Treatment device and method for determining eye alignment

Abstract

The invention relates to a treatment device (10) and a method for determining the eye alignment of an eye (16).The treatment device (10) comprises at least one ophthalmic laser (12) for irradiating the eye (16) by means of laser radiation (20); a detection device (24) with at least one camera (26), wherein the detection device (24) is configured to capture eye image data by means of the at least one camera (26); and a computing device (18) configured to determine an eye orientation from the eye image data, wherein the eye orientation comprises a distance (3D), a vertical displacement (1D) and a horizontal displacement (2D) of the eye (16) relative to a predetermined reference point of the ophthalmic laser (12) as well as a cyclotorsion (6D), a vertical rotation (4D) and a horizontal rotation (5D) of the eye (16), wherein the computing device (18) is further configured to generate control data for controlling the treatment device (10) depending on the determined eye orientation.

Description

[0001] The invention relates to a treatment device for treating a human and / or animal eye. Furthermore, the invention relates to a method for determining the eye alignment of a human or animal eye, a computer program comprising commands that cause the treatment device to execute the method, and a computer-readable medium on which the computer program is stored.

[0002] Treatment devices and methods for controlling ophthalmic lasers to correct refractive errors and / or pathologically or abnormally altered areas of the cornea are known in the prior art. For example, pulsed lasers and a beam focusing device can be configured such that laser pulses cause photodisruption and / or ablation in a focus located within the organic tissue in order to remove tissue, in particular a tissue lenticel, from the cornea.

[0003] However, due to shifts in the eye's position relative to the laser's reference point, undesirable effects, particularly decentration and aberrations, especially chromatic aberrations, can occur during treatment. To center the eye for treatment, eye tracking systems or pupil tracking systems are used, which can detect translational shifts of the eye and compensate for them. However, conventional eye tracking systems do not capture all possible causes of eye decentration, which is why undesirable treatment effects can still occur despite compensation for a presumed translational shift.

[0004] Therefore, the object of the invention is to improve the detection of an eye's alignment for treatment with an ophthalmic laser.

[0005] This problem is solved by the independent patent claims. Advantageous embodiments of the invention are disclosed in the dependent patent claims, the following description, and the figures.

[0006] The invention is based on the idea of ​​determining eye alignment in six dimensions, whereby, in addition to translational displacements in the x, y, and z directions, a rotation of the eye in the x, y, and z directions is also determined in order to better identify the cause of decentering. In particular, distinguishing whether the eye is displaced due to translation or rotation can significantly contribute to compensating for the resulting effects.

[0007] One aspect of the invention relates to a treatment device for treating a human and / or animal eye. The treatment device comprises at least one ophthalmic laser for irradiating the eye with laser radiation, a detection device with at least one camera, wherein the detection device is configured to acquire eye image data using the at least one camera, and a computing device configured to determine an eye alignment from the eye image data, wherein the eye alignment comprises a distance, a vertical displacement, and a horizontal displacement of the eye relative to a predetermined reference point of the ophthalmic laser, as well as cyclotorsion, a vertical rotation, and a horizontal rotation of the eye. Furthermore, the computing device is configured to generate control data for controlling the treatment device depending on the determined eye alignment.

[0008] In other words, the treatment device designed to treat a human or animal eye may include at least one ophthalmic laser, in particular a photoablative and / or photodisruptive laser and / or a laser for generating a laser-induced refractive index change and / or a laser for increasing crosslinking of corneal tissue.

[0009] Furthermore, the treatment device can have at least one camera, preferably several cameras, which may be provided in a capture unit of the treatment device, wherein the camera is configured to capture eye image data of the eye. That is, the eye image data can comprise one or more images of the eye, which may be located in a treatment area on the treatment device. The eye image data can be captured in an optical or visible spectral range and / or an infrared spectral range.

[0010] A computing unit of the treatment device, which may be designed as a computer comprising one or more processors, particularly microprocessors, can then evaluate the eye scan data and determine the eye alignment. Preferably, the eye alignment is designed to include not only translational displacement in the x-direction (horizontal displacement), y-direction (vertical displacement), and z-direction (distance), but also rotations of the eye. Rotational displacement can be determined as cyclotorsion, i.e., rotation about a z-axis, which may pass through the reference point of the laser, as well as tilts or rotations of the eye along an arc in the x-direction (vertical rotation) and y-direction (horizontal rotation).

[0011] To detect rotational movement, several strategies can be used to analyze eye scan data. Firstly, landmarks or predefined structures within the eye can be identified. Based on changes in the appearance of these landmarks or structures in the captured eye scan data, it is possible to distinguish whether a displacement or decentering is due to rotation or translation of the eye. For example, to identify these landmarks, a diagnostic image of the eye with a known eye orientation can be used. The landmarks in the diagnostic image can then be compared with the eye scan data from the acquisition device to determine the change. Circular structures, such as the pupillary margin or the limbus (the transition from the iris to the sclera), have proven to be particularly suitable landmarks.For example, if these circular structures appear elliptically or ovally deformed in the eye scan data, a rotation may be present. However, if the structure retains its circular shape but lies outside the center of the reference point, then only a translational displacement may be present. The reference point can preferably be a point in or on the eye, such as a corneal vertex and / or the center of the pupil. Alternatively or additionally, the reference point can also be the neutral or zero position of the laser.

[0012] As another strategy for determining eye orientation, the scanning device can have multiple cameras capable of capturing the eye from different directions. This means that the cameras can be aligned with the eye at different known angles. Based on the eye image data captured from these different directions, it is then possible to infer rotation and / or translation of the eye.

[0013] As a further strategy for determining eye alignment, the treatment device, in particular the detection device, can also include a projection unit that can emit a light signal with a predefined projection pattern onto the eye, whereby a reflection of the projection pattern can be captured by the camera. Depending on any deformation of the captured reflection of the projection pattern, a translation and / or rotation of the eye can then be calculated.

[0014] The determined eye alignment can then be used to generate control data for controlling the treatment device or to adjust predetermined control data, in particular by adapting originally planned irradiation positions to the determined eye alignment. The control data can include a data set for positioning and / or focusing individual laser pulses in the cornea. Additionally or alternatively, the control data can include a data set for adjusting at least one beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam from the respective laser.

[0015] The invention offers the advantage of enabling better treatment results.

[0016] The invention also includes further developments that result in additional advantages.

[0017] A further development provides that the acquisition device includes a projection unit configured to emit a projection pattern, and the computing device is configured to determine the eye orientation based on the projection pattern captured in the eye scan data. Preferably, the projection pattern can be a striped pattern or grid pattern with predetermined spacing between the stripes. In other words, a known projection pattern can be emitted onto the eye by a projection unit (projector), and the acquisition device can detect any reflection of the projection pattern reflected by the eye. If a striped pattern is used, the distance to the projection unit, and thus the distance of the eye to the reference point, can be determined based on the spacing between the stripes.Furthermore, rotation in the horizontal and / or vertical direction can be determined by varying the distances. For example, if the distance on one side of the projection pattern becomes greater than on the other when the fringes are reflected, rotation may be present. This can preferably be used in conjunction with a recorded pupil position or limbus center to determine the translational and rotational components. This advanced technique offers the advantage of improved determination of eye rotation.

[0018] A further development provides that the acquisition device has at least two cameras arranged to capture eye image data from different angles. This means that the acquisition device has at least two cameras, preferably more than two, designed and arranged to capture the eye from multiple directions or angles. From the resulting volume information, a translation and / or rotation of the eye relative to the reference point can then be determined. For example, if the eye is decentered in the image captured by one camera and centered in the image captured by the other camera, a rotation in the corresponding direction of the camera can be inferred. This development offers the advantage of a more precise determination of eye orientation, which improves the provision of control data.

[0019] Alternatively or additionally, the camera is designed as a plenoptic camera. The plenoptic camera, also known as a light field camera, can detect the direction of the incident light rays in addition to the usual two image dimensions, from which information about the image depth can be determined. Consequently, the eye orientation can be determined from eye-tracking data acquired with the plenoptic camera.

[0020] A further development involves predetermining ocular landmarks, with the computing device designed to determine eye orientation based on the position of these landmarks in the eye scan data. A landmark could be, for example, the pupil's center, allowing for the determination of horizontal and / or vertical displacement. Alternatively, a structure of the iris could be predetermined, enabling the calculation of cyclotorsion. Furthermore, circular structures within the eye, particularly the limbus, could be used as landmarks to determine eye rotation and / or distance.For example, a predetermined diameter of the eye's limbus can be compared with a diameter of the limbus in the eye scan data to determine the distance of the eye to the treatment device, whereby the diameter or radius increases with decreasing distance. To determine rotation in the vertical and / or horizontal direction, it can be checked whether the circular structure, in particular the limbus, exhibits an elliptical shape in the eye scan data. Depending on the shape of the resulting ellipse, the direction and / or angle of rotation can be provided. In particular, the pupil position or the position of a limbus center, in combination with the deformation of the limbus and / or the pupil in the eye scan data, can thus be used to deduce the translational and rotational components of the eye.This advanced training offers the advantage that eye alignment can be determined using predetermined structures or landmarks of the eye and only one camera.

[0021] Further development involves the computer being configured to monitor the centering of the eye on a contact element of the treatment device using the control data. This means that the approach of the eye to a contact element can be monitored, with the control data being used to output signals if the eye is decentered due to translation and / or rotation. In particular, the control data can be used to initiate a fixation device for automatically fixing the eye if the centering meets a predefined centering condition in both the translational and rotational directions.

[0022] Further training involves equipping the computer system to adjust the laser beam positions of the ophthalmic laser using control data, particularly during treatment. This means that the originally planned treatment positions can be adjusted based on the current eye alignment, ensuring that the planned positions are irradiated even in cases of eye decentration. This can improve treatment outcomes.

[0023] Another aspect of the invention relates to a method for determining the eye alignment of a human and / or animal eye for a treatment device with an ophthalmic laser. This method involves capturing eye image data from a detection device comprising at least one camera. A computing device then determines the eye alignment from these eye images. The eye alignment is defined as the distance, vertical displacement, and horizontal displacement of the eye relative to a predetermined reference point of the ophthalmic laser, as well as the cyclotorsion, vertical rotation, and horizontal rotation of the eye. Finally, the computing device generates control data for controlling the treatment device based on the determined eye alignment. This method offers the same advantages and possibilities for variation as the treatment device itself.

[0024] The procedure may include at least one additional step that is executed precisely when a use case or application situation occurs that is not explicitly described here. This step may, for example, include the output of an error message and / or a prompt for user feedback. Additionally or alternatively, it may include setting a default value and / or a predetermined initial state.

[0025] Another aspect concerns a computing device or a control device configured to perform the steps of at least one embodiment of one or both of the previously described methods. For this purpose, the computing device may include a computing unit for electronic data processing, such as a processor. The computing unit may comprise at least one microcontroller and / or at least one microprocessor. The computing unit may be implemented as an integrated circuit and / or microchip. Furthermore, the control device may include an (electronic) data storage device or a storage unit. Program code, which encodes the steps of the respective embodiment of the method, may be stored on the data storage device. The program code may include the control data for the respective laser.The program code can be executed by the processing unit, which then causes the computing device to execute the respective implementation. The computing device can be designed as a control chip or control unit. The computing device can, for example, be part of a computer or computer network.

[0026] Another aspect of the invention relates to a computer program. The computer program comprises instructions that, for example, constitute program code. The program code can include at least one control data set with the respective control data for the respective laser. When the program code is executed by a computer or a computer network, it is caused to execute the method described above, or at least one embodiment thereof.

[0027] Another aspect of the invention relates to a computer-readable medium (storage medium) on which the aforementioned computer program or its instructions are stored. To execute the computer program, a computer or a computer network can access the computer-readable medium and read its contents. The storage medium is, for example, designed as a data storage device, in particular at least partially as a volatile or non-volatile data storage device. A non-volatile data storage device can be flash memory and / or an SSD (solid-state drive) and / or a hard drive. A volatile data storage device can be RAM (random access memory). The instructions can be, for example, in the form of source code of a programming language and / or as assembly language and / or as binary code.

[0028] Further features and advantages of one of the described aspects of the invention may arise from further developments of another aspect of the invention. The features of the embodiments of the invention can therefore exist in any combination with one another, unless they have been explicitly described as mutually exclusive.

[0029] Additional features and advantages of the invention are described below with reference to the figure(s) in the form of advantageous embodiments. The features or combinations of features of the embodiments described below can be combined with each other and / or with the features of the embodiments. That is, the features of the embodiments can complement and / or replace the features of the embodiments, and vice versa. Therefore, embodiments that are not explicitly shown or explained in the figures, but which can be derived and generated from separate combinations of features in the embodiments and / or embodiments, are also to be considered as encompassed and disclosed by the invention.Thus, embodiments that do not exhibit all the features of an originally formulated claim, or that go beyond or deviate from the combinations of features set forth in the cross-references of the claims, are also to be considered disclosed. For exemplary embodiments, see: Fig. 1 a treatment device according to an exemplary embodiment; Fig. 2 a treatment device according to a further exemplary embodiment; Fig. 3 a treatment device according to a further exemplary embodiment; Fig. 4. A representation of the eye orientations of one eye.

[0030] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0031] The Fig. Figure 1 shows a schematic representation of a treatment device 10 with an ophthalmic laser 12 for removing tissue 14 from a human or animal eye 16, in particular a cornea, by means of photodisruption and / or ablation. The tissue 14 can, for example, be a lenticule or a volumetric body that can be removed from the cornea of ​​the eye 16 with the laser 12 to correct a refractive error. A correction profile or a geometry of the tissue 14 to be removed can be provided by a computing unit 18 or control unit, in particular in the form of control data, so that the laser 12 emits pulsed laser pulses into the cornea of ​​the eye 16 in a pattern predefined by the control data in order to remove the tissue 14. Alternatively, the computing unit 18 can be an external computing unit 18 with respect to the treatment device 10.

[0032] Furthermore, the Fig. 1. The laser beam 20 generated by the laser 12 can be deflected towards the eye 16 by means of a beam deflection device 22, such as a rotary scanner, in order to remove the tissue 14. The beam deflection device 22 can also be controlled by the computer 18 to remove the tissue 14.

[0033] The laser 12 shown is preferably a photodisruptive and / or photoablative laser configured to emit laser pulses in a wavelength range between 300 nanometers and 1400 nanometers, preferably between 700 nanometers and 1200 nanometers, with a pulse duration between 1 femtosecond and 1 nanosecond, preferably between 10 femtoseconds and 10 picoseconds, and a repetition frequency greater than 10 kilohertz, preferably between 100 kilohertz and 100 megahertz. The computing device 18 optionally also includes a storage device (not shown) for at least temporarily storing at least one control data set, wherein the control data set(s) comprise control data for positioning and / or focusing individual laser pulses in the cornea.

[0034] In order for predetermined treatment positions in the eye 16 to be targeted by the laser beam 20, the eye's orientation relative to a reference point of the laser must correspond to a predetermined eye orientation, or the eye orientation relative to the reference point must be known or determinable in order to direct the laser beam 20 to the corresponding treatment positions by means of the beam deflection device 22. To determine the eye orientation of the eye 16, the treatment device 10 can include a detection device 24. The detection device 24 can include at least one camera 26 that captures images of the eye 16 in a visible and / or infrared spectral range and provides them as eye image data to the computing device 18.

[0035] The computing unit 18 can further be configured to evaluate the eye image data and thus provide, as eye alignment, a distance, a vertical displacement, and a horizontal displacement of the eye 16 relative to the reference point, which can be defined by a neutral position of the beam deflection device 22. Furthermore, the computing unit 18 can be configured to determine, using the eye image data, a cyclotorsion, that is, a rotation of the eye 16 about a defined axis of the laser beam 20 in the neutral position of the beam deflection device 22, as well as a vertical rotation and a horizontal rotation of the eye 16.

[0036] The eye alignment for eye 16 with the corresponding directions is shown, for example, in Fig. Figure 4 illustrates this. A first dimension is provided by a horizontal displacement (1D), a second dimension by a vertical displacement (2D), and a third dimension by a distance or lateral displacement (3D), which together provide a translational displacement of the eye 16 relative to the treatment device 10 or the reference point. Furthermore, a horizontal rotation (4D), a vertical rotation (5D), and a cyclotorsion (6D) can provide a total of six-dimensional orientation of the eye 16 in space, which can be determined from the eye images by the computing unit 18.

[0037] In order for the computing device 18 to determine these six dimensions from the recording data, if only one camera 26 is available, a structure of the eye, in particular landmarks of the eye, can be predefined, whereby these can be determined in the eye images. The landmarks determined in the eye images, in particular a position and / or a distortion / shear, can then be compared with the position and / or distortion / shear of the predetermined landmarks, and it can be checked whether and to what extent they differ from each other. Using this deviation, the eye alignment can then be determined. In particular, a limbus can be measured in the eye image data, preferably a radius or diameter at least in the horizontal and vertical directions.This can then be compared with the predetermined landmarks of the limbus to determine how far eye 16 is from the treatment device and whether a rotation is present in a horizontal or vertical direction. For example, if the radius is smaller in all spatial directions than that of the predetermined landmarks, eye 16 is located further from the reference point. If a rotation is present, the radius can change in the corresponding direction, meaning that the originally circular limbus is represented as an ellipse or oval in the eye scan data. Based on this deformation, the eye rotation in the corresponding direction can then be deduced.

[0038] After the computing unit 18 has determined the eye alignment in the six dimensions, it can generate control data for controlling the treatment device 10, compensating for any deviation from an optimized eye alignment. In particular, the control data can actuate the beam deflection device 22 such that the laser beam 20 is aligned to the originally planned irradiation positions. This can preferably also be performed during the treatment, during which the eye alignment can be monitored in real time by the detection device 24.

[0039] In Fig. Figure 2 shows another exemplary embodiment of the treatment device 10. In this embodiment, the detection device 24 can have at least two cameras 26 that capture images of the eye 16.

[0040] The cameras 26 of the detection device 24 can be aligned with the eye 16 at different predefined angles in order to record the eye 16 from different positions. Preferably, additional cameras with further angles can be provided. Due to the different recording angles of the eye 16, the computing device 18 can thus determine depth information, which can be used to ascertain the eye orientation in the six dimensions.

[0041] In Fig. Figure 3 shows another exemplary embodiment of the treatment device 10. In this embodiment, the detection device 24 for determining the eye orientation may include, in addition to the camera 26, a projection unit 28, which may be configured to emit a light pattern or projection pattern onto the eye 16. The projection pattern may preferably be a line or grid pattern with a predetermined distance between the respective lines. From a reflection of this projection pattern, which can be detected by the camera 26, the computing unit 18 can determine the distance of the eye 16 as well as vertical or horizontal rotations. Translation and cyclotorsion can then, for example, be additionally determined based on landmarks in the eye 16, in particular based on a pattern of the iris of the eye 16, and / or a pupil position.To determine the vertical and horizontal rotation, the distance between the lines or stripes can be checked, whereby when the eye rotates, the lines have larger distances in the direction of rotation.

[0042] The features of the embodiments described in the Fig. The steps described in points 1 to 3 can also be combined to enable improved determination of eye alignment.

[0043] Overall, the examples show how the invention can be used to determine eye alignment in six dimensions.

Claims

[1] Treatment device (10) for treating a human and / or animal eye (16), comprising: - at least one ophthalmological laser (12) for irradiating the eye (16) by means of laser radiation (20); - a detection device (24) with at least one camera (26), wherein the detection device (24) is designed to detect eye recording data by means of the at least one camera (26); and - a computing device (18) designed to determine an eye alignment from the eye recording data, wherein the eye alignment comprises a distance (3D), a vertical displacement (1D) and a horizontal displacement (2D) of the eye (16) relative to a predetermined reference point of the ophthalmic laser (12) as well as a cyclotorsion (6D), a vertical rotation (4D) and a horizontal rotation (5D) of the eye (16), - wherein the computing device (18) is further designed to generate control data for controlling the treatment device (10) as a function of the determined eye alignment. [2] Treatment device (10) according to claim 1, wherein the detection device (24) comprises a projection unit (18) which is designed to emit a projection pattern, wherein the computing device (18) is designed to determine the eye alignment as a function of the projection pattern detected in the eye recording data. [3] Treatment device (10) according to claim 2, wherein the projection pattern is a stripe pattern with predetermined distances between the stripes. [4] Treatment device (10) according to one of the preceding claims, wherein the detection device (24) has at least two cameras (26) arranged to record the eye recording data from different angles. [5] Treatment device (10) according to one of the preceding claims, wherein landmarks of the eye (16) are predetermined, wherein the computing device (18) is designed to determine the eye alignment as a function of a position of the landmarks in the eye recording data. [6] Treatment device (10) according to one of the preceding claims, wherein the computing device (18) is designed to monitor a centering of the eye (16) on a contact element of the treatment device (10) using the control data. [7] Treatment device (10) according to one of the preceding claims, wherein the computing device (24) is designed to adapt irradiation positions of the laser beam (20) of the ophthalmological laser (12) with the control data, in particular during a treatment. [8] Method for determining an eye alignment of a human and / or animal eye (16) for a treatment device (10) with an ophthalmic laser (12), wherein eye recording data of the eye (16) are recorded by a recording device (24) which comprises at least one camera (26), wherein an eye alignment is determined from the eye recordings by a computing device (18), wherein a distance (3D), a vertical displacement (1D) and a horizontal displacement (2D) of the eye (16) relative to a predetermined reference point of the ophthalmic laser (12) as well as a cyclotorsion (6D), a vertical rotation (4D) and a horizontal rotation (5D) of the eye (16) are determined as the eye alignment, wherein control data for controlling the treatment device (10) are generated by the computing device (18) as a function of the determined eye alignment. [9] A computer program comprising instructions that cause a treatment device (10) to carry out a method according to claim 8. [10] A computer-readable medium on which a computer program according to claim 9 is stored.

Images