DEVICE AND METHOD FOR DETERMINING AT LEAST ONE OCULAR ABERRATION

Abstract

A device and a method for determining an ocular aberration of at least one eye of a user are disclosed. The device contains a wavefront sensing unit for measuring at least one optical wavefront with at least one light beam, from which an ocular aberration of the at least one eye of the user is determined. The device further contains at least one diffractive element for generating multiple diffraction orders in the light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on the wavefront sensing unit and in the eye of the user. The device and the method allow generating an ocular defocus map in a one-shot assessment in real-time, especially by employing an automated measurement of the ocular aberrations with regard to different eccentricities of the eye of the user in two meridians.

Claims

1. A device for determining an ocular aberration of at least one eye of a user, the device comprising: a wavefront sensing unit configured to measure at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and at least one diffractive element configured to generate multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on the wavefront sensing unit and in the at least one eye of the user, wherein the multiple diffraction orders include at least a zeroth diffraction order and at least two first diffraction orders in each meridian, and wherein at least nine light spots are generated across the wavefront sensing unit in the two meridians.

2. The device according to claim 1, wherein the at least one diffractive element is selected from at least one of: at least one single diffractive element, wherein the single diffractive element provides a two-dimensional grating configured to generate the multiple diffraction orders in the two meridians; or at least two individual diffractive elements, wherein each individual diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, wherein the at least two meridians are arranged orthogonally with respect to each other; or at least one single diffractive element, wherein the single diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, wherein the single diffractive element is configured to being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

3. The device according to claim 1, wherein the at least one diffractive element is selected from at least one of an optical grating, a hologram, and a digital light modulation element.

4. The device according to claim 3, wherein the at least one optical grating is selected from at least one of a transmissive optical grating and a reflective optical grating.

5. The device according to claim 1, further comprising at least one optical element configured to guide the at least one light beam to the at least one eye of the user and to a wavefront sensing unit.

6. The device according to claim 1, wherein the at least one optical element comprises at least one of: a beam splitter configured to split the at least one light beam into at least two partial light beams, wherein at least one of the partial light beams is guided to the at least one eye of the user; and an optical relay system configured to relay an entrance pupil plane onto a pupil plane of the at least one eye of the user, wherein the at least one diffractive element is placed in the entrance pupil plane.

7. The device according to claim 6, wherein the beam splitter is placed: in a manner that a same optical relay system configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit; or close to the at least one eye of the user, wherein the device further comprises a further optical relay system configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit.

8. The device according to claim 1, wherein the wavefront sensing unit is selected from at least one of a Shack Hartmann wavefront sensor, a camera configured to measure at least one point-spread function of an eccentric wavefront, a circular lenslet array aberrometer, a pyramid wavefront sensor, a phase element based wavefront sensor, and a ray tracing aberrometer.

9. The device according to claim 1, further comprising at least one additional optical path, wherein at least one of a fixation target and a pupil camera is placed in the additional optical path.

10. A method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated in the at least one eye of the user and on the wavefront sensing unit, wherein the multiple diffraction orders include at least a zeroth diffraction order and at least two first diffraction orders in each meridian, wherein at least nine light spots are generated across the wavefront sensing unit in the two meridians.

11. The method according to claim 10, wherein a single diffractive element providing a two-dimensional grating is generating the multiple diffraction orders in the two meridians; or at least two individual diffractive elements are generating the multiple diffraction orders in one meridian, wherein the at least two individual meridians are arranged orthogonally with respect to each other; or at least one single diffractive element providing a one-dimensional grating is generating the multiple diffraction orders in one meridian, and is being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

12. The method according to claim 10, wherein the ocular aberration of the at least one eye of the user is determined by measuring at least one of a defocus of the at least one eye of the user, or an equivalent sphere across a retinal field of the at least one eye of the user, and wherein an ocular defocus map representing the ocular aberration of the retinal field in the at least one eye of the user is obtained.

13. The method according to claim 12, wherein the ocular defocus map comprises values related to the at least nine light spots generated across the wavefront sensing unit in the two meridians or values interpolated between the at least nine light spots generated across the wavefront sensing unit.

14. The method according to claim 10, wherein at least one of a focus-adjustable fixation target and a pupil camera are placed in at least one additional optical path, and wherein the ocular defocus map is measured during an accommodation of the at least one eye of the user to the fixation target.

15. A computer program product being stored on a non-transitory storage medium and having instructions to cause the device according to claim 1 to execute a method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by the at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on a wavefront sensing unit and in the at least one eye of the user, wherein the multiple diffraction orders include at least a zeroth diffraction order and at least two first diffraction orders in each meridian, and wherein at least nine light spots are generated across the wavefront sensing unit in the two meridians.

16. A method for producing at least one spectacle lens for the at least one eye of the user, wherein the producing of the spectacle lens comprises processing a lens blank, wherein the processing of the lens blank is based on instructions configured to compensate at least one ocular aberration of the at least one eye of the user, and wherein the ocular aberration of the at least one eye is determined by the method for determining the ocular aberration of the at least one eye of the user according to claim 10.

17. A device for determining an ocular aberration of at least one eye of a user, the device comprising: a wavefront sensing unit configured to measure at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and at least one diffractive element configured to generate multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on the wavefront sensing unit and in the at least one eye of the user, wherein the ocular aberration of the at least one eye of the user is determined by measuring at least one of a defocus of the at least one eye of the user or an equivalent sphere across a retinal field of the at least one eye of the user, wherein an ocular defocus map representing the ocular aberration of the retinal field in the at least one eye of the user is obtained, and wherein the ocular defocus map includes at least one of: values related to at least nine light spots generated across the wavefront sensing unit in the two meridians, or values interpolated between the at least nine light spots generated across the wavefront sensing unit.

18. The device according to claim 17, wherein the at least one diffractive element is selected from at least one of: at least one single diffractive element, wherein the single diffractive element provides a two-dimensional grating configured to generate the multiple diffraction orders in the two meridians; or at least two individual diffractive elements, wherein each individual diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, wherein the at least two meridians are arranged orthogonally with respect to each other; or at least one single diffractive element, wherein the single diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, and wherein the single diffractive element is configured to being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

19. The device according to claim 17, wherein the at least one diffractive element is selected from at least one of an optical grating, a hologram, and a digital light modulation element.

20. The device according to claim 19, wherein the at least one optical grating is selected from at least one of a transmissive optical grating and a reflective optical grating.

21. The device according to claim 17, further comprising at least one optical element configured to guide the at least one light beam to the at least one eye of the user and to a wavefront sensing unit.

22. The device according to claim 17, wherein the at least one optical element comprises at least one of: a beam splitter configured to split the at least one light beam into at least two partial light beams, wherein at least one of the partial light beams is guided to the at least one eye of the user; or an optical relay system configured to relay an entrance pupil plane onto a pupil plane of the at least one eye of the user, wherein the at least one diffractive element is placed in the entrance pupil plane.

23. The device according to claim 22, wherein the beam splitter is placed: in a manner that a same optical relay system is configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit; or close to the at least one eye of the user, wherein the device further includes a further optical relay system configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit.

24. The device according to claim 17, wherein the wavefront sensing unit is selected from at least one of a Shack Hartmann wavefront sensor, a camera configured to measure at least one point-spread function of an eccentric wavefront, a circular lenslet array aberrometer, a pyramid wavefront sensor, a phase element based wavefront sensor, and a ray tracing aberrometer.

25. The device according to claim 17, further comprising at least one additional optical path, wherein at least one of a fixation target and a pupil camera is placed in the additional optical path.

26. A method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on a wavefront sensing unit and in the at least one eye of the user, wherein the ocular aberration of the at least one eye of the user is determined by measuring at least one of a defocus of the at least one eye of the user or an equivalent sphere across a retinal field of the at least one eye of the user, wherein an ocular defocus map representing the ocular aberration of the retinal field in the at least one eye of the user is obtained, and wherein the ocular defocus map includes at least one of: values related to at least nine light spots generated across the wavefront sensing unit in the two meridians, or values interpolated between the at least nine light spots generated across the wavefront sensing unit.

27. The method according to claim 26, wherein a single diffractive element providing a two-dimensional grating is generating the multiple diffraction orders in the two meridians; or at least two individual diffractive elements are generating the multiple diffraction orders in one meridian, wherein the at least two individual meridians are arranged orthogonally with respect to each other; or at least one single diffractive element providing a one-dimensional grating is generating the multiple diffraction orders in one meridian, and is being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

28. The method according to claim 26, wherein the ocular aberration of the at least one eye of the user is determined by measuring at least one of a defocus of the at least one eye of the user, or an equivalent sphere across a retinal field of the at least one eye of the user, and wherein an ocular defocus map representing the ocular aberration of the retinal field in the at least one eye of the user is obtained.

29. The method according to claim 26, wherein the multiple diffraction orders comprise at least a zeroth diffraction order and at least two first diffraction orders in each meridian, and wherein at least nine light spots are generated across the wavefront sensing unit in the two meridians.

30. The method according to claim 26, wherein at least one of a focus-adjustable fixation target and a pupil camera is placed in at least one additional optical path, and wherein the ocular defocus map is measured during an accommodation of the at least one eye of the user to the fixation target.

31. A computer program product being stored on a non-transitory storage medium and having instructions to cause the device according to claim 17 to execute a method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by the at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on a wavefront sensing unit and in the at least one eye of the user, wherein the ocular aberration of the at least one eye of the user is determined by measuring at least one of a defocus of the at least one eye of the user or an equivalent sphere across a retinal field of the at least one eye of the user, wherein an ocular defocus map representing the ocular aberration of the retinal field in the at least one eye of the user is obtained, and wherein the ocular defocus map includes at least one of: values related to at least nine light spots generated across the wavefront sensing unit in the two meridians, or values interpolated between the at least nine light spots generated across the wavefront sensing unit.

32. A method for producing at least one spectacle lens for at least one eye of a user, wherein the producing of the spectacle lens comprises processing a lens blank, wherein the processing of the lens blank is based on instructions configured to compensate at least one ocular aberration of the at least one eye of the user, and wherein the ocular aberration of the at least one eye is determined by the method for determining the ocular aberration of the at least one eye of the user according to claim 26.

33. A device for determining an ocular aberration of at least one eye of a user, the device comprising: a wavefront sensing unit configured to measure at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; at least one diffractive element configured to generate multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on the wavefront sensing unit and in the at least one eye of the user; and at least one optical element configured to guide the at least one light beam to the at least one eye of the user and to a wavefront sensing unit, wherein the at least one optical element includes: a beam splitter configured to split the at least one light beam into at least two partial light beams, wherein at least one of the partial light beams is guided to the at least one eye of the user; and oan optical relay system configured to relay an entrance pupil plane onto a pupil plane of the at least one eye of the user, wherein the at least one diffractive element is placed in the entrance pupil plane; and wherein the beam splitter is placed in a manner that a same optical relay system is configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit.

34. The device according to claim 33, wherein the at least one diffractive element is selected from at least one of: at least one single diffractive element, wherein the single diffractive element provides a two-dimensional grating configured to generate the multiple diffraction orders in the two meridians; or at least two individual diffractive elements, wherein each individual diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, wherein the at least two meridians are arranged orthogonally with respect to each other; or at least one single diffractive element, wherein the single diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, and wherein the single diffractive element is configured to being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

35. The device according to claim 33, wherein the at least one diffractive element is selected from at least one of an optical grating, a hologram, and a digital light modulation element.

36. The device according to claim 35, wherein the at least one optical grating is selected from at least one of a transmissive optical grating and a reflective optical grating.

37. The device according to claim 33, wherein the wavefront sensing unit is selected from at least one of a Shack Hartmann wavefront sensor, a camera configured to measure at least one point-spread function of an eccentric wavefront, a circular lenslet array aberrometer, a pyramid wavefront sensor, a phase element based wavefront sensor, and a ray tracing aberrometer.

38. The device according to claim 33, further comprising at least one additional optical path, wherein at least one of a fixation target and a pupil camera is placed in the additional optical path.

39. A method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on a wavefront sensing unit and in the at least one eye of the user; and c) guiding the at least one light beam by at least one optical element to the at least one eye of the user and to a wavefront sensing unit, wherein the at least one optical element includes: a beam splitter configured to split the at least one light beam into at least two partial light beams, wherein at least one of the partial light beams is guided to the at least one eye of the user; and an optical relay system configured to relay an entrance pupil plane onto a pupil plane of the at least one eye of the user, wherein the at least one diffractive element is placed in the entrance pupil plane, and wherein the beam splitter is placed in a manner that the same optical relay system is configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit.

40. The method according to claim 39, wherein a single diffractive element providing a two-dimensional grating is generating the multiple diffraction orders in the two meridians; or at least two individual diffractive elements are generating the multiple diffraction orders in one meridian, wherein the at least two individual meridians are arranged orthogonally with respect to each other; or at least one single diffractive element providing a one-dimensional grating is generating the multiple diffraction orders in one meridian, and is being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

41. The method according to claim 39, wherein the ocular aberration of the at least one eye of the user is determined by measuring at least one of a defocus of the at least one eye of the user, or an equivalent sphere across a retinal field of the at least one eye of the user, and wherein an ocular defocus map representing the ocular aberration of the retinal field in the at least one eye of the user is obtained.

42. The method according to claim 39, wherein the multiple diffraction orders comprise at least a zeroth diffraction order and at least two first diffraction orders in each meridian, and wherein at least nine light spots are generated across the wavefront sensing unit in the two meridians.

43. The method according to claim 42, wherein the ocular defocus map comprises values related to the at least nine light spots generated across the wavefront sensing unit in the two meridians or values interpolated between the at least nine light spots generated across the wavefront sensing unit.

44. The method according to claim 39, wherein at least one of a focus-adjustable fixation target and a pupil camera is placed in at least one additional optical path, and wherein the ocular defocus map is measured during an accommodation of the at least one eye of the user to the fixation target.

45. A computer program product stored on a non-transitory storage medium and having instructions to cause the device according to claim 33 to execute a method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by the at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on a wavefront sensing unit and in the at least one eye of the user; and c) guiding the at least one light beam by at least one optical element to the at least one eye of the user and to a wavefront sensing unit, wherein the at least one optical element includes: a beam splitter configured to split the at least one light beam into at least two partial light beams, wherein at least one of the partial light beams is guided to the at least one eye of the user; and an optical relay system configured to relay an entrance pupil plane onto a pupil plane of the at least one eye of the user, wherein the at least one diffractive element is placed in the entrance pupil plane, wherein the beam splitter is placed in a manner that a same optical relay system is configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit.

46. A method for producing at least one spectacle lens for at least one eye of a user, wherein the producing of the spectacle lens comprises processing a lens blank, wherein the processing of the lens blank is based on instructions configured to compensate at least one ocular aberration of the at least one eye of the user, and wherein the ocular aberration of the at least one eye is determined by the method for determining the ocular aberration of the at least one eye of the user according to claim 39.

47. A device for determining an ocular aberration of at least one eye of a user, the device comprising: a wavefront sensing unit configured to measure at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and at least one diffractive element configured to generate multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on the wavefront sensing unit and in the at least one eye of the user, wherein the device further comprises at least one additional optical path, and wherein at least one of a fixation target and a pupil camera are placed in the additional optical path.

48. The device according to claim 47, wherein the at least one diffractive element is selected from at least one of: at least one single diffractive element, wherein the single diffractive element provides a two-dimensional grating configured to generate the multiple diffraction orders in the two meridians; or at least two individual diffractive elements, wherein each individual diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, wherein the at least two meridians are arranged orthogonally with respect to each other; or at least one single diffractive element, wherein the single diffractive element provides a one-dimensional grating configured to generate the multiple diffraction orders in one meridian, and wherein the single diffractive element is configured to being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

49. The device according to claim 47, wherein the at least one diffractive element is selected from at least one of an optical grating, a hologram, and a digital light modulation element.

50. The device according to claim 49, wherein the at least one optical grating is selected from at least one of a transmissive optical grating and a reflective optical grating.

51. The device according to claim 47, further comprising at least one optical element configured to guide the at least one light beam to the at least one eye of the user and to the wavefront sensing unit.

52. The device according to claim 47, wherein the at least one optical element comprises at least one of: a beam splitter configured to split the at least one light beam into at least two partial light beams, wherein at least one of the partial light beams is guided to the at least one eye of the user; and an optical relay system configured to relay an entrance pupil plane onto a pupil plane of the at least one eye of the user, wherein the at least one diffractive element is placed in the entrance pupil plane.

53. The device according to claim 52, wherein the beam splitter is placed: in a manner that a same optical relay system is configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit; or close to the at least one eye of the user, wherein the device further comprises a further optical relay system configured to relay the entrance pupil plane to a surface plane of the wavefront sensing unit.

54. The device according to claim 47, wherein the wavefront sensing unit is selected from at least one of a Shack Hartmann wavefront sensor, a camera configured to measure at least one point-spread function of an eccentric wavefront, a circular lenslet array aberrometer, a pyramid wavefront sensor, a phase element based wavefront sensor, and a ray tracing aberrometer.

55. A method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on a wavefront sensing unit and in the at least one eye of the user, wherein the method further comprises providing an additional optical path, and wherein at least one of a fixation target and a pupil camera is placed in the additional optical path.

56. The method according to claim 55, wherein a single diffractive element providing a two-dimensional grating is generating the multiple diffraction orders in the two meridians; or at least two individual diffractive elements are generating the multiple diffraction orders in one meridian, wherein the at least two individual meridians are arranged orthogonally with respect to each other; or at least one single diffractive element providing a one-dimensional grating is generating the multiple diffraction orders in one meridian, and is being rotated in a manner that the multiple diffraction orders are provided in the two meridians.

57. The method according to claim 55, wherein the ocular aberration of the at least one eye of the user is determined by measuring at least one of a defocus of the at least one eye of the user, or an equivalent sphere across a retinal field of the at least one eye of the user, and wherein an ocular defocus map representing the ocular aberration of the retinal field in the at least one eye of the user is obtained.

58. The method according to claim 55, wherein the multiple diffraction orders comprise at least a zeroth diffraction order and at least two first diffraction orders in each meridian, and wherein at least nine light spots are generated across the wavefront sensing unit in the two meridians.

59. The method according to claim 58, wherein the ocular defocus map comprises values related to the at least nine light spots generated across the wavefront sensing unit in the two meridians or values interpolated between the at least nine light spots generated across the wavefront sensing unit.

60. The method according to claim 55, wherein at least one of a focus-adjustable fixation target and a pupil camera are placed in at least one additional optical path, and wherein the ocular defocus map is measured during an accommodation of the at least one eye of the user to the fixation target.

61. A computer program product stored on a non-transitory storage medium and having instructions to cause the device according to claim 47 to execute a method for determining an ocular aberration of at least one eye of a user, the method comprising the following steps: a) measuring at least one optical wavefront comprised by the at least one light beam, wherein an ocular aberration of the at least one eye of the user is determined from the at least one optical wavefront; and b) generating multiple diffraction orders in the at least one light beam in two meridians in a manner that the multiple diffraction orders are spatially separated on a wavefront sensing unit and in the at least one eye of the user, wherein the device further comprises an additional optical path, and wherein at least one of a fixation target and a pupil camera are placed in the additional optical path.

62. A method for producing at least one spectacle lens for the at least one eye of a user, wherein the producing of the spectacle lens comprises processing a lens blank, wherein the processing of the lens blank is based on instructions configured to compensate at least one ocular aberration of the at least one eye of the user, and wherein the ocular aberration of the at least one eye is determined by the method for determining the ocular aberration of the at least one eye of the user according to claim 55.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0119] The disclosure will now be described with reference to the drawings wherein:

[0120] FIG. 1 illustrates a preferred embodiment of a device for determining at least one ocular aberration of at least one eye of a user according to the present disclosure;

[0121] FIG. 2 illustrates a further preferred embodiment of the device for determining the at least one ocular aberration of the at least one eye of the user according to the present disclosure;

[0122] FIG. 3 illustrates a further preferred embodiment of the device for determining the at least one ocular aberration of the at least one eye of the user according to the present disclosure;

[0123] FIG. 4 illustrates a further preferred embodiment of the device for determining the at least one ocular aberration of the at least one eye of the user according to the present disclosure;

[0124] FIG. 5 illustrates a diagram indicating an energy spread across different diffraction orders;

[0125] FIG. 6 illustrates a diagram indicating a spatial separation of multiple diffraction orders on the Shack Hartmann wavefront sensor; and

[0126] FIG. 7 illustrates a preferred embodiment of a method for determining at least one ocular aberration of at least one eye of a user according to the present disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0127] FIG. 1 illustrates a preferred embodiment of a device 110 for determining at least one ocular aberration of at least one eye 112 of a user, wherein the eye 112 comprises a retina 114. In the following, the FIGS. and the description refer, for sake of simplicity, however, only to one eye 112 of the user. As schematically depicted there, the device 110 may comprise a light source 116, preferably a monochromatic source, most preferred a laser diode, particularly by virtue of its simplicity, easy availability and considerably low expenses. However, as already indicated above, a different type of light source may also be feasible. Herein, the light comprises electromagnetic radiation preferably in at least one of the visible spectral range or the near infrared spectral range, thus, having a wavelength of 380 nm to 1.5 μm. Accordingly, the light source 116 is designated for generating a light beam 118, which is guided along an optical path 120. Herein, the light beam 118 describes a propagation of the light in form of rays, wherein a direction of propagation of the rays is, generally, denoted as the optical path 120. Further, a surface being perpendicular to the direction of propagation of the rays is denoted as optical wavefront (not depicted here).

[0128] As further illustrated in FIG. 1, the device 110 may further comprise a beam splitter 122, which can be selected from any known beam splitter, in particular from a glass plate with dielectric coating, a dichroic mirror, a pellicle beam splitter, a beam splitter plate, or a polarizing beam splitter, such as a Wollaston prism, or a polarization grating. However, a different type of beam splitter may also be feasible. As schematically depicted in FIG. 1, the beam splitter 122 can, preferably, be placed in the optical path 120 in a fashion that it may split the light beam 118 as provided by the light source 116 into two partial light beams 124, 126. As a result thereof, a first partial light beam 124 is guided to the eye 112 of the user and, after being reflected by the eye 112 of the user received from the eye 112 of the user, especially for being guided via a second partial light beam 126 towards a wavefront sensing unit 128. However, as explained above in more detail, the device 110 may comprise further embodiments which are devoid of the beam splitter 122.

[0129] As further illustrated in FIG. 1, the device 110 further comprises the wavefront sensing unit 128, in particular a Shack Hartmann wavefront sensor 130. However, a further kind of wavefront sensing unit, in particular a camera designated for measuring at least one point-spread function of an eccentric wavefront, a circular lenslet array aberrometer, a pyramid wavefront sensor, a phase element based wavefront sensor, or a ray tracing aberrometer, may also be feasible. Herein, the wavefront sensing unit 128, in particular the Shack Hartmann wavefront sensor 130, is designated for measuring aberrations of the optical wavefront without requiring interference with a reference beam having no aberrations. In particular, the Shack Hartmann wavefront sensor 130 has an array of individual lenslets (not depicted here) a two-dimensional optical detector, such as a CCD array, a CMOS array, or a quad-cell as depicted in FIG. 6. Accordingly, the ocular aberration of the eye 112 of the user is determined from the optical wavefront measured by the wavefront sensing unit 128, in particular the Shack Hartmann wavefront sensor 130.

[0130] As further illustrated in FIG. 1, the device 110 further comprises a diffractive element. In the exemplary embodiments used herein, the diffractive element is an optical grating 132; however, using, alternatively or in addition, a hologram, such as a volume hologram, and/or a digital light modulation element, such as a spatial light modulator (SLM) or a digital micro-mirror unit (DMD) may also be feasible for the purposes of the present disclosure.

[0131] In the exemplary embodiments of FIGS. 1, 2, and 4, the optical grating is a transmissive optical grating 134, thus allowing the light beam 118 to traverse the optical grating 132. However, as schematically depicted in FIG. 3, a reflective optical grating 136 may also be feasible. As described above, the optical grating 132 can, further, be selected from a diffraction grating or a polarization grating. As a result of traversing the transmissive optical grating 134 or, alternatively, being reflected by the reflective optical grating 136, multiple diffraction orders as schematically depicted in FIGS. 5 and 6 are generated in the light beam 118. Herein, the optical grating 132 is placed in the at least one optical path 118 in a fashion that the desired multiple diffraction orders in the light beam 118 are generated in two meridians in a manner that the multiple diffraction orders are spatially separated as individual light spots in the eye 112, especially on the retina 114, of the user and on the optical wavefront sensing unit as further illustrated in FIGS. 5 and 6.

[0132] As further illustrated in FIG. 1, the optical grating 132 which is designated for generating the desired multiple diffraction orders in the at least one light beam 118 in the two meridians comprises two individual optical gratings 138, 138′ each having a one-dimensional grating designated for generating the multiple diffraction orders in one meridian, wherein the two individual optical gratings 138, 138′ are arranged orthogonally with respect to each other in order to generate the desired multiple diffraction orders in the at least one light beam 118 in the two meridians. With respect to the term “orthogonal,” reference can be made to the definition thereof above. As an alternative, a single optical grating (not depicted here) could also be used, wherein the single optical grating having a one-dimensional grating designated for generating the multiple diffraction orders in one meridian can be rotated in a fashion that the multiple diffraction orders are provided in the two meridians. As a further alternative, the single optical grating can be two-dimensional which is designated for generating the multiple diffraction orders in the two meridians. As schematically depicted in FIG. 1, the optical grating 132 may, preferably, be placed in an entrance pupil plane 140.

[0133] As further illustrated in FIG. 1, the device 110 may further comprise at least one optical element which is designated for guiding the at least one light beam 118 to the at least one eye 112 of the user and to a wavefront sensing unit 128. For this purpose, the at least one optical element may, preferably, comprise an optical relay system 142 which is, especially, be designated for relaying the entrance pupil plane 140 onto a pupil 144 of the eye 112 of the user, and, in addition, the beam splitter 122 which is, as described above in more detail, designated for guiding the light beam 118, in particular the partial light beam 126, on the wavefront sensing unit 128.

[0134] As schematically depicted in FIG. 1, the optical relay system 142 may, preferably, comprise a telescope 146 having two wide-angle telecentric lenses 148, 148′, which are shown in FIG. 1 as single lenses for simplification purposes and which are designated for transferring information displayed in the entrance pupil plane 140 to be displayed onto the pupil 144 of the eye 142 of the user. For a further kind of optical relay system reference may be made to FIG. 2 as well as to the description above.

[0135] As further illustrated in FIG. 1, the beam splitter 122 can be placed in a manner that the same optical relay system 142 which is used for relaying the entrance pupil plane 140 onto the pupil 144 of the eye 112 of the user is also designated for relaying the entrance pupil plane 140 to a surface 150 of the wavefront sensing unit 128, whereby a particularly simple and less expensive device 110 can be obtained. An alternative embodiment thereof is schematically depicted in FIG. 3.

[0136] FIG. 2 illustrates a further preferred embodiment of the device 110 for determining the at least one ocular aberration of the eye 112 of the user. The particular embodiment of the device 110 as schematically depicted there, differs from the particular embodiment of the device 110 as displayed in FIG. 1, that, in addition to the telescope 146 which constitutes the optical relay system 142 comprises a further telescope 152, which in addition to a further wide-angle telecentric lens 154, has a spherical mirror 156, a further beam splitter 158, and an axicon element 160 which is placed in an intermediate image plane of the further telescope 152. As described above, the axicon element 160 has a conical surface, hereby transforming the light beam 118 into a ring shaped distribution. As a result thereof, the axicon element 160 laterally shifts the pupils corresponding to the peripheral beams. As schematically depicted in FIGS. 5 and 6, the axicon element 160 generated distinct areas on the surface 150 of the wavefront sensing unit 128, wherein each distinct area comprises one individual light spot which can, thus, be separately processed without having multiple light spots under each lenslet.

[0137] For further details concerning FIG. 2, reference can be made to the exemplary embodiment of the device 110 as described above with respect to FIG. 1.

[0138] FIG. 3 illustrates a further preferred embodiment of the device 110 for determining the at least one ocular aberration of the eye 112 of the user. The particular embodiment of the device 110 as schematically depicted there, differs from the particular embodiment of the device 110 as displayed in FIG. 1, in that each of the two individual optical gratings 138, 138′ which has a one-dimensional grating designated for generating the multiple diffraction orders in one meridian is each a reflective optical grating 136 which is placed in an individual additional optical path 162, 162′, thus, requiring two additional beam splitters 164, 164′. Herein, the first individual optical grating 138 may, preferably, be placed in the entrance pupil plane 140 as described above with respect to FIG. 1. Multiple diffraction orders in one meridian are then reflected from the first individual optical grating 138. A further telescope 166 comprising further wide-angle telecentric lenses 168, 168′ relays here the entrance pupil plane 140 onto the second individual optical grating 138′ being oriented orthogonally with respect to the first individual optical grating 138. In reflection, each light beam 118 as provided by the first individual optical grating 138 is separated again, resulting in multiple diffraction orders in the two meridians.

[0139] As further illustrated in FIG. 3, the beam splitter 122 can also be placed close to the eye 112 of the user. In this arrangement, however, the device 110 further comprises a further telescope 170 having further wide-angle telecentric lenses 172, 172′, wherein the further telescope 170 is designated for relaying the entrance pupil plane 140 to the surface 150 of the wavefront sensing unit 128. Herein, the further telescope 170 comprising the further wide-angle telecentric wide-angle telecentric lenses 172, 172′ then relays the entrance pupil plane 140 to the pupil 144 of the eye 112 of the user, where all incident light multiple diffraction orders of the light beam 118 converge in a singular spot. As a result, point sources across the retina 114 of the eye 112 of the user are generated. The telescope 146 comprising the wide-angle telecentric lenses 148, 148′ conjugates the entrance pupil plane 140 to the surface 150 of the wavefront sensing unit 128, wherein the optical wavefronts resulting from each eccentricity are sampled.

[0140] For further details concerning FIG. 3, reference can be made to the exemplary embodiment of the device 110 as described above with respect to FIG. 1.

[0141] FIG. 4 illustrates a further preferred embodiment of the device 110 for determining the at least one ocular aberration of the eye 112 of the user. In this particular embodiment, the ocular defocus map can be determined from the optical wavefront even during an accommodation of the eye 112 of the user. As schematically depicted in FIG. 4, the device 110 further comprises, for this purpose, additional beam splitters 174, 174′ which open additional optical paths 176, 176′. As an alternative, the device 110 may further comprise dichroic mirrors (not depicted here), wherein the dichroic mirrors are long-pass mirrors, thus, being designated for reflecting shorter wavelengths. In particular, one of the dichroic mirrors is designated to reflect a shortest portion of the wavelengths while a further of the dichroic mirrors is designated to reflect a middle portion of the wavelengths. As a result, the longest portion of the wavelengths can pass to the wavefront sensing unit 128.

[0142] In the exemplary embodiment of FIG. 4, the first additional optical path 176 comprises a tunable lens 178 for adjusting the focus of a fixation target 180, wherein the tunable lens 178 can be replaced by a phase modulator or a Badal lens. Further, the second additional optical path 176′ comprises a pupil camera 182 which is designated for, simultaneously, measuring a movement of the pupil 144 of the eye 112 of the user and controlling a position of the pupil 144 of the eye 112 of the user to the fixation target 180 during accommodation. As a result thereof, the at least one ocular aberration of the eye 112 of the user can be determined in this fashion as a function of the accommodation of the at least one eye 112 of the user.

[0143] For further details concerning FIG. 4, reference can be made to the exemplary embodiment of the device 110 as described above with respect to FIG. 1.

[0144] FIG. 5 illustrates a diagram indicating an energy spread across the multiple diffraction orders 184, wherein a phase modulation depth of the sinusoidal diffraction grating 132 assumes a values of 0.4 π. As described above, the diffraction order 184 can be selected from a single zeroth diffraction order, one of two first diffraction orders, one of two second diffraction orders, or one of higher diffraction orders, wherein a measurable intensity of the diffraction order 184 depends on an individual diffraction efficiency 186 of each diffraction order 184. The diagram as schematically depicted in FIG. 5, allows performing a single foveal measurement 188 and at eight peripheral measurements 190 when taking into account the first diffraction orders, or twenty-five peripheral measurements 190 when, additionally, taking into account the second diffraction orders. Herein, an increase of the value of the phase modulation depth, typically, results in energy balance shifting to higher diffraction orders. If the optical grating 132 is a sinusoidal optical grating, the diffraction efficiency 186 of the multiple diffraction orders 184 can be described by using Bessel functions related to the corresponding multiple diffraction orders 184.

[0145] FIG. 6 illustrates a diagram indicating a spatial separation of the multiple diffraction orders 184 on the Shack Hartmann wavefront sensor 130. When the multiple diffraction orders 184 within the light beam 118 are combined at the entrance pupil plane 140, each lenslet of the Shack Hartmann wavefront sensor 130 can produce multiple light spots 192 as schematically depicted in FIG. 6. Herein, pitch and focal length of the lenslets are, preferably, selected in order to minimize, preferably to completely avoid, cross talk between the multiple light spots 192 on the surface 150 of the Shack Hartmann wavefront sensor 130. In FIG. 6, light spots 194, 194′, 194″ which correspond to the same diffraction order 184, are separated from the other diffraction orders 184 and processed individually. Further, a grid 196 as depicted there separates areas of the Shack Hartmann wavefront sensor 130 under each lenslet.

[0146] Based on Equation 1 above, a preferred example of parameters for the Shack Hartmann wavefront sensor 130 can be estimated. Using an optical relay having a magnification of 2.5 from the surface 150 of the Shack Hartmann wavefront sensor 130 to entrance pupil plane 140, two meridians covering a field of ±20° at the entrance pupil plane 140 and ±8° at the surface 150 of the Shack Hartmann wavefront sensor 130 are obtained. Taking into account [0147] a lenslet pitch of 1 mm; [0148] a lenslet focal length of 3 mm; and [0149] a wavelength of the light of 850 nm which is used for an Airy disk calculation), the Shack Hartmann wavefront sensor 130 could be able to measure a maximum angle of 9.53°. The eccentric beams correspond to a tilt of 8°. The dynamic range of the Shack Hartmann wavefront sensor 130 could, thus correspond, to a maximum wavefront tilt of 1.53°. By selecting these parameters no cross talk between the sensor areas under the lenslets may occur.

[0150] In addition, the dynamic range of the Shack Hartmann wavefront sensor 130 sensor can be improved by using advanced processing methods, as e.g., described by Lundström, L., & Unsbo, P. (2004), Unwrapping Hartmann-Shack images from highly aberrated eyes using an iterative B-spline based extrapolation method, Optometry and Vision Science, 81(5), 383-388.

[0151] FIG. 7 schematically illustrates a preferred embodiment of a method 210 for determining the at least one ocular aberration of the at least one eye 112 of the user according to the present disclosure.

[0152] In an illuminating step 212, the light beam 118 along the optical path 120 can be provided, preferably by using the light source 116, in particular the laser diode.

[0153] In a diffracting step 214 according to step b), the multiple diffraction orders 168 are generated in the light beam 118 in two meridians in a manner that the multiple diffraction 168 orders are spatially separated in the eye 112, especially on the retina 114, of the user and on the wavefront sensing unit 128.

[0154] In a guiding step 216, the light beam 118 which comprises the multiple diffraction orders 168 can be guided to the at least one eye 112 of the user and to the wavefront sensing unit 128. For this purpose, the light beam 118 may be split into the two partial light beams 124, 126, wherein the first partial light beam 124 may be guided to the eye 112, especially to the retina 114, of the user and received from the eye 112 of the user, especially for being guided via the second partial light beam 126 towards the wavefront sensing unit 128, especially to the surface 150 of the Shack Hartmann wavefront sensor 130.

[0155] In a measuring step 218 according to step a), the optical wavefront comprised by the light beam 118, especially by the second partial light beam 126, is measured, preferably in real-time, whereby an ocular defocus map 220 representing the ocular aberration of the retinal field in the eye 112 of the user is determined from the optical wavefront, preferably in a one-shot measurement of the eye 112 of the user. Herein, the ocular defocus map 220 may, preferably, comprise the values related to the multiple light spots 176 as generated across the wavefront sensing unit 128 in the two meridians or, more preferred, values interpolated between the multiple light spots 176. In addition, at least one algorithm, preferably selected from machine learning, or artificial intelligence, can be used for further improving the measurements.

[0156] All publications, patents and patent applications cited in this specification are herein incorporated by reference, and for any and all purposes, as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference. In the case of inconsistencies, the present disclosure will prevail.

LIST OF REFERENCE SIGNS

[0157] 110 device for determining at least one ocular aberration of at least one eye of a user [0158] 112 eye [0159] 114 retina [0160] 116 light source [0161] 118 light beam [0162] 120 optical path [0163] 122 beam splitter [0164] 124 first partial light beam [0165] 126 second partial light beam [0166] 128 wavefront sensing unit [0167] 130 Shack Hartmann wavefront sensor [0168] 132 optical grating [0169] 134 transmissive optical grating [0170] 136 reflective optical grating [0171] 138, 138′ individual optical grating [0172] 140 entrance pupil plane [0173] 142 optical relay system [0174] 144 pupil [0175] 146 telescope [0176] 148, 148′ wide-angle telecentric lens [0177] 150 surface [0178] 152 further telescope [0179] 154 further wide-angle telecentric lens [0180] 156 spherical mirror [0181] 158 further beam splitter [0182] 160 axicon element [0183] 162, 162′ additional optical path [0184] 164, 164′ additional beam splitter [0185] 166 further telescope [0186] 168, 168′ further wide-angle telecentric lens [0187] 170 further telescope [0188] 170, 172′ further wide-angle telecentric lens [0189] 174, 174′ additional beam splitter [0190] 176, 176′ additional optical path [0191] 178 tunable lens [0192] 180 focus-adjustable fixation target [0193] 182 pupil camera [0194] 184 diffraction order [0195] 186 diffraction efficiency [0196] 188 foveal measurement [0197] 190 peripheral measurement [0198] 192 light spot [0199] 194, 194′ light spot [0200] 196 grid [0201] 210 method [0202] 212 illuminating step [0203] 214 diffracting step [0204] 216 guiding step [0205] 218 measuring step [0206] 220 ocular defocus map