Ophthalmic surgical system with deformable-sheath optical probe and motorized actuator

Abstract

The aim of the invention is to provide improved techniques for positioning an optical probe having a deformable sheath and an optical fiber arranged therein in an examination region. This problem is solved by an ophthalmic surgical system (100) having a motorized actuator (121) for the optical probe (60).

Description

[0001] DESCRIPTION

[0002] OPHTHALMOSURGICAL SYSTEM WITH OPTICAL PROBE WITH DEFORMABLE SHELL AND MOTORIZED ACTUATOR

[0003] TECHNICAL FIELD

[0004] Various examples of the disclosure relate to an ophthalmic surgical system having an optical probe having a deformable sheath and having a motorized actuator configured to adjust a beam deflection of light guided through the optical probe.

[0005] BACKGROUND

[0006] Optical probes are known in which a curvature of an optical fiber can be adjusted in order to adjust a beam deflection of light coupled out of the optical fiber.

[0007] For example, WO 2010 / 104752 A2 discloses an optical probe in which a needle rotates within an outer shell while the outer shell remains stationary. This results in a beam deflection of light coupled out of an optical fiber arranged in the needle. Such optical probes with a stationary outer shell have the disadvantage that the achievable beam deflection is limited, for example, to a few degrees.

[0008] To achieve greater beam deflections, optical probes are also known that have a deformable sheath within which the optical fiber is arranged. See, for example, US 8,075,553B2 or US 10,052,232 B2 or US 10,420,460 B2. However, it has been observed that with such optical probes with a deformable sheath, the ability to specifically visualize or illuminate specific target areas with light works well, but still has potential for improvement.

[0009] ABSTRACT Therefore, there is a need for improved techniques to position an optical probe with a deformable sheath and an optical fiber disposed therein in an examination area.

[0010] This problem is solved by the features of the independent patent claims. The dependent patent claims define embodiments.

[0011] An ophthalmic surgical system comprises an optical probe. The optical probe has a proximal end and a distal end. The optical probe comprises at least one optical fiber. The at least one optical fiber extends from the proximal end to the distal end. The optical probe further comprises a deformable sheath. The deformable sheath surrounds the optical fiber. The optical probe also comprises an actuator mechanism. This is configured to effect an adjustable beam deflection of light coupled out of the optical fiber by means of an adjustable curvature of the at least one optical fiber and the deformable sheath. The ophthalmic surgical system also comprises a motorized actuator. The motorized actuator is configured to actuate the actuator mechanism. The ophthalmic surgical system further comprises at least one electronic circuit.The at least one electronic circuit is configured to determine control signals. The control signals are determined based on at least one predefined scan pattern. The at least one electronic circuit is also configured to output the control signals at least to the motorized actuator. This allows the beam deflection to be successively changed (i.e., the beam deflection is variable) such that the output light scans the area surrounding the optical probe at the distal end using the at least one predefined scan pattern.

[0012] For example, the actuator mechanism can be designed as a tendon-like tensile actuation. A tensile tendon can exert a tensile force on the sheath or directly on the optical fiber. If a tensile tendon is shortened, this causes a force on the deformable sheath in the region of the distal end of the optical fiber. The deformable sheath is curved due to this tensile force, and as a result, the optical fiber arranged in the deformable sheath is also curved. To support this curvature, it would be conceivable for the elastic sheath to have different deformabilities (i.e., elastic moduli) in the region of the distal end. In particular, it would be conceivable for a deformability gradient to exist in the circumferential direction. By varying the deformability along the circumference of the sheath in this way, it can be achieved that, upon tensile actuation, the curvature occurs in a direction that is predetermined by an increased deformability of the sheath. In this way, for example,Symmetrical pulling action can also produce a targeted curvature in one direction. For example, tendon-like pulling action could involve two antagonistic tensile tendons. This allows the curvature to be adjusted particularly precisely, compared to using just one tendon, for example.

[0013] In the context of a tendon-like tensile actuation, as explained above, the deformable sheath can have a deformability gradient in the circumferential direction in the region of the distal end of the optical probe. Such a deformability gradient can be achieved, for example, by varying the material from which the deformable sheath is made. Such a deformability gradient could also be achieved by varying the thickness of the deformable sheath in the region of the distal end of the optical probe and along the circumferential direction. Another possibility would be for the deformable sheath to be made of a rib-like structure and for the geometry of these ribs to be changed in order to adjust the deformability gradient.

[0014] However, the use of a tendon-like tensile actuation and / or a deformability gradient are only examples of possible implementations of the actuator mechanism. Other possibilities are also conceivable. For example, the actuator mechanism could comprise a shape-memory material on the deformable sheath. The shape-memory material can assume a specific curvature, for example, when the sheath is pushed out of a less elastic jacket. However, the shape-memory material could also be activated by heating, for example, via a current flow; this would enable electrical actuation. The use of a shape-memory material for the actuator mechanism enables a particularly compact design of the actuator mechanism. This allows the cross-section of the optical probe to be reduced in the region of the distal end.

[0015] The motorized actuator is controlled to operate the actuator mechanism in a motorized manner. Manual operation of the actuator mechanism is thus eliminated. For example, an electric motor could be provided to drive a winch to wind up or retract a tension cord. If a shape-memory material is used, the actuator mechanism could cause a current to flow through a heating wire to create a curvature. The specific implementation of the motorized actuator depends on the specific implementation of the actuator mechanism.

[0016] By controlling the motorized actuator by the at least one electronic circuit based on the at least one scanning pattern, a relatively large area of ​​the surroundings can be scanned successively. For example, light can be emitted over an extended area that is larger than the individual field of view that can be illuminated by light coupled from the optical fiber in a single position of the optical probe.

[0017] The deformable shell can be made of an elastic material. The deformable shell could also be made of a relatively stiff material and provide deformability due to its shape (shape-induced elasticity). For example, the deformable shell could have a rib-like structure. The deformable shell could be made of a polymer material.

[0018] The at least one electronic circuit can be implemented, for example, by a control unit. The control unit can comprise, for example, a processor and a memory. The processor can load and execute program code from the memory so that, based on the program code, control functionality can be provided for the motorized actuator and / or other active elements. Furthermore, the at least one electronic circuit can also provide control functionality for one or more components of an ophthalmic surgical system that performs measurements based on light passing through the optical fiber.

[0019] The at least one electronic circuit could contain various types of circuits. For example, an FPGA (Field-Programmable Gate Array) circuit could be implemented, which is permanently configurable. Alternatively or additionally, an ASIC (Application-Specific Integrated Circuit) circuit could be used, which is specifically designed for a specific application and can therefore be more efficient than general-purpose circuits. Alternatively or additionally, a CPU (Central Processing Unit) could be used. This can load and execute program code from memory.

[0020] Using the techniques described above, a high degree of automation in the operation of the optical probe can be achieved. Various scan patterns can be implemented. Different examinations can be performed precisely. Different examination areas can be examined.

[0021] The ophthalmic surgical system may further comprise a robotic pick-up device. This is configured to position the optical probe in the region of the proximal end. The robotic pick-up device thus engages the optical probe at the proximal end.

[0022] The robotic holding device can grasp and move the optical probe in the region of the proximal end. The robotic holding device is generally arranged outside of an examination region into which the optical probe is inserted. For example, the robotic holding device can enable positioning of the optical probe with three translational and three rotational degrees of freedom. For example, a Z-positioning of the distal end of the optical probe can be effected; this means that the optical probe can be moved translationally along its longitudinal axis into or out of the examination region. Furthermore, the optical probe can be tilted. The rotation point of the tilting is close to the proximal end of the optical probe; accordingly, a lateral positioning of the optical fiber at its distal end is effected. Rotation orTwisting the optical fiber around its longitudinal axis is conceivable; together with the curvature of the optical fiber, this can enable different polar angles of positioning.

[0023] For example, it is possible to insert the optical probe into an examination area using the robotic pick-up device, for example, through a narrow access. This narrow access can be defined as a so-called "remote center of motion" (ROOM), so that movements of the optical probe are always carried out in such a way that the optical probe passes through this fixed reference point.

[0024] The at least one electronic circuit can also be configured to determine control signals for the robotic pickup device based on the at least one predetermined scan pattern and to output them to the robotic pickup device.

[0025] For example, the robotic pickup device can be used to position the distal end of the optical probe at a starting point of at least one scan pattern. The at least one electronic circuit can be configured to determine the control signals for the robotic pickup device such that a corresponding starting point of each of the at least one scan pattern is set by a translational movement of the optical probe perpendicular to the longitudinal axis of the optical probe and / or a tilt of the optical probe relative to the longitudinal axis of the optical probe. The scan pattern can then be implemented—after the distal end is positioned at the starting point—by changing the curvature of the optical probe at the distal end, without the robotic pickup device participating in traversing the scan pattern; however, this is only one example:

[0026] Alternatively or additionally, it would be conceivable for the robotic recording device to be used to implement the at least one scan pattern. The at least one electronic circuit can therefore control the robotic recording device to successively change the beam deflection so that the surroundings at the distal end are scanned with the at least one scan pattern. This provides further degrees of freedom for implementing the at least one scan pattern. It is possible for the robotic recording device to be configured to, based on corresponding control signals (from the at least one electronic circuit), selectively move the optical probe translationally along its longitudinal axis, and / or translationally perpendicular to its longitudinal axis, and / or tilt it relative to its longitudinal axis, and / or rotate it about its longitudinal axis. This makes it possible to implement, for example, spiral scan patterns.In general terms, the robotic recording device enables more complex scanning patterns than are possible with the adjustable curvature alone.

[0027] For example, it would be conceivable for the at least one electronic circuit to be configured to determine the control signals for the robotic recording device such that the optical probe passes through a stationary reference point. This stationary reference point can, for example, form a narrow access point to an interior space to be measured. An example would be a trocar when examining the interior of the eye as an exemplary examination region. The at least one electronic circuit can, in particular, be configured to determine the control signals for the robotic recording device such that the optical probe passes through this stationary reference point, regardless of the successive change in the beam deflection based on the at least one scan pattern, and to scan the area surrounding the optical probe at its distal end.This means that at least one scan pattern is implemented, but the movement of the optical probe is adjusted such that it runs continuously through the fixed reference point as the RCOM. In this way, for example, scan patterns can be implemented in an interior space / in a cavity as examples of examination areas, whereby the cavity is only accessible through a narrow access (at which the reference point is arranged). For example, the optical probe can be moved translationally along its longitudinal axis, i.e., pushed into the cavity or pulled out of the cavity through the narrow access. Such a movement does not change the position of the optical probe with respect to the fixed reference point. Another movement that can be performed would be a rotation of the optical probe around a rotation axis that runs along the longitudinal axis of the optical probe.The optical probe can also be tilted if the tilt occurs around an axis that passes through the fixed reference point.

[0028] In particular, the robotic recording device can be used to implement multiple scanning patterns that scan different areas of the environment of the optical probe at the distal end.

[0029] Different variants are conceivable in connection with the at least one scan pattern. For example, a one-dimensional (1D) or a two-dimensional (2D) scan pattern can be used. The 1D scan pattern can, for example, be enabled solely by adjusting the curvature; whereas for the 2D scan pattern, tilting and / or rotation of the optical probe using the robotic pickup device is also used.

[0030] In general, a scan pattern can specify an azimuthal position or angle and a polar position or angle, as well as an orientation of the optical fiber at the distal end. These parameters define the beam deflection.

[0031] The scan pattern can be scanned either stepwise or continuously. When scanning the scan pattern stepwise, a pause is inserted between two steps so that the distal end of the optical probe no longer moves or no longer moves significantly. During this pause, for example, light can be transmitted or received through the optical fiber and / or a corresponding measurement point can be recorded. Typically, such a stepwise scanning of the scan pattern can enable greater accuracy in adjusting the beam deflection; at the same time, however, the time required to scan the surrounding area or scan the scan pattern can be increased.

[0032] Generally, the adjustment of the curvature of the optical fiber or the adjustment of the beam deflection is performed non-resonantly. Such non-resonant adjustment is relatively slow but highly accurate.

[0033] The at least one scan pattern can comprise multiple overlapping scan patterns. This means that a larger surrounding area can be scanned by dividing the surrounding area into sub-areas, each sub-area being assigned a corresponding scan pattern. By providing the overlap, it can be ensured that no gaps occur when scanning the surrounding area. Such a technique could also be referred to as "scan stitching."

[0034] When scanning the environment, it is helpful to have knowledge of the beam deflection along the scan trajectory. It would be possible for the at least one electronic circuit to be set up to determine an estimate of the beam deflection based on a model of the optical probe. Such a model of the optical probe can specify the beam deflection as a function of the actuation of the actuator mechanism and / or the positioning by the robotic recording device. The model can therefore be referred to as a transfer function, which, for example, directly maps the control signals for the actuator mechanism and / or the robotic recording device to a beam deflection. Such a model of the optical probe can, for example, be implemented or inferred using calculations based on the kinematics of the actuator mechanism and / or the robotic recording device and / or the optical probe.For example, the deformability of the optical probe's sheath can be considered. It can be considered how a force acting on the optical probe's sheath causes a curvature of the optical probe's sheath and thus a curvature of the at least one optical fiber.

[0035] Corresponding inference using the model can, for example, be carried out at runtime. However, it is also conceivable for the model's output values ​​to be pre-calculated. In this case, a lookup table could be used at runtime. Such a lookup table can, for example, store a connection between certain values ​​for the control signals and the resulting beam deflection. The model can be a heuristic model. The model can be derived from fundamental mechanical equations. However, the model could also be a machine-learned model, e.g., a deep artificial neural network. The model can contain linear and, optionally, non-linear components. The model can be initialized at a reference beam deflection or zero position. For example, at the zero position of the motorized actuator and / or the robotic pickup device, the beam deflection can be precisely known and used as a reference.Starting from the zero position of the motorized actuator and / or the robotic pick-up device, changes in the control signals can then be tracked to determine the resulting change in beam deflection.

[0036] For example, it would be conceivable for the at least one electronic circuit to be configured to determine the control signals for the motorized actuator and / or for the robotic pickup device based on the beam deflection estimate obtained from the model. The model of the optical probe can be used to determine the appropriate control signals based on a target specification for the beam deflection. The target specification for the beam deflection can be defined by the at least one scan trajectory. In other words, it would be conceivable for the model to be inverted and then, based on the inverted model for a desired beam deflection, the corresponding control signals for the motorized actuator and / or the robotic pickup device to be determined.

[0037] In some variants, it may be desirable to validate or adjust the beam deflection estimate using a positioning measurement. This is based on the realization that errors can accumulate in a purely model-based beam deflection estimate. For example, if the reference beam deflection is only known with high reliability in a zero position of the actuator mechanism and a change in the beam deflection is then determined by the model based on this reference beam deflection (as described above), errors can be integrated. In such a variant, it is helpful to use a positioning measurement. There are different variants for performing such a positioning measurement. Examples include image-based tracking of the optical probe. For example, the positioning (ieThe position and / or curvature of the distal end of the optical probe can be extracted using a suitable algorithm from corresponding images showing the movement of the optical probe. Other variants use a strain measurement to determine the curvature of the at least one optical fiber. Such a strain measurement could be performed, for example, using a fiber Bragg grating in the optical fiber or an electrical measurement using a strain sensor arranged on the optical probe in the region of the distal end.

[0038] In particular, aspects were described above in which a model of the optical probe is determined based on the kinematics of the deformable sheath. In some variants, it would be possible to assume that the shape and orientation of the deformable sheath directly determine the shape and orientation of the at least one optical fiber. In such a case, it may be unnecessary to model the kinematics of the at least one optical fiber separately. In other variants, however, it would also be conceivable to model the kinematics of the at least one optical fiber separately. This can be particularly desirable if the at least one optical fiber can move relative to the deformable sheath.

[0039] In some variants, it would be conceivable for more than a single optical fiber to be provided in the optical probe. Multiple optical fibers can extend parallel to one another within the deformable sheath of the optical probe. In such a scenario with multiple optical fibers, a relative movement of the ends of the optical fibers at the distal end of the optical probe can occur; such relative movement can lead to a change in the beam deflections of light guided in the multiple optical fibers relative to one another. It would be conceivable for the model of the optical probe used to estimate the beam deflection to model such relative movement of the multiple optical fibers to one another. This makes it possible to provide appropriate correction terms for certain applications that require light guided through the multiple optical fibers.These correction terms can compensate or at least reduce the influence of the relative movement of the multiple optical fibers to each other.

[0040] Alternatively or additionally, the model could also model dynamic effects of the movement of the at least one optical fiber. An optical fiber has a certain mass inertia. Particularly during rapid movement along a scan trajectory of the at least one scan pattern, this mass inertia can influence the beam deflection. Both linear and nonlinear dynamic effects can be taken into account. For example, it would be conceivable for the end of the at least one optical fiber to move relative to the cladding. Such a relative movement of the end of the at least one optical fiber relative to the cladding could be modeled. It can also be taken into account that, due to inertia, the end of the optical fiber is present with a certain latency in a movement of the cladding. By taking such dynamic effects into account, the beam deflection can be estimated more accurately.

[0041] In some variants, the model can be fixed. This means that the model parameter values ​​of the model are fixed and are fixed regardless of the respective instance of a measurement. In other variants, however, it would also be conceivable for the at least one electronic circuit to be configured to set one or more model parameter values ​​of the model as part of a calibration measurement. Such a calibration measurement could, for example, be carried out in the preparatory phase of a surgical procedure. This allows for better adaptation to the specific measurement environment. There are different ways to carry out such a calibration measurement. For example, a reference environment could be scanned using the at least one scan trajectory and the model parameter values ​​could then be set based on an available ground truth about the shape or pattern of the reference environment.

[0042] The disclosed ophthalmic surgical system can be used to implement various applications or measurement modalities. In particular, it is possible to perform multiple applications or measurement modalities in parallel using a single optical probe. For this purpose, it can be particularly useful if the optical probe comprises more than a single optical fiber. For example, multiple optical fibers can guide light for multiple optical applications or measurement modalities.

[0043] It would be conceivable that the at least one electronic circuit is configured to control an optical measuring device in order to carry out distance measurements along at least one of the at least one scanning pattern based on the light.

[0044] Such distance measurements can, for example, use a time-of-flight method and / or modulation of continuous, phase-coherent light sources. With a time-of-flight method, the time between the emission and detection of a pulse can be measured. For example, it would be possible to determine the topography of the surroundings based on such distance measurements. A map of the surroundings can be generated that includes the corresponding topographic information. For example, a volume model of the surroundings could be generated.

[0045] Alternatively or additionally, it would be possible to incorporate the result of such a distance measurement(s) into the control of the motorized actuator and / or the robotic pickup device. For example, collision avoidance could be implemented. Based on the distance measurements, one or more restricted areas could be defined, and the control of the motorized actuator and / or the robotic pickup device could be adjusted accordingly so that the distal end of the optical probe does not enter this restricted area.

[0046] In such a case, the distance measurements are not necessarily used as a stand-alone measurement modality, but as a technique to improve the positioning of the optical probe and thus enable another measurement modality, for example a tomography measurement, and / or another optical application, e.g. laser coagulation.

[0047] For example, it would be conceivable for the at least one electronic circuit to be configured to control a light source based on the distance measurements, so that the light source couples further light into the at least one optical fiber (the distance measurements could be implemented using light guided by a first optical fiber; and the further light can then be guided through a second optical fiber) with a light intensity, wherein the light intensity is determined as a function of the distance measurements. For example, the light source could be switched on and off depending on the distance value determined during the distance measurements. In this way, sensitive structures that are located particularly close to the distal end of the optical probe could be protected. For example, a photocoagulation laser could be controlled as a function of the distance measurements, e.g.on and off. By using the distance measurements to control the additional light source, the light exposure of structures in the vicinity of the optical probe can be precisely controlled and monitored. For example, by adjusting the light intensity, the light flux per area on the surface of an observed structure in the vicinity of the distal end of the optical probe could be kept constant, taking into account any divergence of the light after it has been coupled out of the at least one optical fiber. The electronic circuit can be set up to control an optical measuring device in order to carry out a tomographic measurement based on the light. A tomographic measurement is a special type of distance measurement. A tomographic measurement enables layer-by-layer imaging of a structure, for example tissue.This means that not only the distance to the surface of the respective structure, for example to the tissue, can be measured, as with a conventional distance measurement, but also details below the surface of the respective structure.

[0048] For example, in eye surgery, interventions are performed on the anterior chamber and / or the retina. Since the anatomical structures of the eye are often transparent or semi-transparent and usually very small, such interventions place high demands on visualization. To enable suitable imaging of anatomical structures in eye surgery, so-called optical coherence tomography (OCT) can be used. The at least one electronic circuit can be configured to control an optical measuring device in order to use the light guided by the at least one optical fiber to generate an OCT scan. Based on this, for example, a tomographic volume model of the surrounding area can be generated.

[0049] It is possible for the at least one electronic circuit to be configured to determine a map of the surroundings based on an estimate of the beam deflection obtained based on a model of the optical probe. Aspects related to such a model have already been described above and can also be used in connection with the variant described here. The map of the surroundings can be created based on one or more measurements, for example a distance measurement, such as a tomographic measurement. In this way, a "modeling" of the surroundings can take place. For example, a volume model of the surroundings of the distal end of the optical probe could be generated. By also taking the estimate of the beam deflection into account, certain structures in the map can be positioned particularly precisely.The beam deflection determines the location in the environment that is scanned with the corresponding measurement.

[0050] For example, the at least one electronic circuit can be configured to determine, based on the map of the environment, one or more restricted areas or restricted volumes (restricted regions) into which the optical probe should not penetrate. Due to the fact that the distal end of the probe is moved by a curvature of the sheath, the spatial area within which the distal end of the probe is moved is comparatively large—especially compared to scenarios in which an optical probe with a fixed, stationary sheath is used. Therefore, it can be particularly helpful to use the restricted regions to determine the control signals for the motorized actuator and / or the robotic recording device. In this way, structures in the examination area can be protected from damage caused by a collision with the optical probe.

[0051] Aspects in which a distance measurement, such as a tomography measurement, is performed were described above. For example, it would be conceivable for such distance measurements to be performed along a first scan pattern. Another measurement or an optical application, such as laser coagulation, can then be performed along a second scan pattern, which is scanned after the first scan pattern. Generally speaking, different scan patterns can be used for different measurement modalities and / or optical applications.

[0052] An example measurement modality would be contrast measurement. Contrast measurement is different from the distance measurement discussed above.

[0053] The at least one electronic circuit may, for example, be configured to control an optical measuring device to perform contrast measurements along at least one of the at least one scanning pattern based on the light.

[0054] The at least one electronic circuit can optionally be further configured to determine a tissue type as a function of position along the at least one scan pattern based on such contrast measurements. For example, the at least one electronic circuit could be configured to determine an indication of a tissue type for a map of the surrounding area based on the contrast measurements.

[0055] The at least one electronic circuit can be configured to control a light source to couple the light into the optical fiber in synchronization with the scanning of the surroundings with at least one of the at least one scan pattern. This means that the light source can be controlled depending on the progress along a scan trajectory of the at least one scan pattern: for example, the light source can be switched on and off, or its intensity can be changed.

[0056] Using such technology, different applications can be enabled.

[0057] For example, a laser coagulation light source could be controlled. If this is deliberately switched off, sensitive tissue can be protected. It is also conceivable that the surgical effect of laser coagulation could be specifically supported, e.g., by activating the light specifically at the tissue structure to be manipulated. Furthermore, tissue type information can be taken into account to control the laser coagulation light source. In some variants, it would even be conceivable for the scan pattern itself to be adjusted based on such tissue type information. For example, the scanned area could be aligned to the tissue to be manipulated. This could minimize scan time. Furthermore, sensitive tissue can be protected from laser coagulation and / or a surgical effect of laser coagulation can be supported.

[0058] In a further application, it is possible to control the light source such that a light pattern is projected onto the area surrounding the proximal end of the optical probe. Such a light pattern could, for example, be a checkerboard pattern. Such a light pattern could, for example, comprise parallel lines. A line grid could be projected. The at least one electronic circuit can be configured to control the light source based on a topographical indication (derived, for example, from a distance measurement, as described above) such that distortions of the light pattern due to the topography are reduced. Such a light pattern can be helpful for examining structures of the examination area in the area surrounding the optical probe.

[0059] Conversely, it would also be conceivable that the topography of the surroundings could be determined based on the appearance of the light pattern. This appearance can be captured by the optical probe. For example, a ground truth about the light pattern might be available, and based on the actual appearance of the light pattern and the ground truth, the topography could then be inferred, causing a corresponding distortion.

[0060] Different measurement modalities and / or optical applications have been disclosed above. Different optical fibers can be used for different measurement modalities and / or optical applications. For example, a first optical fiber could be used for distance measurement using the time-of-flight method. A second optical fiber could be used for tomography measurement. It would also be conceivable for a first optical fiber to be used to project a light pattern onto the surroundings, while an image of this light pattern is captured via a second optical fiber.

[0061] The at least one optical fiber can comprise multiple optical fibers. The multiple optical fibers can be connected to different light sources and / or detectors of the ophthalmic surgical system. In this way, different light, for example for different measurement modalities and / or optical applications, can be guided by the multiple optical fibers. Alternatively or additionally, it would also be conceivable for the at least one optical fiber to comprise at least one multi-core fiber. Such a multi-core fiber comprises multiple cores arranged side by side. In this way, light of different wavelengths can be guided in the different cores. In this way, multiple measurement modalities and / or applications can be enabled in parallel or sequentially.

[0062] It would also be conceivable for at least one optical fiber to be a multi-clad fiber. In this case, the optical fiber comprises several coaxially arranged claddings and can thus guide light of different wavelengths. This also allows for multiple measurement modalities and / or applications to be performed simultaneously or sequentially.

[0063] At least one of the at least one optical fiber can be a single-mode fiber. Such a single-mode fiber can have a particularly small cross-section. This also allows the cross-section of the optical probe to be reduced. However, it would also be conceivable for at least one of the at least one optical fiber to be a multi-mode fiber.

[0064] The ophthalmic surgical system can, for example, have multiple light sources configured to generate light of different wavelengths. For example, light could be generated in the infrared range and further light in the visible spectrum. The optical probe can have a coupler at the proximal end configured to couple the light of the different wavelengths into a single optical fiber, for example, into different cores of a multi-core fiber or into a multi-clad fiber.

[0065] It would be conceivable for the optical probe to have at least one lens associated with the at least one optical fiber at the distal end. This means that light coupled out of the optical fiber at the distal end or coupled into the optical fiber at the distal end is shaped by the lens. The lens can be, for example, a gradient index lens, a spherical lens, or a converging lens. This can increase coupling efficiency at the distal end. Furthermore, the divergence of the light coupled out of the optical fiber could be reduced.

[0066] The use of an optical probe with a deformable sheath for OCT scans is disclosed.

[0067] The features set forth above and features described below may be used not only in the corresponding explicitly set forth combinations, but also in further combinations or in isolation, without departing from the scope of the present invention.

[0068] SHORT DESCRIPTION OF THE CHARACTERS

[0069] FIG. 1 schematically illustrates an exemplary ophthalmic surgical system with an optical probe comprising an optical fiber.

[0070] FIG. 2 schematically illustrates a scan pattern that can be traversed by adjusting the beam deflection using the optical probe.

[0071] FIG. 3 schematically illustrates several overlapping scan patterns according to various examples.

[0072] FIG. 4 is a flowchart of an exemplary method.

[0073] FIG. 5 illustrates the performance of a medical measurement with an optical probe inside the eye according to various examples.

[0074] DETAILED DESCRIPTION

[0075] The above-described properties, features and advantages of this invention, as well as the manner in which they are achieved, will be more clearly and readily understood in connection with the following description of the embodiments taken in conjunction with the drawings.

[0076] The present invention is explained in more detail below using preferred embodiments with reference to the drawings. In the figures, identical reference numerals designate identical or similar elements. The figures are schematic representations of various embodiments of the invention. Elements shown in the figures are not necessarily drawn to scale. Rather, the various elements shown in the figures are depicted in such a way that their function and general purpose will be understood by those skilled in the art. Connections and couplings between functional units and elements shown in the figures can also be implemented as an indirect connection or coupling. A connection or coupling can be implemented wired or wirelessly. Functional units can be implemented as hardware, software, or a combination of hardware and software.Techniques related to an optical probe are described below. The optical probe has one or more optical fibers. These can be multi-clad fibers, for example. Multi-core fibers can be used. One or more single-mode fibers could be used. Combinations of different fiber types are conceivable.

[0077] A distal end of the optical probe can be scanned. The beam deflection of light coupled out of the at least one optical fiber can thus be varied based on at least one scan pattern.

[0078] The optical probe is used in an ophthalmic surgical system. Various measurement modalities and / or applications can be enabled. Some measurement modalities and applications are listed below in Table 1.

[0079] TABLE 1: Applications and measurement modalities enabled by the described optical probes. The various variants can be combined.

[0080] In particular, an OCT measurement is possible (see Table 1, Example 2). OCT is an imaging technique that provides high-resolution, cross-sectional images of biological tissues. OCT is particularly widely used in ophthalmic surgery. In an OCT measurement, the interference between an object beam and a reference beam is determined. Primary light from the object beam is directed to the area to be measured; the light from the object beam then interacts with the surrounding area and is collected as secondary light. The phase shift is then determined.

[0081] There are different types of OCT, such as time-domain OCT and Fourier-domain OCT. The techniques described here can be used for all different types of OCT.

[0082] Techniques for capturing measurement points from an OCT measurement for A-scans and B-scans are described. An A-scan (amplitude scan) is a one-dimensional depth profile that shows the intensity of reflected light from different depths within a tissue or material. A B-scan (brightness scan) is a two-dimensional cross-sectional image created by stacking multiple A-scans side by side.

[0083] In the following, particular aspects relating to an optical probe for OCT measurements are described. An optical probe with a sheath and an optical fiber arranged in the sheath is disclosed, for example, in US 10,420,460 B2. The optical probe can be implemented based on the disclosure therein. The primary light of the object beam of the OCT measurement is guided via the optical fiber of the optical probe to an examination region arranged in the distal vicinity of the optical fiber. After interaction with the surroundings, the light is detected, e.g. again via the optical fiber (wherein the light is then coupled out at the proximal end of the optical fiber) or via a separate detection beam path (e.g. through the lens of the eye). Detection via the optical fiber can often enable a particularly high signal-to-noise ratio.

[0084] FIG. 1 schematically illustrates an ophthalmic surgical system 100 according to various examples. The ophthalmic surgical system 100 is configured to implement one or more optical applications or measurement modalities, for example, as listed in TABLE 1.

[0085] For this purpose, an optical device 123 is provided. This can comprise one or more light sources and / or one or more light detectors. The optical device 123 can, for example, comprise a wavefront manipulator, which can vary a phase position of the light field depending on the position in the light field. The optical device 123 can, for example, comprise one or more lasers or one or more light-emitting diodes. The optical device 123 could, for example, comprise a light source array. The optical device 123 could, for example, comprise a photodiode or a photodiode array. The optical device 123 could, for example, comprise a CCD sensor or a CMOS sensor. The optical device 123 can, for example, have optical measurement hardware, e.g., a light source for coherent light, a lens, an interferometer, a beam splitter, etc. The optical device 123 also comprises an electronic circuit for controlling the acquisition of measurement points.Optionally, the electronic circuit can also perform reconstruction to obtain A-scans or B-scans from the measurement points. Alternatively, such reconstruction can be performed by another electronic circuit.

[0086] Light 71 generated by the optical device 123 can be guided to the examination area 50 (here, a cavity) via an optical probe 60. For this purpose, the optical probe is arranged in a narrow access 52. The optical probe 60 has an optical fiber 132 that extends from a proximal end 61 of the optical probe 60 to a distal end 62 of the optical probe 60.

[0087] While in the example of FIG. 1 only one optical fiber 132 is present, the optical probe 60 may generally comprise more than a single optical fiber, for example, to enable different measurement modalities and / or optical applications.

[0088] For example, single-core or multi-core fibers can be used. Multi-cladding fibers could be used. Single-mode or multi-mode fibers can be used.

[0089] The optical probe 60 is configured to enable beam deflection of the light passing through the optical fiber by means of an adjustable curvature 91 of the optical fiber 132 in the region of the distal end 62. Different curvatures 91 correspond to different orientations of the fiber end of the optical fiber 132 and thus to different radiation angles for the light 71 coupled out at the distal end 62. As a result, depending on the orientation, different areas of the surrounding area 51 are illuminated. It is also shown that secondary light 72 from different areas of the surrounding area 51 can be coupled into the optical fiber 132 or into another optical fiber.

[0090] Also shown in the example of FIG. 1 is a lens 139, which is arranged at the distal end 62 of the optical probe 60 and is configured to shape light coupled out of the optical fiber 132, for example, to reduce divergence. Such a lens 139 is optional and not required in all variants.

[0091] The curvature 91 is adjusted by means of an actuator mechanism 90 of the optical probe 60. The curvature 91 is effected upon actuation of the actuator mechanism 90. In the example shown in FIG. 1, this is achieved by circumferentially variable deformability of the sheath 131; this means that the deformable sheath 131 has regions of different deformability at the distal end 62, which are spaced apart from one another in the circumferential direction. The actuator mechanism 90 then comprises a tendon-like tensile actuation, e.g., in the form of two antagonistically acting tensile tendons. If a tensile force is applied by the actuator mechanism 90 in the region of the distal end 62 toward the proximal end 61, the deformability gradient creates the curvature 91. However, other types of actuator mechanisms would also be conceivable, e.g., electrical, magnetic, thermal, or using shape memory material.

[0092] The deformable shell 131 can, for example, be made of an elastic material. Alternatively or additionally, the provision of shape-induced deformability would also be conceivable. For example, a relatively inelastic plastic with a rib-like structure can be used, thus providing shape-induced deformability.

[0093] To actuate the actuator mechanism 90, the ophthalmic surgical system 100 includes a motorized actuator 121. The motorized actuator 121 receives control signals from a control unit 125 and actuates the actuator mechanism 90 based on the control signals. In an implementation using a tendon-like pulling actuation, this means, for example, that the one or more tendons are pulled or not pulled. If one or more tendons are pulled, the deformability gradient in the region of the distal end 62 results in a different contraction effect in the different regions of the deformable sheath 131, resulting in the curvature 91. This achieves the beam deflection of the light 71. The curvature 91 is set, for example, to be non-resonant or quasi-static. The tensile force exerted on a tendon is proportional to the strength of the curvature 91.This means that different curvatures 91 can be set in stages.

[0094] The ophthalmic surgical system 100 further includes a robotic pickup device 122. The robotic pickup device 122 grasps the optical probe 60 in the region of the proximal end 61 or outside the examination area 50. The robotic pickup device 122 is configured to position the optical probe 60 in the region of the proximal end 61; positioning in the region of the proximal end 61 also achieves positioning in the region of the distal end 62.

[0095] In different implementations, the robotic pick-up device 122 may include a different number of degrees of freedom for this positioning. For example, it would be possible for the robotic pick-up device 122 to be configured to rotate the optical fiber 132 about its longitudinal axis based on control signals received from the controller 125; the corresponding third rotational movement 87 is shown in FIG. 1. The rotation about the longitudinal axis can enable complex scanning patterns by synchronizing with the adjustment of the curvature 91 (as described in detail later).Alternatively or in addition to such a third rotational movement 87 about the longitudinal axis of the optical fiber 132, it would be possible for the robotic pickup device 122 to be configured to move the optical fiber 132 translationally along its longitudinal axis (longitudinal movement 83; useful, for example, for introducing the optical probe 60 into the examination region 50) and / or perpendicular to its longitudinal axis (first translational movement 81 and second translational movement 82). A first rotational movement 85 and a second rotational movement 86 about axes perpendicular to the longitudinal axis of the optical fiber 132 would also be conceivable; this corresponds to a tilting of the optical fiber 132. In particular, an implementation of the robotic pickup device 122 that allows six degrees of freedom (three translational degrees of freedom and three rotational degrees of freedom, as shown in FIG. 1) would be possible.

[0096] By positioning the optical probe 60 in this way, the optical probe 60 can always pass through a fixed reference point 160 (remote center of motion) for different positionings. Tilting (first and second rotational movements 85, 86) is particularly helpful for this purpose. This can be particularly useful when the optical probe 60 is used in a cavity (as an example of an examination area) with a narrow access 52 (for example, a trocar in eye surgery), in which case the reference point 160 is selected to coincide with the narrow access to the cavity. In this way, even otherwise difficult-to-access interior areas can be examined.

[0097] The motorized actuation of the actuator mechanism by means of the motorized actuator 121 and / or the positioning by means of the robotic recording device can also be used, in particular, to implement one or more scan patterns—e.g., for a B-scan of the OCT measurement or to create a map with a topography of the surroundings. This will be explained next. The control unit 125 can be configured to provide control signals to the motorized actuator 121 and / or the robotic recording device 122 in order to implement one or more scan patterns for changing the beam deflection. This means that the control signals for the motorized actuator 121 and / or the robotic recording device 122 can be determined based on a scan pattern. Large environmental areas can be scanned automatically using the scan pattern.For example, data can be loaded that specifies the scan pattern; then this data can be translated into concrete control signals to implement the scan pattern.

[0098] For this purpose, for example, a model of the optical probe 60 and in particular of the actuator mechanism 90 can be taken into account; this model specifies how settings of the motorized actuator 121 and / or the robotic holding device 122 translate into an alignment and / or orientation and / or rotation of the optical probe 60 at the distal end 62, i.e., for example, which curvature 91 is caused or how actuation of the actuator mechanism 62 causes a change in the curvature 91. The model therefore makes it possible to determine an estimate of the beam deflection. This is helpful because the beam deflection is typically not directly measurable. Within the framework of such a model, for example, dynamic effects can be taken into account which indicate how the optical fiber 132 behaves within the sheath 131 during rapid movement of the optical probe 60.Alternatively or additionally, such a model could also take into account relative movements of the distal ends of several optical fibers arranged within the sheath 131.

[0099] FIG. 2 illustrates aspects related to an exemplary scan pattern 210, here a spiral scan pattern 210. The spiral scan pattern 210 in the example of FIG. 2 is determined as follows. The starting point 211 (here the center) is reached by a translational movement at the proximal end and, if necessary, a tilt (compare FIG. 1: first and second translational movements 81, 82 perpendicular to the longitudinal axis of the optical fiber 132; as well as first and second rotational movements 85, 86 about these axes, whereby the tilt is achieved).

[0100] When the optical fiber 132 is positioned at the starting point 211, the spiral scan pattern 210 can be gradually scanned by a third rotational movement 87 around the longitudinal axis of the optical fiber 132 and the curvature 91 at the distal end 62 of the optical fiber 132. The curvature 91 defines the azimuthal angle 225, and the third rotational movement 87 around the longitudinal axis of the optical fiber 132 defines the polar angle 226. Thus, the position and orientation of the optical fiber 132 at the distal end 62 are adjusted by the scan pattern 210. The beam deflection can thus be changed. In some examples, it would be conceivable for a tilt of the optical fiber 132 to be adjusted in synchronization with the adjustment of the curvature 91. The azimuthal angle 225 can then be adjusted by the curvature 91 together with the tilt; this enables larger scanning ranges.

[0101] The scan pattern 210 can, for example, be traversed step by step to capture a corresponding measurement point for a distance measurement, a tomography measurement, or a reflectance measurement, etc. (some measurement points 212 are shown in FIG. 2). Such a step-by-step traversal of the scan pattern 210 must be distinguished from a continuous movement, particularly in resonant scanning. It would also be conceivable in the scenarios described here that, for example, the curvature of the optical fiber is continuously changed; then—due to the finite sampling time interval for a measurement point—there is a certain inaccuracy in the lateral spatial resolution; however, this may be acceptable in view of the overall reduced measurement time.

[0102] FIG. 3 illustrates a scenario in which several overlapping scan patterns 210-1, 210-2, 210-3 (here also exemplary spiral scan patterns, although other shapes are also conceivable) are shown, whose starting points 211-1, 211-2, 211-3 are offset from one another. This allows larger areas of the surroundings to be scanned. By arranging the scan patterns in an overlapping manner, a larger portion of the examination area can be scanned.

[0103] Particularly in the case of such a large-area scanning of the examination region, as shown in FIG. 3, it is helpful to consider a fixed or stationary reference point 160; that is, for all scan patterns 210-1, 210-2, 210-3, the optical fiber 132 always runs through the stationary reference point 160.

[0104] FIG. 4 is a flowchart of an exemplary method. The method of FIG. 6 relates to the operation of an ophthalmic surgical system, e.g., for an OCT measurement. The method of FIG. 6 can be executed by at least one electronic circuit of the ophthalmic surgical system. For example, the method of FIG. 6 could be executed by a control unit and an optical device. For example, the method of FIG. 6 could be executed by one or more processors based on program code loaded from one or more memories. For example, the method of FIG. 4 could be executed by the control unit 125 and the optical device 123 of the ophthalmic surgical system 100 according to FIG. 1. The method of FIG. 4 generally relates to aspects related to scanning the environment using an optical probe. In particular, the optical probe 60 can be used according to the example of FIG. 1.A motorized actuator and / or a robotic pickup device may be used to scan the optical probe, as described above, for example, in connection with FIG. 1 (robotic pickup device 122 and motorized actuator 121).

[0105] In box 904, a model of the optical probe or beam deflection can optionally be calibrated as a function of control signals for a motorized actuator and / or a robotic probe pick-up device. This occurs in a preparatory phase. For this purpose, the optical probe could be used to measure a reference pattern. Different positions within the reference pattern can then be assigned to different beam deflections, thus establishing a link to the corresponding control signals. The position along the reference pattern can be available based on ground truth associated with the reference pattern. Model parameter values ​​can then be set accordingly.

[0106] For example, in box 904, a lookup table could be generated that specifies the dependence of the beam deflection on various control signals for the motorized actuator and / or the robotic pickup device. This enables a particularly rapid and, in particular, real-time estimation of the beam deflection during a measurement, i.e., during box 915 (explained in detail below).

[0107] Optionally, calibration of the optical path length of the optical probe is also required, as the optical fiber length can vary, affecting, for example, the distance measurement. This can be done using a test object that can simultaneously calibrate the A-scan (depth) and deformation (B-scan).

[0108] For example, during the calibration of Box 904, a checkerboard-like 3D test object with various glass depths and notches can be used. This allows distance and lateral positioning to be calibrated.

[0109] In box 905, the optical probe is arranged in an examination area, for example in an interior space or a cavity, such as the interior of the eye. For example, the optical probe in box 905 can be introduced into the examination area via an access point; for example, in connection with an eye surgery, a trocar could be used to provide access to the interior of the eye. This access can define a stationary reference point (cf. FIG. 1: stationary reference point 160; and narrow access 52) for the movement of the optical probe; this means that regardless of the specific positioning of the optical probe, this means, for example, regardless of the curvature in the region of the distal end or the tilting or translational movement in the region of the proximal end, the optical probe can always pass through the stationary reference point.In box 905, a robotic pickup device is controlled to effect corresponding translational and / or rotational movements of the optical probe. The robotic pickup device (see FIG. 1: robotic pickup device 122) grasps the optical probe at or near its proximal end, i.e., particularly outside the area of ​​the optical probe that is introduced into the examination region.

[0110] In box 906, a current scan pattern is selected. An exemplary scan pattern 210 was discussed in connection with FIG. 2. For example, in connection with FIG. 3, aspects were described of how multiple overlapping scan patterns 210-1, 210-2, 210-3 can be used to control the various components of the ophthalmic surgical system. Accordingly, in box 906, the control of the components can be prepared by selecting a current scan pattern.

[0111] Then, in box 910, the robotic pickup device is controlled and, optionally, the optical probe is actuated to adjust a curvature, so that a starting point of the scan pattern selected in the current iteration 931 of box 906 is approached. This means that the optical probe, or in particular the optical fiber, can be tilted in the region of the proximal end relative to its longitudinal axis. A suitable curvature of the optical fiber can also be adjusted by actuating the optical probe.

[0112] The scan pattern is associated with a sequence of target values ​​for the beam deflection. Optionally, the scan pattern can also be associated with a sequence of target positions of the optical fiber in the region of the distal end. Accordingly, in box 915, the optical probe is actuated to adjust the curvature of the optical fiber based on a corresponding target value for the beam deflection; and the robotic pick-up device is controlled to position the optical fiber in the region of the proximal end based on the target value for the beam deflection. For this purpose, a model of the probe, which was optionally calibrated in box 904, can be considered.

[0113] In detail, in box 915, the actuation of the optical probe and the control of the robotic pickup device for traversing the scan pattern, i.e., for implementing several target values ​​for the beam deflection, can be performed in an uncontrolled or controlled manner. For example, it would be possible to consider a model of the actuator mechanism for adjusting the curvature to determine an estimate of the beam deflection. It would be conceivable to perform a positioning measurement for the distal end of the optical fiber in a closed control loop. This estimate of the beam deflection can then be adjusted based on a corresponding positioning measurement. Various options for a corresponding positioning measurement are conceivable.For example, image-based tracking of the elastic sheath at the distal end of the optical probe could be performed (during ophthalmic surgery, through the lens of the eye, whose optical effect can be computationally compensated). Strain measurement could also be performed to determine the curvature. For example, a fiber Bragg grating embedded in the optical fiber could be used, tuned to a different wavelength range than the wavelength of the light of the object beam. Alternatively or additionally, an electrical strain sensor could also be mounted in the region of the distal end.

[0114] The scan pattern is traversed, typically in a stepwise fashion (stepped mode); simultaneously, measurement points for a specific measurement are captured in box 920. For example, secondary light from the object beam is detected during an OCT measurement: A phase shift between the reference beam and the secondary light from the object beam is then determined.

[0115] The secondary light detected in box 920 (after interaction with the environment of the optical probe) can generally be detected via the optical probe or via another detection path. This means that it is possible for the secondary light to be coupled back into the optical fiber of the optical probe and then output at its proximal end. However, it is also conceivable that the light no longer travels back to the detector via the optical fiber, but via another path (e.g., via the lens of the eye during ophthalmic surgery).

[0116] Alternatively or in addition to box 920, box 921 can also be executed. In box 921, a light source is switched on or off in synchronization with the scanning trajectory defined by the scanning pattern. The light intensity could also be varied. For example, laser manipulation could be performed. For example, laser coagulation could be performed. Instead of laser manipulation, a light pattern could be projected, for example.

[0117] Various variants for Box 920 and Box 921 were discussed above in connection with Table 1.

[0118] Box 915 also ensures that the optical probe always passes through the fixed reference point while traversing the scan pattern.

[0119] In box 930, a check is made to determine whether another scan pattern should be implemented; if so, a further iteration 931 is executed, i.e., in a further iteration 931 of box 916, another current scan pattern is determined or selected, and then the following boxes are executed.

[0120] For example, it would be conceivable for a predefined scan pattern to be selected in a first iteration 931 of box 906. One or more further scan patterns in one or more subsequent iterations 931 of box 906 can then be determined based on the measurement points from box 920. For example, it would be conceivable for a topography of the surroundings of the optical probe at its distal end to be performed based on a distance measurement in a first iteration 931 of box 920. Based on such a distance measurement, raised areas (cf. bulge 59 in FIG. 1) can then be determined where there is a risk of collision with the optical probe. Based on such a map of the surroundings of the optical probe, it is possible to determine restricted regions into which the optical probe should not penetrate. This can be taken into account when determining a scan pattern in a subsequent iteration 931 of box 906.However, in such a determination of the scan pattern in a subsequent iteration 931 of box 906, a tissue type could also be taken into account, for example, which was determined by means of a contrast measurement in box 920 of a previous iteration 931. Accordingly, it would be conceivable for the measurement point from box 920 to be processed in box 932, for example, to determine the distance value, determine the tissue type, map an environment of the optical probe, and / or determine restricted regions.

[0121] Once all measurement points for all one or more scan patterns have been acquired, the probe is extracted from the examination area in box 935; for this purpose, the robotic recording device is again controlled accordingly.

[0122] In box 940, optional post-processing of the measurement points acquired in box 920 takes place. For example, a map of the surrounding area can be determined. For example, a topography of the surrounding area could be determined. A reflectance map could be determined. It would also be possible to reconstruct an A-scan or a B-scan of an OCT measurement.

[0123] The post-processing in box 940 can, in particular, take into account the beam deflection for each of the measurement points from box 920. This means that the orientation and position (positioning) of the distal end of the optical fiber can be taken into account. For this purpose, an appropriate model can be used to determine the beam deflection estimate, which may have been calibrated. The actual spatial position of the measurement point can be determined. In particular, for example, the azimuthal position (cf. FIG. 2: azimuthal angle 225) and the polar position (cf. FIG. 2: polar angle 226) and an orientation of the distal end of the optical fiber can be taken into account. A z-offset can also be taken into account: the curvature causes the distal end of the optical fiber to move on a curved surface; the z-position of this curved surface can be compensated in the reconstruction.

[0124] Since the beam deflection is only adjusted indirectly (via the actuator mechanism and the robotic pick-up device, both controlled at the distal end), the beam deflection can be estimated based on the control signals. A suitable model can be used to translate the control signals into beam deflection (as already described above in connection with box 915 for the control).

[0125] The method from FIG. 4 can be used for various examination objects. In particular, the method from FIG. 4 can be carried out in connection with an OCT measurement during an eye surgery. A corresponding example is shown in FIG. 5. There, the eye 1900 with the retina 1901 is shown. Also shown are the cornea 1902, the iris 1903, the lens 1904, retinal blood vessels 1905 and the macula 1906. It is also shown how the optical fiber 132 (together with the optical probe 60) can be introduced into the interior of the eye via a corresponding access point (which coincides with a fixed reference point 160, as discussed above) in order to thus make otherwise difficult-to-access examination areas 1980 accessible for the OCT measurement due to the curvature. In FIG.Figure 5 also illustrates how two overlapping scan patterns 210-1, 210-2 can be used to implement a B-scan of the OCT measurement. Accordingly, it would also be possible to generate volumetric scans.

[0126] In summary, the above techniques for controlling an optical probe have been described. The optical probe has at least one optical fiber, which can be bent in the region of its distal end using a suitable actuator mechanism of the optical probe.

[0127] For example, a scan pattern can be implemented by appropriately positioning the optical fiber and adjusting its curvature. The proximal end of the optical fiber can be positioned, for example, rotated or tilted (robotic pickup devices as described above can be used for this purpose); this causes the distal end of the optical fiber to perform a corresponding movement. In particular, the following five degrees of freedom can be used to move to the starting point of a scan pattern and then to scan the scan pattern: curvature of the tip of the optical fiber; rotation of the optical fiber about its longitudinal axis; translational forward or backward movement along the longitudinal axis of the optical fiber; and tilting of the optical fiber by rotation about an axis perpendicular to the optical fiber.This can be motorized and performed at high speed; for example, the curvature could oscillate between two curvature values.

[0128] In summary, the following aspects were described in particular:

[0129] An ophthalmic surgical system for examining an examination area is disclosed. The ophthalmic surgical system comprises an optical probe having a proximal end and a distal end and comprising at least one optical fiber extending from the proximal end to the distal end, a deformable sheath surrounding the at least one optical fiber, and an actuator mechanism configured to effect an adjustable beam deflection of light coupled out of the optical fiber by means of an adjustable curvature of the at least one optical fiber and the deformable sheath. The ophthalmic surgical system also comprises a motorized actuator configured to actuate the actuator mechanism.The ophthalmic surgical system also comprises at least one electronic circuit configured to determine control signals for the motorized actuator based on at least one predetermined scan pattern and to output them to the motorized actuator, whereby the beam deflection can be successively changed such that the output light scans an area surrounding the optical probe at the distal end with the at least one scan pattern.

[0130] Such an ophthalmic surgical system offers the advantage of allowing a relatively large examination area to be measured by scanning the surrounding area; at the same time, complicated manual handling of the optical probe is not required. Automatic measurement is possible.

[0131] The ophthalmic surgical system may further comprise: a robotic pickup device configured to position the optical probe, wherein the at least one electronic circuit is configured to further determine and output control signals for the robotic pickup device based on the at least one predetermined scan pattern to the robotic pickup device.

[0132] The robotic imaging system enables even complex scanning patterns with many degrees of freedom, allowing for a comprehensive examination of the examination area.

[0133] The at least one electronic circuit can be configured to determine the control signals for the robotic recording device such that the optical fiber passes through a fixed reference point, regardless of the successive change in the beam deflection for scanning the at least one scan pattern. In this way, cavities or hollow spaces with a narrow access can also be examined internally by placing the fixed reference point on the narrow access.

[0134] The at least one electronic circuit is configured, for example, to determine the control signals for the robotic recording device such that a corresponding starting point of each of the at least one scanning pattern is set by at least one of a translational movement of the optical probe perpendicular to the longitudinal axis of the optical probe or a tilting of the optical probe relative to the longitudinal axis of the optical probe.

[0135] This makes it possible to arrange scan patterns at different positions within the examination area. For example, stitching techniques can be used to enable a larger field of view through combined scan patterns.

[0136] It is possible that the robotic pickup device is configured to move the optical probe translationally along its longitudinal axis based on the control signals.

[0137] In this way, the optical probe can be positioned particularly precisely.

[0138] It is possible that the robotic pickup device is configured to move the optical probe translationally perpendicular to its longitudinal axis based on the control signals.

[0139] In this way, the optical probe can be positioned particularly precisely.

[0140] It is possible that the robotic pickup device is configured to tilt the optical probe relative to its longitudinal axis based on the control signals.

[0141] In this way, the optical probe can be positioned particularly precisely.

[0142] It is possible that the robotic pickup device is configured to rotate the optical probe around its longitudinal axis based on the control signals.

[0143] In this way, the optical probe can be positioned particularly precisely.

[0144] For example, the at least one scan pattern can specify an azimuthal position of the optical fiber at the distal end. This allows scan patterns with a particularly high number of degrees of freedom to be defined.

[0145] For example, the at least one scan pattern can specify a polar position of the optical fiber at the distal end. This allows scan patterns with a particularly high number of degrees of freedom to be defined. For example, the at least one scan pattern can specify an orientation of the optical fiber at the distal end. This allows scan patterns with a particularly high number of degrees of freedom to be defined.

[0146] The scan pattern can be traversed step by step. By traversing the measurement positions step by step, a stable signal can be acquired and typically a particularly high signal-to-noise ratio can be achieved.

[0147] The scan pattern can be scanned continuously. This reduces the time required to scan the pattern and enables particularly rapid data acquisition.

[0148] The at least one scan pattern can comprise multiple overlapping scan patterns. This allows the field of view of the entire measurement to be enlarged, meaning a larger environmental area can be measured.

[0149] The at least one electronic circuit may be configured to determine an estimate of the beam deflection based on a model of the optical probe.

[0150] By performing a model-based estimation of the beam deflection, the lateral position of a measurement point can be determined with exceptional accuracy. This increases the quality of the measurement.

[0151] For example, the at least one electronic circuit may be configured to determine the control signals for the motorized actuator and / or control signals for a robotic pickup device configured to position the optical probe based on the beam deflection estimate.

[0152] This allows feedback to be sent to the control system. This allows specific measurement points to be captured and the measurement to be performed with particularly high accuracy.

[0153] It would be possible for the at least one electronic circuit to be further configured to adjust the beam deflection estimate based on a positioning measurement.

[0154] Active control can therefore be carried out in order to carry out the measurement with particularly high accuracy.

[0155] It would be conceivable for the positioning measurement to include image-based tracking of the optical probe. Such image-based tracking can be performed relatively easily using a camera. It would be conceivable for the positioning measurement to include a strain measurement to determine the curvature. In this way, tracking can be performed even if the distal end of the optical probe is not visible from the outside.

[0156] It would be conceivable that the strain measurement is carried out optically by means of a fiber Bragg grating in the optical fiber or electrically by means of a strain sensor arranged on the optical probe in the region of the distal end.

[0157] In this way, the sensor for strain measurement can be integrated into the optical fiber itself, which is particularly space-saving.

[0158] It would be possible for the ophthalmic surgical system to include multiple optical fibers.

[0159] In this way, several measurement signals can be recorded simultaneously, which can increase the accuracy of the measurement.

[0160] For example, the model can model a relative movement of the multiple optical fibers to each other.

[0161] When comparing measurement signals acquired via multiple optical fibers, relative motion can have a negative impact on such a comparison. Such a negative impact can be compensated for if the relative motion is predicted by the model.

[0162] It would be conceivable that the model models dynamic effects of a movement of at least one optical fiber.

[0163] Especially during fast scanning processes, a more accurate prediction can be achieved using the model.

[0164] It is possible that the at least one electronic circuit is configured to set one or more model parameter values ​​of the model as part of a calibration measurement.

[0165] This allows the model to be calibrated to the specific optical probe. This provides improved accuracy, particularly compared to reference techniques in which a model is calibrated for a large number of identical optical probes.

[0166] The at least one electronic circuit is configured, for example, to perform the calibration measurement in a preparatory phase of a surgical procedure. This allows the calibration to be repeated from surgical procedure to surgical procedure. This allows not only calibration for a specific optical probe, but even calibration for a specific surgical procedure. This further improves accuracy.

[0167] It is possible that the at least one electronic circuit is configured to control an optical measuring device in order to perform distance measurements along at least one of the at least one scanning pattern based on the light.

[0168] Distance measurements can add another dimension to data collection, enabling improved diagnostics in the medical field. Surgical procedures can be controlled more precisely.

[0169] The distance measurements could use a time-of-flight method. Such a distance measurement can be implemented with relatively simple electronics. Furthermore, temporal resolution can be easily provided.

[0170] The distance measurements could use modulation of continuous, phase-coherent light waves. Such techniques often offer particularly high accuracy.

[0171] The at least one electronic circuit is configured, for example, to control a light source based on the distance measurements, so that the light source couples further light into the at least one optical fiber with a light intensity determined as a function of the distance measurements.

[0172] In this way, illumination can be tailored to in-situ distance measurements. The light intensity can be adjusted, for example, depending on the distance to an object. Tissue injury is thus avoided and / or the light dose per area can be precisely adjusted, for example, by taking into account a divergence in the beam path.

[0173] The distance measurements may include tomographic measurements such as a coherence tomography scan.

[0174] Tomographic measurements can enable certain types of diagnosis.

[0175] The at least one electronic circuit is configured, for example, to determine a topographical information in a map of the surrounding area based on the distance measurements. This allows not only the lateral position of specific features in the surrounding area or the examination area to be mapped; distance information can also be stored in the map. This increases the information value of a corresponding map.

[0176] If the at least one electronic circuit is configured to determine an estimate of the beam deflection based on a model of the optical probe, it would be possible for the at least one electronic circuit to be configured to determine a map of the environment based on the estimate of the beam deflection.

[0177] The lateral position of specific objects in the examination area can be determined more accurately by estimating the beam deflection and mapped accordingly. The map becomes more accurate.

[0178] The at least one electronic circuit is configured, for example, to determine, based on the map of the environment, one or more restricted regions into which the optical probe should not penetrate.

[0179] In this way, for example, sensitive objects, such as certain vulnerable tissue types, can be protected.

[0180] The at least one electronic circuit is further configured, for example, to determine the control signals for the motorized actuator and optionally control signals for a robotic pickup device of the optical probe based on the one or more blocking regions.

[0181] This allows the restricted areas to be protected automatically, preventing user error.

[0182] It is possible that the at least one electronic circuit is configured to control an optical measuring device to perform contrast measurements along at least one of the at least one scanning pattern based on the light.

[0183] Measurements contain a certain amount of information that can be beneficial for diagnosis.

[0184] The at least one electronic circuit may further be configured to generate a tissue type indication for the map of the surrounding area based on the contrast measurements.

[0185] Tissue type information can enable certain diagnoses and is therefore medically advantageous. The at least one electronic circuit is configured, for example, to control a light source to couple the light into the at least one optical fiber in synchronization with the scanning of the surrounding area with at least one of the at least one scan pattern.

[0186] In this way, light can be directed to specific areas of the environment while preventing light from being emitted in other areas. This can protect certain sensitive objects in the examination area.

[0187] The at least one electronic circuit can, for example, be configured to control the light source such that a light pattern is projected onto the area surrounding the proximal end of the optical probe.

[0188] This makes it possible, for example, to perform 3D measurements based on a distortion of the light pattern. This allows for increased information about the surroundings or the area under examination to be obtained, which is helpful for improved diagnoses.

[0189] The at least one electronic circuit is further configured to control the light source based on the topography information so that distortions of the light pattern due to the topography are reduced.

[0190] In this way, the light pattern can serve as a reference for certain actions during a surgical procedure.

[0191] The light source can be configured for laser coagulation, for example. Laser coagulation is a preferred surgical technique.

[0192] The at least one electronic circuit can further be configured to control the light source based on the tissue type information. For example, during laser coagulation, this can ensure that sensitive tissue is not subject to the surgical procedure.

[0193] The at least one electronic circuit may further be configured to determine at least one of the at least one scan pattern used for laser coagulation based on the tissue type indication.

[0194] This allows for targeted scanning of the surrounding regions of the examination area that are subject to laser coagulation. Other regions do not need to be scanned, which can reduce the time required for laser coagulation. In some examples, the at least one optical fiber comprises at least one multi-core fiber. Multi-core fibers can, for example, conduct light of different wavelengths. This allows different modalities to be supported without the need for multiple fibers. This reduces the size of the optical probe.

[0195] It would be possible for the optical probe to have a coupler at its proximal end, configured to couple light from different sources into different cores of the at least one multi-core fiber. The different sources can be associated with different modalities. The coupler allows, for example, different modalities to be performed in parallel. This reduces the time required for the procedure or measurement.

[0196] It would be conceivable for the at least one optical fiber to comprise at least one multi-clad fiber. Multi-clad fibers can, for example, guide light of different wavelengths. This allows different modalities to be supported without the need for multiple fibers. This reduces the size of the optical probe.

[0197] It would be conceivable for the optical probe to have a coupler at its proximal end, configured to couple light from different sources into different claddings of the at least one multi-clad fiber. The coupler, for example, allows different modalities to be performed in parallel. This reduces the time required for the procedure or measurement.

[0198] The at least one optical fiber can comprise a single-mode fiber. A single-mode fiber has a comparatively small cross-section. This allows the size of the optical probe to be reduced.

[0199] The ophthalmic surgical system may further comprise a plurality of light sources configured to generate light of different wavelengths.

[0200] It would be conceivable that different measurement modalities would be possible.

[0201] For example, it would be conceivable for the optical probe to have a coupler at its proximal end, designed to couple the light of different wavelengths into the same one of the at least one optical fiber. The coupler could, for example, allow different modalities to be performed in parallel. This reduces the time required for the procedure or measurement.

[0202] The optical probe can have at least one lens associated with the at least one optical fiber at the distal end. Using such a lens, light can be coupled out of the at least one optical fiber particularly efficiently. Using the at least one lens, the light can be coupled out of the at least one optical fiber with a relatively low divergence. This can increase the lateral resolution of a scan.

[0203] The lens, for example, is a gradient index lens.

[0204] These are easy to build and compact.

[0205] The lens, for example, is a spherical lens.

[0206] Spherical lenses have particularly good optical properties.

[0207] The lens, for example, is a converging lens.

[0208] In this way, the divergence can be reduced.

[0209] The actuator mechanism can comprise a deformability gradient of the elastic sheath in the circumferential direction at the distal end. The deformability gradient can enable a targeted curvature in a specific preferred direction, which is defined in this way.

[0210] The actuator mechanism can include a tendon-like pull-type actuator, which can be integrated in a particularly compact manner.

[0211] The tendon-like tension mechanism could involve two antagonistic tension tendons. This allows the curvature to be adjusted very precisely.

[0212] The actuator mechanism can comprise a shape-memory material on the elastic sheath. Such an actuator mechanism can be manufactured particularly compactly. For example, it is not necessary to route one or more tension tendons to the proximal end.

[0213] It would be possible for light to be detected via the at least one optical fiber after interacting with the surroundings. This means that the reception path also runs via the at least one optical fiber. This could, for example, reduce background light.

[0214] It would be possible for light to be detected via a different optical path after interaction with the environment. The reception path therefore does not have to run via an optical fiber. This avoids the low efficiency of coupling light from the environment into the optical fiber. Of course, the features of the previously described embodiments and aspects of the invention can be combined with one another. In particular, the features can be used not only in the described combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0215] For example, aspects were described above in which the actuator mechanism is automatically actuated by means of a motorized actuator. However, various aspects of the disclosure described herein are also applicable to techniques in which the actuator mechanism is manually actuated. This particularly concerns, for example, the geometric design of the optical probe or certain properties of the optical probe, such as the design of the actuator mechanism itself.

[0216] For example, techniques were described above in which primary light is guided through an optical fiber from the proximal end of the optical probe to the distal end. Correspondingly, it would also be conceivable to guide light through the optical fiber from the distal end to the proximal end. This could, for example, be secondary light which is coupled into the optical fiber after interacting with the environment of the optical probe. However, it is not necessary in all variants that such light from the environment of the optical probe is detected via an optical fiber of the optical probe. It would also be conceivable, for example, for secondary light to be detected via a different optical path that does not run through an optical fiber of the optical probe.

[0217] LIST OF REFERENCE SYMBOLS

[0218] 50 Examination area

[0219] 51 Environment

[0220] 52 Narrow access

[0221] 59 bulge

[0222] 60 Optical probe

[0223] 61 Proximal end

[0224] 62 Distal end

[0225] 71 Light

[0226] 72 Secondary Light

[0227] 81 First vertical movement

[0228] 82 Second vertical movement

[0229] 83 Longitudinal movement

[0230] 85 First rotational movement

[0231] 86 Second rotational movement

[0232] 87 Third rotational movement

[0233] 90 Actuator mechanism

[0234] 91 Curvature

[0235] 100 Ophthalmic Surgical System

[0236] 121 Motorized Actuator

[0237] 122 Robotic pick-up device

[0238] 123 Optical device

[0239] 125 control unit

[0240] 131 cover

[0241] 132 Optical Fiber

[0242] 139 lens

[0243] 160 Reference point 210, 210-1 , 210-2, 210-3 Scan pattern

[0244] 211 , 211-1 , 211-2, 211-2 starting point

[0245] 212 measuring point

[0246] 225 Azimuthal angle

[0247] 226 Polar angle

[0248] 904 Box

[0249] 905 Box

[0250] 906 Box

[0251] 910 Box

[0252] 915 Box

[0253] 920 Box

[0254] 921 Box

[0255] 930 Box

[0256] 932 Box

[0257] 935 Box

[0258] 940 Box

[0259] 1901 retina

[0260] 1902 cornea

[0261] 1903 Iris

[0262] 1904 lens

[0263] 1905 Retinal blood vessels

[0264] 1906 Macula

[0265] 1980 Study area

Claims

PATENT CLAIMS 1. Ophthalmic surgical system (100) for examining an examination area (1980), which comprises: - an optical probe (60) having a proximal end (61) and a distal end (62) and comprising at least one optical fiber (132) extending from the proximal end (61) to the distal end (62), a deformable sheath (131) surrounding the at least one optical fiber (132), and an actuator mechanism (90) configured to effect an adjustable beam deflection of light (71) coupled out of the optical fiber (132) by means of an adjustable curvature (91) of the at least one optical fiber (132) and the deformable sheath (131), - a motorized actuator (121) arranged to actuate the actuator mechanism (90), and - at least one electronic circuit (125) configured to determine control signals for the motorized actuator (121) based on at least one predetermined scanning pattern (210, 210-1, 210-2, 210-3) and to output these to the motorized actuator (121), whereby the beam deflection can be successively changed such that the coupled-out light scans an environment (51) of the optical probe at the distal end with the at least one predetermined scanning pattern (210, 210-1, 210-2, 210-3).

2. Ophthalmic surgical system (100) according to claim 1, further comprising: - a robotic pickup device (122) configured to position the optical probe (60), wherein the at least one electronic circuit (125) is configured to further determine control signals for the robotic pickup device (122) based on the at least one predetermined scan pattern (210, 210-1, 210-2, 210-3) and to output them to the robotic pickup device (122).

3. The ophthalmic surgical system (100) of claim 2, wherein the at least one electronic circuit (125) is configured to determine the control signals for the robotic pickup device (122) such that the optical fiber (132) passes through a fixed reference point (160) independently of the successive change in the beam deflection for scanning the at least one scan pattern (210, 210-1, 210-2, 210-3).

4. Ophthalmic surgical system (100) according to one of the preceding claims, wherein the at least one electronic circuit (125) is configured to to determine an estimate of the beam deflection based on a model of the optical probe (60).

5. The ophthalmic surgical system (100) of claim 4, wherein the at least one electronic circuit (125) is configured to determine the control signals for the motorized actuator (121) and / or control signals for a robotic pickup device (122) configured to position the optical probe (60) based on the beam deflection estimate.

6. The ophthalmic surgical system (100) of claim 4 or 5, wherein the ophthalmic surgical system comprises a plurality of optical fibers (132), wherein the model models a relative movement of the plurality of optical fibers to one another.

7. The ophthalmic surgical system (100) of any one of claims 4 to 6, wherein the model models dynamic effects of movement of the at least one optical fiber.

8. Ophthalmic surgical system (100) according to one of the preceding claims, wherein the at least one electronic circuit (125) is configured to control an optical measuring device (123) to perform distance measurements along at least one of the at least one predetermined scanning pattern (210, 210-1, 210-2, 210-3) based on the light (71).

9. The ophthalmic surgical system (100) of claim 8, wherein the at least one electronic circuit (125) is configured to control a light source based on the distance measurements, so that the light source couples further light into the at least one optical fiber (132) with a light intensity determined as a function of the distance measurements.

10. The ophthalmic surgical system (100) of claim 8 or 9, wherein the distance measurements comprise tomographic measurements.

11. The ophthalmic surgical system (100) according to any one of claims 8 to 10, wherein the at least one electronic circuit (125) is configured to determine a topographical indication in a map of the surroundings based on the distance measurements.

12. The ophthalmic surgical system (100) of any one of claims 8 to 11, wherein the at least one electronic circuit (125) is configured to determine an estimate of the beam deflection based on a model of the optical probe.

13. The ophthalmic surgical system (100) of claim 12, wherein the at least one electronic circuit is configured to determine a map of the environment based on the estimate of the beam deflection, wherein the at least one electronic circuit (125) is further configured to determine, based on the map of the environment, one or more blocking regions into which the optical probe (60) should not penetrate.

14. Ophthalmic surgical system (100) according to one of the preceding claims, wherein the at least one electronic circuit (125) is configured to control an optical measuring device (123) to perform contrast measurements along at least one of the at least one predetermined scan pattern (210, 210-1, 210-2, 210-3) based on the light (71).

15. Ophthalmic surgical system (100) according to one of the preceding claims, wherein the at least one electronic circuit (125) is configured to control a light source in order to couple the light into the at least one optical fiber (132) synchronized with the scanning of the surroundings with at least one of the at least one predetermined scan pattern (210, 210-1, 210-2, 210-3).

16. The ophthalmic surgical system (100) of claim 15, wherein the at least one electronic circuit (125) is configured to control the light source such that a light pattern is projected onto the area surrounding the proximal end of the optical probe (60).

17. Ophthalmic surgical system (100) according to claim 11 and claim 16, wherein the at least one electronic circuit (125) is further configured to To control the light source based on the topography information in the map of the surrounding area, so that distortions of the light pattern due to the topography are reduced.

18. The ophthalmic surgical system (100) of claim 15, wherein the light source is configured for laser coagulation.

19. Ophthalmic surgical system (100) according to one of the preceding claims, wherein the at least one optical fiber (132) comprises at least one multi-core fiber.

20. The ophthalmic surgical system (100) of any one of the preceding claims, wherein the at least one optical fiber (132) comprises at least one multi-clad fiber.

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