METHOD FOR DETERMINING A CURRENT POSITION OF A PATIENT INTERFACE OF AN EYE SURGICAL LASER BASED ON A PURKINJE IMAGE

Abstract

A method is disclosed for determining a current position of a patient interface of an eye surgical laser for an eye relative to an optical axis of a laser beam of a treatment apparatus. The method includes determining a target position of the patient interface relative to the optical axis, positioning the patient interface in a preset area in front of the optical axis, illuminating the patient interface by means of an illumination device, capturing a Purkinje image by means of the optical capturing device, comparing the captured Purkinje image to the optical axis and determining the current position of the patient interface depending thereon, comparing the current position to the target position and with a deviation, and outputting a control signal to a control device of the treatment apparatus. A treatment apparatus, a computer program and a computer-readable medium are disclosed for carrying out the method.

Claims

1.-14. (canceled)

15. A method for determining a current position of a patient interface of an eye surgical laser of a treatment apparatus for an eye of a patient relative to an optical axis of a laser beam of the laser in a neutral pose of a beam deflection device of the treatment apparatus, comprising the steps of: determining a target position of the patient interface relative to the optical axis; positioning the patient interface in a preset area in front of the optical axis; illuminating the patient interface by means of an illumination device of the treatment apparatus; capturing a Purkinje image, which is associated with the patient interface, by means of an optical capturing device of the treatment apparatus; comparing the captured Purkinje image to the optical axis and determining the current position of the patient interface depending thereon; and comparing the current position to the target position and with a deviation of the current position from the target position, outputting a control signal to a control device of the treatment apparatus.

16. The method according to claim 15, wherein a first order or second order Purkinje reflex is captured as the Purkinje image.

17. The method according to claim 15, wherein with an ascertained deviation, a control signal is generated such that a position correction of the patient interface or of the optical axis is performed.

18. The method according to claim 15, wherein after an ascertained deviation below a preset deviation threshold value, a control signal is generated such that a docking procedure of the patient interface to the eye is performed.

19. The method according to claim 15, wherein said patient interface is illuminated by means of an illumination ring or illumination point or by means of an illumination half ring or by means of illumination sectors of the illumination device for generating the Purkinje image.

20. The method according to claim 15, wherein said patient interface is illuminated with infrared light by means of an infrared illumination device and the optical capturing device is configured such that infrared light reflected on the patient interface at least in certain areas is captured.

21. The method according to claim 15, wherein the patient interface is configured electrically insulated and/or sterile.

22. The method according to claim 15, wherein with a deviation above a preset deviation threshold value, the patient interface is newly positioned as the control signal.

23. The method according to claim 15, wherein with a deviation above a preset deviation threshold value, a position variation of the eye surgical laser, in particular of the laser beam, is performed.

24. The method according to claim 15, wherein the Purkinje image is captured by means of an optical capturing device arranged at the patient interface.

25. A treatment apparatus with at least one surgical laser for the separation of a volume body of a human or animal eye, with at least one control device for the laser or lasers, and with a patient interface for docking to the eye, which is designed to perform the following method steps: determining a target position of the patient interface relative to the optical axis; positioning the patient interface in a preset area in front of the optical axis; illuminating the patient interface by means of an illumination device of the treatment apparatus; capturing a Purkinje image, which is associated with the patient interface, by means of an optical capturing device of the treatment apparatus; comparing the captured Purkinje image to the optical axis and determining the current position of the patient interface depending thereon; and comparing the current position to the target position and with a deviation of the current position from the target position, outputting a control signal to a control device of the treatment apparatus.

26. The treatment apparatus according to claim 25, wherein a first order or second order Purkinje reflex is captured as the Purkinje image.

27. The treatment apparatus according to claim 25, wherein with an ascertained deviation, a control signal is generated such that a position correction of the patient interface or of the optical axis is performed.

28. The treatment apparatus according to claim 25, wherein after an ascertained deviation below a preset deviation threshold value, a control signal is generated such that a docking procedure of the patient interface to the eye is performed.

29. The treatment apparatus according to claim 25, wherein said patient interface is illuminated by means of an illumination ring or illumination point or by means of an illumination half ring or by means of illumination sectors of the illumination device for generating the Purkinje image.

30. The treatment apparatus according to claim 25, wherein said patient interface is illuminated with infrared light by means of an infrared illumination device and the optical capturing device is configured such that infrared light reflected on the patient interface at least in certain areas is captured.

31. The treatment apparatus according to claim 25, wherein the patient interface is configured electrically insulated and/or sterile.

32. The treatment apparatus according to claim 25, wherein with a deviation above a preset deviation threshold value, the patient interface is newly positioned as the control signal.

33. The treatment apparatus according to claim 25, wherein with a deviation above a preset deviation threshold value, a position variation of the eye surgical laser, in particular of the laser beam, is performed.

34. The treatment apparatus according to claim 25, wherein the Purkinje image is captured by means of an optical capturing device arranged at the patient interface.

35. The treatment apparatus according to claim 25, wherein the control device comprises at least one storage device for at least temporarily storing at least one control dataset, wherein the control dataset or datasets include(s) control data for positioning and/or for focusing individual laser pulses in the cornea, and where-in the control dataset or datasets include(s) control data for positioning the patient interface; and includes at least one beam deflection device for beam guidance and/or beam shaping and/or beam deflection and/or beam focusing of a laser beam of the laser.

36. A computer program including commands that cause the treatment apparatus according to claim 25 to execute the method steps described therein.

37. A computer-readable medium having instructions stored thereon that, when executed by a processor, cause the processor to determine a current position of a patient interface of an eye surgical laser of a treatment apparatus for an eye of a patient relative to an optical axis of a laser beam of the laser in a neutral pose of a beam deflection device of the treatment apparatus, the processor: determining a target position of the patient interface relative to the optical axis; positioning the patient interface in a preset area in front of the optical axis; illuminating the patient interface by means of an illumination device of the treatment apparatus; capturing a Purkinje image, which is associated with the patient interface, by means of an optical capturing device of the treatment apparatus; comparing the captured Purkinje image to the optical axis and determining the current position of the patient interface depending thereon; and comparing the current position to the target position and with a deviation of the current position from the target position, outputting a control signal to a control device of the treatment apparatus.

38. The computer-readable medium of claim 37, wherein a first order or second order Purkinje reflex is captured as the Purkinje image.

39. The computer-readable medium of claim 37, wherein with an ascertained deviation, a control signal is generated such that a position correction of the patient interface or of the optical axis is performed.

40. The computer-readable medium of claim 37, wherein after an ascertained deviation below a preset deviation threshold value, a control signal is generated such that a docking procedure of the patient interface to the eye is performed.

41. The computer-readable medium of claim 37, wherein said patient interface is illuminated by means of an illumination ring or illumination point or by means of an illumination half ring or by means of illumination sectors of the illumination device for generating the Purkinje image.

42. The computer-readable medium of claim 37, wherein said patient interface is illuminated with infrared light by means of an infrared illumination device and the optical capturing device is configured such that infrared light reflected on the patient interface at least in certain areas is captured.

43. The computer-readable medium of claim 37, wherein the patient interface is configured electrically insulated and/or sterile.

44. The computer-readable medium of claim 37, wherein with a deviation above a preset deviation threshold value, the patient interface is newly positioned as the control signal.

45. The computer-readable medium of claim 37, wherein with a deviation above a preset deviation threshold value, a position variation of the eye surgical laser, in particular of the laser beam, is performed.

46. The computer-readable medium of claim 37, wherein the Purkinje image is captured by means of an optical capturing device arranged at the patient interface.

Description

[0024] The figures show the following.

[0025] FIG. 1 is a schematic representation of a treatment apparatus according to the invention.

[0026] FIG. 2 is a schematic side view of an embodiment of a treatment apparatus with a patient interface in a first situation.

[0027] FIG. 3 is a schematic top view to an eye of a patient.

[0028] FIG. 4 is a further schematic side view to an embodiment of the patient interface in a further situation.

[0029] FIG. 5 is a further schematic top view to an eye of a patient.

[0030] FIG. 6 is a further schematic side view to an embodiment of the patient interface in a further situation.

[0031] FIG. 7 is a further schematic top view to an eye of a patient in a further situation.

[0032] In the figures, identical or functionally identical elements are provided with the same reference characters.

[0033] FIG. 1 shows a schematic representation of a treatment apparatus 10 with an eye surgical laser 18 for the separation of a predefined corneal volume or volume body 12 with for example predefined interfaces 14, 16 of a cornea 13 (FIG. 2) of a human or animal eye 3 (FIG. 2) for example by means of photodisruption. One recognizes that a control device 20 for the laser 18 is formed besides the laser 18, such that it emits pulsed laser pulses in a predefined pattern into the cornea 13 in the present embodiment, wherein the interfaces 14, 16 of the volume body 12 to be separated are generated by the predefined pattern by means of photodisruption. In the illustrated embodiment, the interfaces 14, 16 form a lenticular volume body 12, wherein the position of the volume body 12 is selected in this embodiment such that a pathological and/or unnaturally altered area within a stroma 36 of the cornea 13 is enclosed. Furthermore, it is apparent from FIG. 1 that the so-called Bowman's membrane 38 is formed between the stroma 36 and an epithelium 28.

[0034] Furthermore, one recognizes that the laser beam 24 generated by the laser 18 is deflected towards a surface 26 of the cornea by means of a beam deflection device 22 such as for example a scanner. The beam deflection device 22 is also controlled by the control device 20 to generate the mentioned predefined pattern in the cornea. The beam deflection device 22 for example comprises two mirrors. The incident laser beam 24 can be rotated by rotation around a rotational axis. In a neutral pose of the mirrors, a so-called optical axis 4 (FIG. 2) of the laser beam 24 is in particular formed.

[0035] The illustrated laser 18 is a photodisruptive laser, which is formed to emit laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, at a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, and a repetition frequency of greater than 10 kHz, preferably between 100 kHz and 100 MHz. Alternatively to the treatment apparatus 10 shown in FIG. 1, a method for ablative removal of the volume body 12 can also be used.

[0036] In addition, the control device 20 comprises a storage device (not illustrated) for at least temporarily storing at least one control dataset, wherein the control dataset or datasets include(s) control data for positioning and/or for focusing individual laser pulses in the cornea 13. The position data and/or focusing data of the individual laser pulses are generated based on a previously measured topography and/or pachymetry and/or the morphology of the cornea and the pathological and/or unnaturally altered area 32 for example to be removed within the stroma 36 of the eye.

[0037] FIG. 2 purely exemplarily shows the treatment apparatus 10 in a first situation in a further schematic side view. The treatment apparatus 10 comprises a patient interface 2. The patient interface 2 is formed for the eye surgical laser 18 of the treatment apparatus 10 for the eye 3 of the patient not illustrated. The patient interface 2 can be coupled to the treatment apparatus 10 for example by means of a connection device 1 for guiding the patient interface 2.

[0038] In FIG. 2, it is shown that the patient interface 2 can for example have a distance to the eye 3 of for example 5 cm in the illustrated situation. Further, an iris 5 as well as a pupil 6 is shown at the eye 3 in FIG. 2.

[0039] In particular, a current pupil position 17 of the eye 3 can be additionally captured by means of the optical capturing device 9 for determining the current position.

[0040] FIG. 3 shows a view through the patient interface 2 to the eye 3 of the patient in a top view. In particular, the pupil 6 is shown hatched.

[0041] In the method for determining a current position of the patient interface 2, a target position of the patient interface 2 relative to the optical axis 4 of the laser beam 24 in the neutral pose of the beam deflection device 22 is determined. The patient interface 2 is positioned in a preset area in front of the optical axis 4. Illuminating the patient interface 2 by means of an illumination device 7 of the treatment apparatus 10 is effected. A Purkinje image 8, which is associated with the patient interface 2, is captured by means of an optical capturing device 9 of the treatment apparatus 10. Comparing the captured Purkinje image 8 to the optical axis 4 and determining the current position of the patient interface 2 depending thereon are effected. The current position is compared to the target position and with a deviation of the current position from the target position, a control signal is output to a control device 20 of the treatment apparatus 10.

[0042] In particular, FIG. 3 further shows that a static projection 11, in particular two static projections 11, are generated by the treatment apparatus 10, in particular by the illumination device 7, on the anterior surface of the patient interface 2. Further, the Purkinje image 8 is shown as a ring on the pupil 6, which is a static projection of the illumination device 7 on the anterior surface of the patient interface 2. Further, a dynamic projection ring 12a is shown, which is generated on an anterior surface of the cornea 13 of the eye 3, and can for example also be a Purkinje reflex on the cornea 13. Further, two dynamic projections 14a of the illumination device 7 are shown, which are generated on the anterior surface of the cornea 13.

[0043] In particular, it can be provided that a first order or second order Purkinje reflex is captured as the Purkinje image 8. Presently, a first order Purkinje reflex is in particular shown.

[0044] Further, the optical capturing device 9 can in particular be formed as a camera.

[0045] Further, it can be provided that with an ascertained deviation, a control signal is generated such that a position correction of the patient interface 2 or of the optical axis 4 is performed. Furthermore, it can be provided that after an ascertained deviation below a preset deviation threshold value, a control signal is generated such that a docking procedure of the patient interface 2 to the eye 3 is performed. The patient interface 2 can also be illuminated by means of an illumination ring or illumination point or by means of an illumination half ring or by means of illumination sectors as the illumination device 7 for generating the Purkinje image 8. Similarly, it can be provided that the patient interface 2 is illuminated with infrared light by means of an infrared illumination device as the illumination device 7 and the optical capturing device 9 is configured such that infrared light reflected on the patient interface 2 at least in certain areas is captured.

[0046] FIG. 4 shows the patient interface 2 in an approached state in a schematic side view, thus during an approaching procedure 18a to the eye 3. For example, as presently, a distance of the patient interface 2 to the eye 3 can be 2 to 3 mm. In particular, a Purkinje image 8 is shown on the eye 3. In particular, FIG. 4 shows the optical axis 4. For example, if a deviation above a preset deviation threshold value should now be ascertained, thus, the patient interface 2 can be newly positioned. Further, it can be provided that with a deviation above a preset deviation threshold value, a position variation of the eye surgical laser 18, in particular of the laser beam 24, is performed in that the beam deflection device 22 is for example positioned.

[0047] FIG. 5 shows the eye 3 in a further top view. In FIG. 5, the position of the patient interface 2 is in particular as it is illustrated in the side view in FIG. 4. In FIG. 5, a corresponding displacement and thus a deviation of the current position from the target position can in particular be registered. Based on this displacement, the control signal for the treatment apparatus 10, in particular for controlling the patient interface 2, can now be generated.

[0048] FIG. 6 shows the eye 3 in a schematic side view during the docking procedure of the patient interface 2. In particular, the patient interface 2 docks to a cornea apex 15 of the eye 3. In particular, the cornea apex 15 is displaced to the optical axis 4. In FIG. 6, it is in particular shown that the patient interface 2 is configured electrically insulated and/or sterile such that electrical voltages cannot transition from the patient interface 2 to the eye 3. In particular, germs either cannot be transferred from the patient interface 2 to the eye 3.

[0049] Further, FIG. 6 shows that the eye 3 is sucked onto and fixed to the patient interface 2 by means of a suction device 16a of the patient interface 2 after the docking procedure.

[0050] FIG. 7 shows the eye 3 with the patient interface 2 in the top view according to the side view of FIG. 6 in a schematic top view, wherein the Purkinje image 8 herein has nearly disappeared due to docking to the eye 3.