William, Baker, Phil
• Primary Examiner(s): MAI, HUY KIM
• Application Number:
  US13/459,914
• Publication Number:
  US 20120268717A1
• Time in Patent Office: 806 Days
• Field of Search: 351/205, 351/210, 351/211, 351/212, 351/214, 351/221, 351/246, 351/247
• US Class Current: 351/210
• CPC Class Codes: A61B 3/1015 for wavefront analysis
• CPC Class Codes: A61B 3/103 for determining refraction, e.g. refractometers, skiascopes
• CPC Class Codes: A61B 3/12 for looking at the eye fundus, e.g. ophthalmoscopes A61B3/13 takes precedence
• CPC Class Codes: G01J 1/0414 using plane or convex mirrors, parallel phase plates, or plane beam-splitters
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 9/00 Measuring optical phase difference devices or arrangements for controlling the phase of light beams G02F1/01; Determining degree of coherence; Measuring optical wavelength spectrometry G01J3/00

Abstract

One embodiment of the present invention is an ophthalmic wavefront sensor for use with an ophthalmic microscope to provide continuous measurements of the refractive state of an eye. The wavefront sensor operates in both parallel sampling and lock-in detection mode by synchronizing the pulsing of the light source with a multiple number of position sensing devices/detectors used for detecting the centroid position of the sampled sub-wavefronts. Other embodiments include a beam scanner to sample selected portions of the wavefront and a live image sensor and a tracking deflector.

Claims

1. An ophthalmic wavefront sensor comprising:

a light source configured to receive a reference signal oscillating/pulsing at a reference frequency and to generate a beam of light formed by pulses of light at the reference frequency;

a beam directing element configured to launch the beam of light from the light source into a patient eye and where a portion of the beam of light returned from the patient eye forms an object wavefront in the form of light pulses at the reference frequency;

an optical wavefront relay system, configured to relay an object wavefront from an object plane located at the anterior portion of a patient eye to a wavefront image plane along a beam path that can guide an incident wavefront relay beam having a large diopter range at the object plane to the wavefront image plane;

an array of high frequency response position sensing devices with each position sensing device configured to detect the amount of deflection of an image spot centroid from a reference position and to output a measurement signal indicating the amount of deflection;

an array of sub-wavefront sampling elements, disposed before the array of high frequency response position sensing devices and substantially at the wavefront image plane, with each sampling element in the array of sub-wavefront sampling elements configured to sample a sub-wavefront of the relayed wavefront and to focus a sampled sub-wavefront onto a corresponding high frequency response position sensing device in the array of high frequency response position sensing devices, where the sub-wavefront sampling elements are physically spaced from each other in such a way that each sampled sub-wavefront of a high diopter range object wavefront is focused only on the corresponding high frequency response position sensing device corresponding to the sub-wavefront sampling element; and

an electronic frequency-sensitive detection system coupled to receive the reference signal and the measurement signal, with the electronic frequency-sensitive detection system configured to indicate only the magnitude of a frequency component of the measurement signal at about the reference frequency so that all noise signals, including 1/f noise, can be substantially suppressed, where f represents DC and frequencies lower than the reference frequency.

2. The ophthalmic wavefront sensor of claim 1 with the optical wavefront relay system including first and second lenses, each lens having a diameter, a focal length and an optical axis, with the optical wavefront relay system configured to relay the object wavefront from the object plane located at the anterior portion of the patient eye to a Fourier transfer plane located between the first and second lenses and to the wavefront image plane along the beam path where the focal lengths and diameters of the first and second lenses are selected to guide the incident wavefront relay beam having a large diopter range at the object plane to the wavefront image plane.

3. The wavefront sensor of claim 2 further comprising a first beam scanner disposed at the Fourier transform plane located between the first and second lenses, and configured to shift the relayed wavefront relative to the array of sub-wavefront sampling elements.

4. The wavefront sensor of claim 3 where the first beam scanner is configured to track the eye so that only desired portion(s) of the wavefront from the eye is(are) always sampled even when the eye moves.

5. The wavefront sensor of claim 3 further comprising a second beam scanner, configured to track the eye by directing the light beam for generating the object wavefront to follow the eye.

6. The wavefront sensor of claim 5 with the second beam scanner disposed at the back focal plane of the first lens of the optical wavefront relay system.

7. The wavefront sensor of claim 1 further comprising an eye image sensor configured to provide a live eye anterior image and a second directing element configured to provide an optical path for eye imaging.

8. The wavefront sensor of claim 7 further comprising a display configured to display a live eye anterior image with an overlay of a qualitative and/or quantitative result of a wavefront measurement.

9. The ophthalmic wavefront sensor of claim 1, further

comprising:

a lens disposed between the array of sub-wavefront sampling elements and the array of position sensing devices, configured to relay and optically magnify the spacing between image spots formed by the array of sub-wavefront sampling elements at an image spot plane to the plane where the array of position sensing devices are disposed.

10. An ophthalmic wavefront sensor comprising:

a light source configured to receive a reference signal oscillating/pulsing at a reference frequency and to generate a beam of light formed by pulses of light at the reference frequency;

a beam directing element configured to launch the beam of light from the light source into a patient eye and where a portion of the beam of light returned from the patient eye forms an object wavefront in the form of light pulses at the reference frequency;

a first optical wavefront relay system, configured to relay an object wavefront from a first object plane located at the anterior portion of a patient eye to a first wavefront image plane along a first beam path that can guide an incident wavefront relay beam having a large diopter range at the object plane to the first wavefront image plane;

a second optical wavefront relay system having a second object plane located substantially at the first wavefront image plane, configured to further relay the object wavefront from the second object plane to a second wavefront image plane along a second beam path that can guide the incident wavefront relay beam having a large diopter range at the first object plane to the second wavefront image plane;

an array of high frequency response position sensing devices with each position sensing device configured to detect the amount of deflection of an image spot centroid from a reference position and to output a measurement signal indicating the amount of deflection;

an array of sub-wavefront sampling elements, disposed before the array of high frequency response position sensing devices and substantially at the second wavefront image plane, with each sampling element in the array of sub-wavefront sampling elements configured to sample a sub-wavefront of the relayed wavefront and to focus a sampled sub-wavefront onto a corresponding high frequency response position sensing device in the array of high frequency response position sensing devices, where the sub-wavefront sampling elements are physically spaced from each other in such a way that each sampled sub-wavefront of a high diopter range object wavefront is focused only on the corresponding high frequency response position sensing device corresponding to the sub-wavefront sampling element; and

an electronic frequency-sensitive detection system coupled to receive the reference signal and the measurement signal, with the electronic frequency-sensitive detection system configured to indicate only the magnitude of a frequency component of the measurement signal at about the reference frequency so that all noise signals, including 1/f noise, can be substantially suppressed, where f represents DC and frequencies lower than the reference frequency.

11. The ophthalmic wavefront sensor of claim 10 with the first optical wavefront relay system including first and second lenses, each lens having a diameter, a focal length and an optical axis, where the focal lengths and diameters of the first and second lenses are selected to guide the wavefront relay beam having a large diopter range at the first object plane to the first wavefront image plane;

and

the second optical wavefront relay system including third and fourth lenses, each lens having a diameter, a focal length and an optical axis, where the focal lengths and diameters of the third and fourth lenses are selected to further guide the incident wavefront relay beam having a large diopter range at the first object plane to the second wavefront image plane.

12. The ophthalmic wavefront sensor of claim 11 with the third lens configured to guide the object wavefront to a Fourier transfer plane located between the third and fourth lenses.

13. The wavefront sensor of claim 12 further comprising a first beam scanner, disposed at the Fourier transform plane between the third lens and the fourth lens, configured to shift the relayed wavefront relative to the array of sub-wavefront sampling elements.

14. The wavefront sensor of claim 13 where the first beam scanner is configured to track the eye so that only desired portion(s) of the wavefront from the eye is(are) always sampled even when the eye moves.

15. The wavefront sensor of claim 10, further comprising a wavefront compensator disposed at the first wavefront image plane, configured to partially or fully compensate one or more wavefront aberration component(s) so that the remaining wavefront aberration component(s) can be more precisely measured.

16. The wavefront sensor of claim 10 further comprising an eye image sensor configured to provide a live eye anterior image, and a second beam directing element configured to provide an optical path for eye imaging.

17. The wavefront sensor of claim 16 further comprising a display configured to display the live eye anterior image with an overlay of a qualitative and/or quantitative result of a wavefront measurement.

18. The wavefront sensor of claim 10 further comprising a second beam scanner, configured to track the eye by directing the light beam for generating the object wavefront to follow the eye.

19. The ophthalmic wavefront sensor of claim 10, further

comprising:

a lens disposed between the array of sub-wavefront sampling elements and the array of position sensing devices, configured to relay and optically magnify the spacing between image spots formed by the array of sub-wavefront sampling elements at an image spot plane to the plane where the array of position sensing devices are disposed.

20. An ophthalmic wavefront sensor adapted to couple to an ophthalmic microscope, comprising:

a light source configured to receive a reference signal oscillating/pulsing at a reference frequency and to generate a beam of light formed by pulses of light at the reference frequency;

a first beam directing element configured to launch the beam of light from the light source into a patient eye and where a portion of the beam of light returned from the patient eye forms an object wavefront in the form of light pulses at the reference frequency;

an imaging sensor configured to provide a live eye anterior image;

a second beam directing element configured to provide an optical path for eye imaging;

an optical wavefront relay system, configured to relay an object wavefront from an object plane located at the anterior portion of a patient eye to a wavefront image plane along a beam path that can guide an incident wavefront relay beam having a large diopter range at the object plane to the wavefront image plane;

an array of high frequency response position sensing devices with each position sensing device configured to detect the amount of deflection of an image spot centroid from a reference position and to output a measurement signal indicating the amount of deflection;

an array of sub-wavefront sampling elements, disposed before the array of high frequency response position sensing devices and substantially at the wavefront image plane, with each sampling element in the array of sub-wavefront sampling elements configured to sample a sub-wavefront of the relayed wavefront and to focus a sampled sub-wavefront onto a corresponding high frequency response position sensing device in the array of high frequency response position sensing devices, where the sub-wavefront sampling elements are physically spaced from each other in such a way that each sampled sub-wavefront of a high diopter range object wavefront is focused only on the corresponding high frequency response position sensing device corresponding to the sub-wavefront sampling element; and

an electronic frequency-sensitive detection system coupled to receive the reference signal and the measurement signal and coupled to the image sensor, with the electronic frequency-sensitive detection system configured to indicate only the magnitude of a frequency component of the measurement signal at about the reference frequency so that all noise signals, including 1/f noise, can be substantially suppressed, where f represents DC and frequencies lower than the reference frequency.

21. The ophthalmic wavefront sensor of claim 20 with the optical wavefront relay system including first and second lenses, each lens having a diameter, a focal length and an optical axis, with the optical wavefront relay system configured to relay the object wavefront from the object plane located at the anterior portion of the patient eye to a Fourier transfer plane located between the first and second lenses and to the wavefront image plane along the beam path where the focal lengths and diameters of the first and second lenses are selected to guide the incident wavefront relay beam having a large diopter range at the object plane to the wavefront image plane.

22. The ophthalmic wavefront sensor of claim 21, further comprising a second beam scanner disposed at the Fourier transform plane between the first and second lenses and configured to shift the relayed wavefront relative to the array of sub-wavefront sampling elements.

23. The ophthalmic wavefront sensor of claim 22, wherein the image sensor is further configured to provide information on the eye pupil location, and the second beam scanner is configured to track the eye by shifting the relayed wavefront relative to the array of sub-wavefront sampling elements such that the same portion(s) of the wavefront from the eye is(are) sampled even when the eye is moved.

24. The ophthalmic wavefront sensor of claim 20, further comprising a first beam scanner, configured to track the eye by directing the light beam for generating the object wavefront to follow the eye.

25. The ophthalmic wavefront sensor of claim 20, further

comprising:

a lens disposed between the array of sub-wavefront sampling elements and the array of position sensing devices, configured to relay and optically magnify the spacing between image spots formed by the array of sub-wavefront sampling elements at an image spot plane to the plane where the array of position sensing devices are disposed.

26. An ophthalmic wavefront sensor adapted to couple to an ophthalmic microscope, comprising:

a light source configured to receive a reference signal oscillating/pulsing at a reference frequency and to generate a beam of light formed by pulses of light at the reference frequency;

a first beam directing element configured to launch the beam of light from the light source into a patient eye and where a portion of the beam of light returned from the patient eye forms an object wavefront in the form of light pulses at the reference frequency;

an imaging sensor configured to provide a live eye anterior image;

a second beam directing element configured to provide an optical path for eye imaging;

a first optical wavefront relay system, configured to relay an object wavefront from a first object plane located at the anterior portion of a patient eye to a first wavefront image plane along a first beam path that can guide an incident wavefront relay beam having a large diopter range at the object plane to the first wavefront image plane;

a second optical wavefront relay system having a second object plane located substantially at the first wavefront image plane, configured to further relay the object wavefront from the second object plane to a second wavefront image plane along a second beam path that can guide the incident wavefront relay beam having a large diopter range at the first object plane to the second wavefront image plane;

an array of high frequency response position sensing devices with each position sensing device configured to detect the amount of deflection of an image spot centroid from a reference position and to output a measurement signal indicating the amount of deflection;

an array of sub-wavefront sampling elements, disposed before the array of high frequency response position sensing devices and substantially at the second wavefront image plane, with each sampling element in the array of sub-wavefront sampling elements configured to sample a sub-wavefront of the relayed wavefront and to focus a sampled sub-wavefront onto a corresponding high frequency response position sensing device in the array of high frequency response position sensing devices, where the sub-wavefront sampling elements are physically spaced from each other in such a way that each sampled sub-wavefront of a high diopter range object wavefront is focused only on the corresponding high frequency response position sensing device corresponding to the sub-wavefront sampling element; and

an electronic frequency-sensitive detection system coupled to receive the reference signal and the measurement signal, with the electronic frequency-sensitive detection system configured to indicate only the magnitude of a frequency component of the measurement signal at about the reference frequency so that all noise signals, including 1/f noise, can be substantially suppressed, where f represents DC and frequencies lower than the reference frequency.

27. The ophthalmic wavefront sensor of claim 26 with the first optical wavefront relay system including first and second lenses, each lens having a diameter, a focal length and an optical axis, where the focal lengths and diameters of the first and second lenses are selected to guide the incident wavefront relay beam having a large diopter range at the first object plane to the first wavefront image plane;

and

the second optical wavefront relay system including third and fourth lenses, each lens having a diameter, a focal length and an optical axis, where the focal lengths and diameters of the third and fourth lenses are selected to guide the incident wavefront relay beam having a large diopter range at the first object plane further to the second wavefront image plane.

28. The ophthalmic wavefront sensor of claim 27 with the third lens configured to guide the object wavefront to a Fourier transfer plane located between the third and fourth lenses.

29. The ophthalmic wavefront sensor of claim 28 further comprising a second beam scanner, disposed at the Fourier transform plane between the third and fourth lenses, configured to shift the relayed wavefront relative to the array of sub-wavefront sampling elements.

30. The ophthalmic wavefront sensor of claim 29, wherein the image sensor is further configured to provide information on the eye pupil location, and the second beam scanner is configured to track the eye by shifting the relayed wavefront relative to the array of sub-wavefront sampling elements such that the same portion(s) of the wavefront from the eye is(are) sampled even when the eye is moved.

31. The ophthalmic wavefront sensor of claim 26, further comprising a first beam scanner, configured to track the eye by directing the light beam for generating the object wavefront to follow the eye.

32. The ophthalmic wavefront sensor of claim 26, further

comprising:

a lens disposed between the array of sub-wavefront sampling elements and the array of position sensing devices, configured to relay and optically magnify the spacing between image spots formed by the array of sub-wavefront sampling elements at an image spot plane to the plane where the array of position sensing devices are disposed.

33. An ophthalmic wavefront sensor comprising:

an optical wavefront relay system, configured to relay an object wavefront from an object plane located at the anterior portion of a patient eye to a wavefront image plane along a beam path that can guide an incident wavefront relay beam having a large diopter range at the object plane to the wavefront image plane;

a beam scanner/deflector disposed along the beam path, configured to fully intercept and scan the wavefront relay beam in two dimensions;

an array of position sensing devices with each position sensing device configured to detect the amount of two dimensional deflection of an image spot centroid from a reference position and to output a measurement signal indicating the amount of two dimensional deflection; and

an array of sub-wavefront sampling elements, disposed before the array of position sensing devices and substantially at the wavefront image plane, with each sampling element in the array of sub-wavefront sampling elements configured to sample a sub-wavefront of the relayed wavefront and to focus a sampled sub-wavefront onto a corresponding position sensing device in the array of position sensing devices, where the sub-wavefront sampling elements are physically spaced from each other in such a way that each sampled sub-wavefront of a high diopter range object wavefront is focused only on the corresponding position sensing device corresponding to the sub-wavefront sampling element.

34. The ophthalmic wavefront sensor of claim 33 with the optical wavefront relay system including first and second lenses, each lens having a diameter, a focal length and an optical axis, with the optical wavefront relay system configured to relay the object wavefront from the object plane located at the anterior portion of the patient eye to a Fourier transfer plane located between the first and second lenses and to the wavefront image plane along the beam path where the focal lengths and diameters of the first and second lenses are selected to guide the incident wavefront relay beam having a large diopter range at the object plane to the wavefront image plane, and with the beam scanner/deflector disposed substantially at the Fourier transfer plane located between the first and second lenses.

35. The ophthalmic wavefront sensor of claim 33, further

comprising:

a lens disposed between the array of sub-wavefront sampling elements and the array of position sensing devices, configured to relay and optically magnify the spacing between image spots formed by the array of sub-wavefront sampling elements at an image spot plane to the plane where the array of position sensing devices are disposed.

36. An ophthalmic wavefront sensor comprising:

a first optical wavefront relay system, configured to relay an object wavefront from a first object plane located at the anterior portion of a patient eye to a first wavefront image plane along a first beam path that can guide an incident wavefront relay beam having a large diopter range at the first object plane to the first wavefront image plane;

a second optical wavefront relay system having a second object plane located substantially at the first wavefront image plane, configured to further relay the object wavefront from the second object plane to a Fourier transform plane and to a second wavefront image plane along a second beam path that can guide the incident wavefront relay beam having a large diopter range at the first object plane to the second wavefront image plane;

a beam scanner/deflector disposed substantially at the Fourier transform plane, configured to fully intercept and scan the wavefront relay beam;

an array of position sensing devices with each position sensing device configured to detect the amount of deflection of an image spot centroid from a reference position and to output a measurement signal indicating the amount of deflection; and

an array of sub-wavefront sampling elements, disposed before the array of position sensing devices and substantially at the second wavefront image plane, with each sampling element in the array of sub-wavefront sampling elements configured to sample a sub-wavefront of the relayed wavefront and to focus a sampled sub-wavefront onto a corresponding position sensing device in the array of position sensing devices, where the sub-wavefront sampling elements are physically spaced from each other in such a way that each sampled sub-wavefront of a high diopter range object wavefront is focused only on the corresponding position sensing device corresponding to the sub-wavefront sampling element.

37. The ophthalmic wavefront sensor of claim 36 with the first optical wavefront relay system including first and second lenses, each lens having a diameter, a focal length and an optical axis, where the focal lengths and diameters of the first and second lenses are selected to guide the incident wavefront relay beam having a large diopter range at the first object plane to the first wavefront image plane;

and

the second optical wavefront relay system including third and fourth lenses, each lens having a diameter, a focal length and an optical axis, where the focal lengths and diameters of the third and fourth lenses are selected to further guide the incident wavefront relay beam having a large diopter range at the first object plane to the second wavefront image plane.

38. The ophthalmic wavefront sensor of claim 36, further

comprising:

a lens disposed between the array of sub-wavefront sampling elements and the array of position sensing devices, configured to relay and optically magnify the spacing between image spots formed by the array of sub-wavefront sampling elements at an image spot plane to the plane where the array of position sensing devices are disposed.

39. An ophthalmic wavefront sensor comprising:

a light source configured to receive a reference signal oscillating/pulsing at a reference frequency and to generate a beam of light formed by pulses of light at the reference frequency;

a beam directing element configured to launch the beam of light from the light source into a patient eye and where a portion of the beam of light returned from the patient eye forms an object wavefront in the form of light pulses at the reference frequency;

an optical wavefront relay system, configured to relay an object wavefront from an object plane located at the anterior portion of a patient eye to a wavefront image plane along a beam path that can guide an incident wavefront relay beam having a large diopter range at the object plane to the wavefront image plane;

an array of high frequency response position sensing devices with each position sensing device configured to detect the amount of deflection of an image spot centroid from a reference position and to output a measurement signal indicating the amount of deflection; and

an array of sub-wavefront sampling elements, disposed before the array of high frequency response position sensing devices and substantially at the wavefront image plane, with each sampling element in the array of sub-wavefront sampling elements configured to sample a sub-wavefront of the relayed wavefront and to focus a sampled sub-wavefront onto a corresponding high frequency response position sensing device in the array of high frequency response position sensing devices, where the sub-wavefront sampling elements are physically spaced from each other in such a way that each sampled sub-wavefront of a high diopter range object wavefront is focused only on the corresponding high frequency response position sensing device corresponding to the sub-wavefront sampling element.

40. The ophthalmic wavefront sensor of claim 39 with the optical wavefront relay system including first and second lenses, each lens having a diameter, a focal length and an optical axis, where the focal lengths and diameters of the first and second lenses are selected to guide the wavefront relay beam having a large diopter range at the object plane to the wavefront image plane.

41. The ophthalmic wavefront sensor of claim 39, further comprising:

a lens disposed between the array of sub-wavefront sampling elements and the array of high frequency response position sensing devices, configured to relay and optically magnify the spacing between image spots formed by the array of sub-wavefront sampling elements at an image spot plane to the plane where the array of position sensing devices are disposed.