Method for monitoring an eye during treatment with an ophthalmic laser of a treatment device

Abstract

The invention relates to a method for monitoring an eye during treatment with an ophthalmic laser of a treatment device, wherein the treatment device has a recording device with at least two cameras, wherein a first camera is coaxially and a second camera is non-coaxially aligned to an eye contact area of ​​the treatment device.The method comprises the following steps: capturing the eye at the eye contact area using recording data of the eye, which is recorded by at least one of the two cameras of the recording device; in the event of impairment of the recording data from one of the two cameras, the capture of the eye is continued by the other unimpaired of the two cameras; wherein a coordinate system of the first camera is linked to a coordinate system of the second camera by a predetermined transformation matrix, such that the coordinate systems of the at least two cameras are registered to each other.

Description

[0001] The invention relates to a method for monitoring an eye during treatment with an ophthalmic laser and a treatment device. Furthermore, the invention relates to a treatment device comprising at least one ophthalmic laser and a recording device.

[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] Furthermore, monitoring the eye during treatment using an "eye tracker" is known, whereby an "eye tracker" typically has a camera that records the eye's position or orientation. However, it can happen that the eye tracker's camera is impaired, for example, if the eye leaves the camera's field of view, at least partially, or if the camera's field of view is at least partially obscured, for example, by a contact element of the treatment device.

[0004] From DE 10 2019 219 122 A1, a positioning device is known which has a first and a second recording unit that provide recording data from different recording directions, as well as a displacement unit for shifting the relative position of the eye relative to an optical opening of the laser therapy system based on control commands and a control unit that is configured to generate control commands based on the recording data.

[0005] Therefore, the object of the invention is to improve the monitoring of an eye during treatment with a treatment device.

[0006] 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.

[0007] The invention is based on the idea that a recording device for capturing images of the eye comprises at least two cameras, one of which is coaxially aligned with an eye contact area, as is conventional, and the second of which is non-coaxially aligned. This means that the second camera is angled towards the eye, providing an additional field of view. If the recording data from one camera is affected, for example, because one of the fields of view is obscured or because the eye is outside the field of view of one of the cameras, the other camera can continue monitoring the eye. To ensure that the recordings from both cameras provide the same information, for example, to monitor the placement of laser pulses, the coordinate systems of the cameras are linked using a predetermined transformation matrix, so that the coordinate systems are registered with each other.Preferably, the coordinate system registered against each other corresponds to the coordinate system of the ophthalmic laser.

[0008] One aspect of the invention relates to a method for monitoring an eye for treatment with an ophthalmic laser of a treatment device, wherein the treatment device has a recording device with at least two cameras, wherein a first camera is coaxially and a second camera is non-coaxially aligned to an eye contact area of ​​the treatment device.The method comprises the following steps: capturing the eye at the eye contact area using recording data of the eye, which is recorded by at least one of the two cameras of the recording device, wherein if the recording data from one of the two cameras is impaired, the capturing of the eye is continued by the other unimpaired of the two cameras, wherein a coordinate system of the first camera is linked to a coordinate system of the second camera by a predetermined transformation matrix, such that the coordinate systems of the at least two cameras are registered to each other.

[0009] In other words, the treatment device includes a recording device comprising at least two cameras. A first camera is coaxially aligned with an eye contact area. That is, the first camera is pointed directly at the eye, which may be located within the eye contact area, so that the first camera records the eye from the front. The second camera can be angled towards the eye contact area, so that the second camera records the eye from a lateral perspective. Furthermore, additional cameras may be provided, each aligned at a different angle to the eye contact area.

[0010] The cameras can be registered to each other using a transformation matrix, which can describe translation, rotation, and / or scaling, so that the coordinate systems of the respective cameras coincide. Furthermore, the coordinate system to which the cameras are registered can coincide with a coordinate system of the ophthalmic laser. Thus, a pixel from one of the cameras can be easily correlated with the irradiation positions of the ophthalmic laser.

[0011] The method may involve capturing the eye at the eye contact area using at least two cameras, with both cameras being able to simultaneously record the eye from different angles. If the recording data from one of the two cameras is impaired, monitoring of the eye can continue with the unaffected camera. The two cameras can preferably be arranged such that different fields of view are provided, so that if one camera is impaired, the other has an unaffected field of view. The field of view or the recording data can be impaired, for example, if the eye is at least partially obscured by an element of the treatment device, in particular by a contact element that may be located in the eye contact area.Alternatively, the eye may be shifted or rotated relative to the field of view of one of the cameras, so that the eye is not fully captured in the recording data.

[0012] This procedure can be performed, for example, during treatment preparation, when the eye is brought close to the eye contact area and its alignment with the ophthalmic laser is adjusted, particularly to align planned treatment coordinates with the eye's current orientation. Furthermore, the procedure can be performed during treatment monitoring, especially to check for eye movement during the procedure.

[0013] The eye contact area can be a region of the treatment device where the eye is to be positioned for laser irradiation. That is, a laser beam from the ophthalmic laser can be emitted from the treatment device in the eye contact area. Preferably, a fixation device, such as a contact element or a suction device, can be provided in the eye contact area to hold the eye in a treatment position.

[0014] The invention offers the advantage that eye monitoring can take place in multiple dimensions and degrees of freedom, enabling better centering and / or correction of astigmatism or asymmetrical aberrations. In particular, eye monitoring can continue even if the camera's image data is compromised, thereby improving the monitoring process.

[0015] Furthermore, according to the invention, impairment of a camera's recording data is determined by means of an image analysis algorithm. The image analysis algorithm can, for example, be trained using images of unimpaired eyes, that is, images in which the eye is fully visible. If the eye is only partially visible in an image, or partially obscured, the image analysis algorithm can detect an impairment. In this context, the image analysis algorithm can, for example, be based on artificial intelligence that has been trained using the aforementioned images. This offers the advantage that it is possible to automatically identify which camera is providing impaired recording data and which camera is providing unimpaired recording data.

[0016] The invention also includes embodiments that offer additional advantages.

[0017] One embodiment involves performing an affine transformation using the transformation matrix. This means that image points from the coordinate system of a camera can be adapted by a geometric transformation that linearly shifts, scales, and / or rotates the image points in a vector space.

[0018] Another embodiment provides that the first camera is used as the main camera for capturing the recording data, and the second camera is used as a backup camera only if the recording data from the first camera is compromised. This means that the coaxial camera can preferably be used for monitoring the eye and thus serves as the main camera. If the recording data from the main camera is compromised, for example, by partial obstruction of the eye, the system can switch to the non-coaxial backup camera to continue monitoring. This can occur, in particular, during an approach process to align the eye with the eye contact area, shortly before the eye touches the eye contact area or a contact element located thereon.In this position, just in front of the contact element, the recording data from the first camera can be affected because the contact element can partially obscure the eye. In this situation, the system can switch to the second camera as a backup, which will record the unaffected data.

[0019] Another embodiment provides that the treatment device has a contact element with a suction device, wherein the recording data is captured by the unaffected camera upon contact with the contact element, but without fixation by the suction device. For example, the suction device may partially obscure a field of view of the first camera, thereby affecting this recording data. In this case, the recording data can be captured by the second camera, which is arranged non-coaxially, upon contact with the suction device. It may be provided that no fixation by the suction device occurs at this stage, since the unaffected recording data allows for further correction and alignment of the eye before the suction device fixes the eye in a position.

[0020] Another embodiment provides that the treatment device has a contact element with a suction device, wherein the image data is captured by the unaffected camera upon contact with the contact element and fixation by the suction device. The final treatment position can then be determined from the image data of the unaffected camera, whereby, for example, planned treatment coordinates from a diagnostic image can be converted into the image data of the unaffected camera.

[0021] Another embodiment provides that the recording device captures the eye's image data using different lighting conditions and / or different wavelengths. This allows, for example, the eye to be captured in the visible or infrared wavelength range.

[0022] Another embodiment provides that additional planned treatment coordinates for the treatment of the eye are provided from predetermined diagnostic data of the eye. This involves determining a treatment coordination matrix between a coordinate system of the diagnostic data and a coordinate system of the unaffected camera, based on image data of the eye acquired by the unaffected of the two cameras. The treatment coordinates are then adapted using this determined treatment coordinate transformation matrix. Subsequently, control data for controlling the ophthalmic laser and / or the treatment device can be provided, including the adapted treatment coordinates. The control data can include a data set for positioning and / or focusing individual laser pulses in the cornea.The control data may additionally or alternatively include a data set for setting at least one beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam of the respective laser. For example, these steps can be performed by a control unit of the treatment device. A difference between the coordinate system of the diagnostic image and the unaffected camera can be determined, for example, using predetermined reference points in or on the eye, from which the treatment coordinate transformation matrix can be derived. Using the treatment coordinate transformation matrix, the treatment coordinates can preferably be adapted to the coordinate system of the first camera, which is coaxially aligned, wherein the coordinate system of the first camera may preferably coincide with a coordinate system of the ophthalmic laser.In particular, it can be provided that the treatment coordinates are adapted to the coordinate system of the second camera by the treatment coordinate transformation matrix, and these can then be transformed by the transformation matrix to the coordinate system of the first camera, which can correspond to a coordinate system of the ophthalmic laser. In other words, this embodiment allows corrections to be derived from diagnostic data serving as a reference, with corresponding treatment positions then being transformed into a coordinate system of the unaffected camera used to monitor the treatment. Thus, a treatment can be improved if the eye is not recorded in the same orientation as during treatment planning.

[0023] Another embodiment provides that during laser pulse treatment of the eye, at least one irradiated position of the eye is recorded by the unaffected camera, wherein the recording data from the unaffected camera is transformed by a treatment coordinate transformation matrix into a coordinate system of predetermined diagnostic data, such that the at least one irradiated position of the eye is assigned to a corresponding planned treatment coordinate. In other words, irradiated positions can be recorded by the unaffected camera, and each irradiated position can be transformed by the treatment coordinate transformation matrix into the coordinate system of the diagnostic data in order to determine which planned treatment coordinate was irradiated.Based on the diagnostic data, it can then be determined which subsequent treatment coordinate should be irradiated, whereby the laser can be controlled according to the transformed coordinate system. This means that the acquisition data and the diagnostic data can function as a control loop to set a subsequent irradiation position for the ophthalmic laser. Thus, after determining an irradiated position and transforming it into the coordinate system of the diagnostic data, it can be determined which depth and / or xy-position should be irradiated next.

[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] A further aspect of the invention relates to a treatment device with at least one ophthalmic laser and a recording device, wherein the recording device has at least two cameras, wherein a first camera is coaxially and a second camera is non-coaxially aligned to an eye contact area of ​​the treatment device, wherein the recording device is configured to acquire recording data of the eye by at least one of the two cameras and, in the event of impairment of the recording data from one of the two cameras, to continue acquiring the recording data of the eye by the other unimpaired of the two cameras, wherein a coordinate system of the first camera is linked to a coordinate system of the second camera by a predetermined transformation matrix, such that the coordinate systems of the at least two cameras are registered with each other, wherein the treatment device has a control device configured toTo determine impairment of a camera's recording data using an image analysis algorithm. This offers the same advantages and variations as the previous method.

[0026] Furthermore, the treatment device can include a control unit configured to perform the steps of at least one embodiment of the previously described method. For this purpose, the control unit can include a computing unit for electronic data processing, such as a processor. The computing unit can comprise at least one microcontroller and / or at least one microprocessor. The computing unit can be implemented as an integrated circuit and / or microchip. The control unit can also include an (electronic) data storage device or a storage unit. Program code encoding the steps of the respective embodiment of the respective method can be stored on the data storage device. The program code can include the control data for the respective laser.The program code can be executed by the processing unit, which then causes the control unit to execute the respective configuration. The control unit can be designed as a control chip or control device. The control unit can, for example, be part of a computer or computer network.

[0027] Another aspect concerns a computer program. A computer program comprises instructions that, for example, constitute program code. When the program code is executed by a computer or a computer network, it is instructed to execute the previously described method, or at least one embodiment thereof.

[0028] Another aspect concerns 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, a data storage device, in particular at least partially 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.

[0029] 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.

[0030] 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 schematic representation of a treatment device according to an exemplary embodiment; Fig. 2 a schematic process diagram for a process according to an exemplary embodiment.

[0031] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0032] The Fig. Figure 1 shows a schematic representation of a treatment device 10 with an ophthalmic laser 12 for removing tissue 14 from an eye 16, in particular from the cornea of ​​the eye 16, 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 eye 16 with the ophthalmic 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 control device 18, in particular in the form of control data, so that the laser 12 emits pulsed laser pulses into the eye 16 in a pattern predefined by the control data in order to remove the tissue 14. Alternatively, the control device 18 can be an external control device 18 with respect to the treatment device 10.

[0033] 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 control device 18 to remove the tissue 14.

[0034] 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 control 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.

[0035] Furthermore, the treatment device 10 can include a recording device 24 for monitoring the eye 16. The recording device 24 can, for example, be used to check the alignment of the eye 16 before treatment, in particular to assign planned treatment coordinates, which can be provided from predetermined diagnostic data, to a determined alignment of the eye 16. Alternatively or additionally, the recording device 24 can monitor treatment of the eye 14 and automatically adjust irradiation positions according to the alignment of the eye 16.

[0036] The recording device 24 can comprise at least a first camera 26 and a second camera 28, and further cameras are also possible, which are not shown here for the sake of clarity. The first camera 26 can be arranged coaxially with respect to an eye contact area 30. That is, the first camera 26 can be aligned directly with the eye 16, or the first camera 26 can be arranged parallel to the path of the laser beam 20, which is in a zero position (no deflection of the laser beam in the x / y direction) of the beam deflection device 22. The second camera 28 can be arranged non-coaxially and thus be aligned obliquely with respect to the eye contact area 30 and the eye 16. That is, the second camera 28 can be arranged at a different angle than the first camera 26.The eye contact area 30 can be an area on the treatment device 10 in which the eye 16 is to be placed for treatment with the treatment device 10. For example, a contact element (not shown) and / or a suction device (not shown) can also be provided in the eye contact area 30 to hold the eye 16 in position.

[0037] Furthermore, a transformation matrix is ​​provided for the first camera 26 and the second camera 28, with which the coordinate systems of the two cameras 26 and 28 are registered to each other. This means that, using the transformation matrix, a pixel from the recording data of the first camera 26 can be transformed to the same pixel from the recording data of the second camera 28, which, however, was recorded from a different perspective due to the different orientations of the cameras 26 and 28.

[0038] This design of the recording device 24 makes it possible to capture recording data of the eye 16 even if the recording data from one of the two cameras is obstructed. In particular, when approaching the eye contact area 30, it can happen that a portion of the first camera 26's view of the eye 16 is partially obscured and thus impaired.

[0039] For example, a contact element or suction device in the eye contact area 30 may obstruct the field of view of one of the cameras 26, 28. To continue monitoring the eye 16, the second camera 28 can be positioned so that the recording data from the second camera 28 in the eye contact area 30 is unaffected. However, the reverse is also possible: the recording data from the second camera 28 may be obstructed, and the first camera 26 may then provide unobstructed recording data.

[0040] In an exemplary situation, the first camera 26 may be used as the main camera for capturing the recording data, particularly when the eye 16 approaches and aligns itself with the eye contact area 30. During this process, the recording data from the first camera 26 may be partially affected. If the impairment is detected, for example by an image analysis algorithm, the second camera 28 can continue to capture the recording data as a backup camera. The recording data can be captured under different lighting conditions and / or at different wavelengths.

[0041] Furthermore, it can be provided that planned treatment coordinates for the treatment of eye 16 are generated from predetermined diagnostic data, whereby the image data of eye 16, acquired by the unaffected of the two cameras, for example, by the second camera 28, can be transformed between the coordinate system of the diagnostic image and the coordinate system of the second camera 28 using a predetermined treatment coordinate transformation matrix. Thus, the planned treatment coordinates can be transformed from the image data of the second camera 28 to the captured orientation of eye 16 in order to adapt it for treatment.Treatment can also be monitored using the cameras 26, 28 of the recording device 24, whereby already irradiated positions can be converted into the coordinate system of the diagnostic image using the treatment coordinate transformation matrix in order to assign the already irradiated positions to planned treatment coordinates. This allows verification of which of the planned treatment coordinates have already been irradiated and which setting the laser 12 or the beam deflection device 22 should assume for a subsequent irradiation position.

[0042] In Fig.2 is a method for monitoring an eye 16 for treatment with an ophthalmic laser 12 of a treatment device 10, wherein the treatment device 10 has a recording device 24 with at least two cameras 26, 28, wherein the first camera 26 is coaxially and the second camera 28 is non-coaxially aligned to an eye contact area 30 and coordinate systems of the two cameras are linked to each other by a predetermined transformation matrix, such that the two cameras 26, 28 are registered to each other.

[0043] In step S10, the eye 16 can be recorded at the eye contact area 30 by the recording device 24, in particular simultaneously by the first camera 26 and the second camera 28.

[0044] If, in step S12, one of the two cameras 26, 28 is impaired, for example by a partial obstruction of its field of view or by the eye 16 partially leaving its field of view, the monitoring of eye 16 can continue with the unaffected of the two cameras 26, 28. For example, recording data from the first camera 26 may be impaired. In this case, in step S12, the second camera 28 can continue acquiring the recording data, which can still be provided in the same coordinate system due to the transformation matrix. Alternatively, the recording data from the second camera 28 may also be impaired, and the first camera 26 can continue acquiring the recording data.

[0045] Optionally, in step S14, planned treatment coordinates for the treatment of eye 16 can be provided from predetermined diagnostic data of eye 16. Using the image data of eye 16, which can be acquired by the unaffected of the two cameras 26, 28, the planned treatment coordinates can then be transformed from a coordinate system of the diagnostic data to a coordinate system of the unaffected camera using a predetermined treatment coordinate transformation matrix. This transforms the treatment coordinates from the diagnostic data to the orientation captured from the image data of the unaffected camera.

[0046] Optionally, in a subsequent step, control data S16 can be generated for controlling the ophthalmic laser 12 or the treatment device 10, which contain the adapted treatment coordinates. The eye can then be controlled using this data to remove the tissue 14.

[0047] Overall, the examples show how a procedure for monitoring an eye for treatment with an ophthalmic laser can be provided to a treatment device.

Claims

[1] Method for monitoring an eye (16) for treatment with an ophthalmic laser (12) of a treatment device (10), wherein the treatment device (10) has a recording device (24) with at least two cameras (26, 28), wherein a first camera (26) is coaxially and a second camera (28) is non-coaxially aligned to an eye contact area (30) of the treatment device (10), the method comprising the following steps: - Detection of the eye (16) at the eye contact area (30) using recording data of the eye (16) which are recorded by at least one of the two cameras (26, 28) of the recording device (24), wherein if the recording data from one of the two cameras (26, 28) is impaired, the detection of the eye (16) is continued by the other unimpaired of the two cameras (26, 28); - wherein a coordinate system of the first camera (26) is linked to a coordinate system of the second camera (28) by a predetermined transformation matrix, so that the coordinate systems of the at least two cameras (26, 28) are registered to each other; - where impairment of the recording data of a camera (26, 28) is determined by means of an image analysis algorithm. [2] Method according to claim 1, wherein an affine transformation is performed by the transformation matrix. [3] Method according to one of the preceding claims, wherein the first camera (26) is used as the main camera for capturing the recording data, and the second camera (28) is used as a backup camera only if the recording data of the first camera (26) is affected. [4] Method according to one of the preceding claims, wherein the treatment device (10) has a contact element with a suction device, wherein the recording data is captured by the unaffected camera upon contact with the contact element but without fixation by the suction device. [5] Method according to one of claims 1 to 3, wherein the treatment device (10) has a contact element with a suction device, wherein the recording data is captured by the unaffected camera upon contact with the contact element and with fixation by the suction device. [6] Method according to one of the preceding claims, wherein the recording data of the eye (16) are recorded by the recording device (24) with different illuminations and / or different wavelengths. [7] Method according to one of the preceding claims, wherein additionally planned treatment coordinates for the treatment of the eye (16) are provided from predetermined diagnostic data of the eye (16), wherein a treatment coordinate transformation matrix is ​​determined from recording data of the eye (16) taken by the unaffected of the two cameras (26, 28) between a coordinate system of the diagnostic data and a coordinate system of the unaffected camera (26, 28), wherein the treatment coordinates are adapted by the determined treatment coordinate transformation matrix. [8] Method according to any one of claims 1 to 6, wherein during treatment of the eye (16) with laser pulses at least one irradiated position of the eye (16) is recorded by the unaffected camera (26, 28), wherein the recording data of the unaffected camera (26, 28) are transformed by a treatment coordinate transformation matrix into a coordinate system of predetermined diagnostic data, so that the at least one irradiated position of the eye (16) is assigned to a treatment coordinate planned for this purpose. [9] Treatment device (10) comprising at least one ophthalmic laser (12) and a recording device (24), wherein the recording device (24) comprises at least two cameras (26, 28), wherein a first camera (26) is coaxially and a second camera (28) is non-coaxially aligned to an eye contact area (30) of the treatment device (10), wherein the recording device is configured to acquire recording data of the eye (16) by at least one of the two cameras (26, 28) and, in the event of an impairment of the recording data from one of the two cameras (26, 28), to continue the acquisition of the recording data of the eye (16) by the other unimpaired of the two cameras (26, 28), wherein a coordinate system of the first camera (26) is linked to a coordinate system of the second camera (28) by a predetermined transformation matrix, such that the coordinate systems of the at least two cameras (26, 28) are registered to each other,wherein the treatment device (10) has a control unit (18) which is configured to determine an impairment of the recording data of a camera (26, 28) by means of an image analysis algorithm.

Images