Surgical robot system for ophthalmic surgery and its control

Abstract

A surgical robotic system for use in an ophthalmic surgical procedure is provided. The system includes a surgical arm (080) including a movable arm portion (082), the surgical arm (080) including an instrument connector for attaching a surgical instrument (119) having a longitudinal axis. The movable arm portion (082) has at least one degree of freedom that allows longitudinal movement of the surgical instrument (119) along its longitudinal axis toward or away from an ophthalmic surgical target (123). The system includes a sensor (030), a user interface (020), an actuator (060), and a processor subsystem (040). The processor subsystem (040) is configured to acquire sensor data (032) from the sensor (030) at an initial position of the surgical instrument (119), determine an initial distance between the surgical instrument (119) and the surgical target (123), acquire data indicative of a target position of the surgical instrument (119), determine a displacement distance, output a sensory perceptible representation of the displacement distance, receive a confirmation signal from a user, and upon receiving the confirmation signal, control the actuator (060) to actuate the movable arm portion (082) to cause a single movement of the surgical instrument (119) over the displacement distance.

Description

Technical Field

[0001] The present invention relates to a surgical robot system for use in ophthalmic surgical procedures. The present invention further relates to a method of controlling a surgical robot system during use in an ophthalmic surgical procedure, and a computer program product comprising instructions for causing a processor system to execute the method.

Background Art

[0002] In ophthalmic surgical procedures, the use of surgical robot systems has become increasingly common. Such surgical robot systems do not operate completely autonomously, but are typically at least partially under the control of a human operator, for example to control the movement of a surgical instrument attached to the surgical arm of the surgical robot system. Thus, a surgical robot system can assist a human operator in performing a surgical procedure.

[0003] With robot assistance, the operating accuracy of moving a surgical instrument can be improved. Given the complexity and size of the tissues and structures found within or around the eye, high precision is particularly required in ophthalmic surgery. However, a robot system provides such precision in absolute coordinates, not with respect to the tissue. For example, tissue variations or movements can reduce the precision provided by robot assistance. Furthermore, the surgeon operating the robot has only a limited view of the surgical field through the microscope. In particular, depth perception becomes difficult.

[0004] There exist existing surgical robotic systems that include a movable arm portion, and the movable arm portion may include a surgical arm that includes an instrument connector for attaching a surgical instrument. Accordingly, the surgical instrument can be positioned by the surgical arm. To control the movement of the surgical instrument, a human-machine interface for receiving positioning commands from a human operator may be provided. An actuator may be provided to operate the movable arm portion to cause the movement of the surgical instrument in accordance with the positioning commands provided by the human operator. Examples of this approach can be found in the field of teleoperation where a human operator can operate a master device, such as a motion controller, to provide positioning commands to a slave device, such as the aforementioned surgical arm.

[0005] However, such systems do not reliably provide the level of accuracy required for ophthalmic surgical procedures and typically mitigate issues by processing position commands received from the user, such as to reduce the effects of hand tremors.

[0006] U.S. Patent Application Publication No. 20190110682 (A1) introduces the use of an optical coherence tomography (OCT) sensor to detect when a surgical injector penetrates a desired tissue layer of the eye in vitreoretinal surgical applications. The OCT sensor is used to scan the surgical target. For example, it receives instructions from the user to identify the tissue layer to receive the injection or to confirm an automatic injection. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The problem of fully automating the movement of a surgical instrument towards a surgical target is that such movement may be based on noisy or otherwise unreliable sensor data. For this reason, users (typically surgeons) have historically had concerns regarding the adoption of fully automated procedures. For example, when the surgical target is in a subretinal position, movement of the eye or the surgical instrument may result in less reliable sensor measurements indicating the position of the surgical target, or if the sensor is partially or completely obscured, for example by tissue fragments, it introduces the risk of the surgical instrument puncturing unintended tissue or organs.

Means for Solving the Problem

[0008] One of the objectives of the present invention is to obtain a surgical robot system and / or a method for controlling a surgical robot system that enables a user to control the displacement of a surgical instrument while still maintaining the advantages of automatic movement, including reducing the effects of hand tremors or vibrations. By giving the user control over the displacement of the surgical instrument, it also addresses the user's fundamental concerns regarding the adoption of automated procedures. This combination of automatic movement and user control over instrument displacement improves the reliability of the surgical robot system.

[0009] A first aspect of the present invention is a surgical robot system for use in ophthalmic surgical procedures, comprising: - A surgical arm including a movable arm portion, the movable arm portion including an instrument connector for attaching a surgical instrument having a longitudinal axis, the movable arm portion having at least one degree of freedom enabling longitudinal movement of the surgical instrument along the longitudinal axis of the surgical instrument towards or away from an ophthalmic surgical target, the surgical arm; - A sensor configured to acquire sensor data indicating the distance between the surgical instrument and the surgical target; - A user interface configured to receive user input from a user and output a sensory Perceived as possible None output to the user. - An actuator configured and arranged to actuate a movable arm portion to cause longitudinal movement of a surgical instrument; - A processor subsystem, - At an initial position of the surgical instrument, obtain sensor data from a sensor, and based on the sensor data, determine an initial distance between the surgical instrument and the surgical target; - Obtain data indicating a target position of the surgical instrument relative to the surgical target; - Based on the sensor data and the target position, determine a displacement distance of the surgical instrument; - Via a user interface, sense a determined displacement distance Perceived as possible None Output the representation; - Receive a confirmation signal from a user via a user interface; - When the confirmation signal is received, control the actuator to actuate the movable arm portion to cause a single movement of the surgical instrument along the longitudinal axis over the determined displacement distance; A processor subsystem configured as such; To provide a surgical robot system including.

[0010] In a further aspect of the present invention, a computer-implemented method for controlling a surgical robot system during use in an ophthalmic surgical procedure, the surgical robot system including a surgical arm, the surgical arm including a movable arm portion, the movable arm portion including an instrument connector for attaching a surgical instrument having a longitudinal axis, the movable arm portion having at least one degree of freedom enabling longitudinal movement of the surgical instrument along the longitudinal axis of the surgical instrument towards or away from an ophthalmic surgical target, the surgical robot system further including an actuator configured and arranged to actuate the movable arm portion to cause longitudinal movement of the surgical instrument, the method comprising: - At an initial position of the surgical instrument, obtain sensor data indicating the distance between the surgical instrument and the surgical target; - Based on the sensor data, determining an initial distance between the surgical instrument at the initial position and the surgical target; - Obtaining data indicating the target position of the surgical instrument relative to the surgical target; - Based on the sensor data and the target position, determining the displacement distance of the surgical instrument; - Sensation of the displacement distance Perceived as Possible None - Outputting a representation to the user; - Receiving a confirmation signal from the user; - When receiving the confirmation signal, controlling the actuator to activate the movable arm portion to cause a single movement of the surgical instrument along the longitudinal axis over the displacement distance; A computer-implemented method is provided that includes the above.

[0011] In a further aspect of the present invention, a computer program product is provided that includes instructions for causing a processor system to execute the method.

[0012] The above aspect of the present invention includes a surgical robot system including a surgical arm. The surgical arm includes a movable arm portion, and the movable arm portion includes an instrument connector for attaching a surgical instrument. The surgical instrument typically has a longitudinal axis passing through the tip of the surgical instrument. The movable arm portion has at least one degree of freedom (DoF: Degree-of-Freedom) that enables longitudinal movement of the surgical instrument along the longitudinal axis of the surgical instrument towards the surgical target. The surgical target can be the surface of such a layer, such as, for example, a tissue layer or the surface of the supraretinal layer. It should be noted that the movable arm portion may have only one DoF aligned with the longitudinal axis of the surgical instrument to enable the longitudinal movement. However, the movable arm portion may also have a plurality of DoFs that enable the longitudinal movement, but it is not necessary for each DoF to be individually aligned with the longitudinal axis. A surgical arm having the functions described in this paragraph is known per se in the field of medical robots and is also known as an instrument manipulator, a robotic arm, a surgical robot slave device, etc.

[0013] The user interface is provided to receive user input such as a positioning command from the user and output a sensory Perceived as possible None output to the user. Further, an actuator is provided to operate the movable arm portion to cause longitudinal movement of the surgical instrument. Another term for the actuator is a drive mechanism. Further, a sensor is provided to acquire sensor data indicating the distance between the surgical instrument, for example, the tip of the surgical instrument and the surgical target.

[0014] The processor subsystem is provided to control an actuator to operate a movable arm portion to move a surgical instrument along a longitudinal axis. At an initial position of the surgical instrument, the processor subsystem may obtain sensor data from a sensor and determine an initial distance between the surgical instrument and the surgical target. The processor subsystem may obtain data indicating a target position of the surgical instrument relative to the surgical target. For example, the data indicating the target position may be obtained from a user in the form of a user input or may be automatically determined based on detection of a specific anatomical structure or the like. The target position may be the position of the surgical target or another position, for example, between the surgical target and the initial position of the surgical instrument. The processor subsystem may determine a displacement distance of the surgical instrument based on the sensor data and the target position. For example, the displacement distance may be the distance that the surgical instrument moves in a single first movement. The processor subsystem may output a perceptible representation of the determined displacement. Perceptible Perceived as Possible None representation Perceived as Possible NoneThe presentation may be, for example, an audio output indicating a determined displacement distance, an acoustic output indicating proximity, a graphical output such as an overlay on an image inside the eye with the determined displacement distance attached, or a text output such as a visual output of a number representing the determined displacement distance, a tactile feedback, etc. Thus, the user can confirm the determined displacement distance, and the processor subsystem can receive a confirmation signal via the user interface. The confirmation signal may be any type of user input indicating that the user has confirmed the determined displacement distance, including a voice command, such as a click of a button on a graphical user interface. When the confirmation signal is received, the processor subsystem may control the actuator to activate the movable arm portion to cause a single movement of the surgical instrument along the longitudinal axis over the determined displacement distance. That is, the user confirms the distance by which the surgical instrument moves. Here, the term "single movement" can also be considered as a single fluid movement without a pause or a temporary stop that interrupts the movement. The term "longitudinal movement towards or away from the surgical target" refers to the forward movement of the surgical instrument or the backward movement of the surgical instrument.

[0015] By determining the displacement distance of a surgical instrument, a user (e.g., a surgeon) can maintain control over the placement and advancement of the surgical instrument while performing movements in an automated manner when performing surgery inside or on the eye. Since the measurement values are based on sensor data, there is a risk that the sensor data is too noisy to provide reliable measurement values. As a result, an inappropriate distance may be calculated. By having the user approve the determined displacement distance before a single movement of the surgical instrument is executed, the user is provided with an opportunity to prevent the movement of the surgical instrument if the sensor data is inappropriate or inaccurate. That is, the user is required to confirm the next step of the movement of the surgical instrument before the movement is executed. The determined displacement distance is notified to the user, and the user is requested to confirm the determined displacement distance. By doing so, if the determined displacement distance is inappropriate, the user can disapprove the determined displacement distance. This enables the user to maintain control over the procedure while the movement of the surgical instrument itself is being executed in an automated manner, reducing or eliminating risks associated with manual injection, such as hand tremors or shakes. Further, the displacement distance by which the surgical instrument moves in a single movement is determined after sensor data indicating the distance measurement value is acquired, and the sensor data is preferably acquired while the surgical instrument is stationary. This may improve the reliability of the sensor measurement values, particularly when the sensor data is acquired while the surgical instrument is in a stationary position.

[0016] Optionally, when the processor subsystem completes a single movement of the surgical instrument, it obtains the latest sensor data from the sensor, determines the remaining distance between the surgical instrument and the surgical target based on the latest sensor data, determines whether the target position has been reached based on the determined remaining distance, and if not reached, controls the actuator to correct the depth of the surgical instrument based on the determined remaining distance. Thus, any movement of the eye or intraocular structures due to, for example, changes in intraocular pressure, respiration, patient movement, or reaction to movement of the surgical instrument that may move the target position and / or the surgical target can be taken into account. Further, the latest sensor data may provide more reliable measurements when the initial measurements are partially or completely obscured, for example, by tissue fragments or other structures or tissues within or around the eye. The latest sensor data may be obtained while the surgical instrument is at a different position that may be closer to the surgical target and may have less noise.

[0017] Optionally, the processor subsystem determines a correction displacement distance to reach the target position from the determined remaining distance to the surgical target, and via the user interface, a perception of the correction displacement distance Perceived as possible None representation is output, a further confirmation signal is received from the user via the user interface, and upon receiving the further confirmation signal, the actuator is controlled to actuate the movable arm portion to cause a further single movement of the surgical instrument along the longitudinal axis over the correction displacement distance, so as to correct the depth of the surgical instrument, the actuator may be controlled in a displacement-based control mode. In this correction procedure, the latest sensor data is obtained before the surgical instrument moves to correct its position. Thereafter, after the latest sensor data is obtained, the correction displacement distance is determined. The user is again requested to confirm the determined correction displacement distance, providing a further opportunity to ensure that the distance the surgical instrument moves is reasonable. Thus, this improves the safety and reliability of further steps of movement of the surgical instrument.

[0018] Optionally, the processor subsystem may control the actuator in a limited closed-loop control mode that corrects the depth of the surgical instrument using the latest sensor data. The limited closed-loop control mode is limited by at least one of: a predefined duration of use of the limited closed-loop control mode, a predefined maximum correction displacement distance, the need for a certainty score to remain above a certainty score threshold during correction (the certainty score represents the certainty of the determined remaining distance), the need for continuous user input during correction, and stopping the movement of the surgical instrument when it is detected that the continuous user input has ended. Thus, in this mode, the level of automation of the system is controlled by the factors described above, thereby preventing a fully automated system that the user may not immediately adopt while still providing the advantages in the movement of the automated process. For example, the requirement that the certainty score exceeds the threshold allows the movement of the surgical instrument to be automated when the sensor data is sufficiently reliable, preventing automatic movement when the sensor data is unreliable, which could lead to overshooting the target position or not reaching the target position. Requiring continuous user input during correction can ensure that the user is involved and paying attention. Time or displacement limits can similarly limit the degree to which the surgical robotic system is automated. For example, the automatic movement of the surgical instrument may stop after a certain amount of time or after a certain displacement and may then resume, for example, based on the latest sensor data. Thus, this limited level of automation of the system may improve the safety of the patient during the surgical procedure.

[0019] Optionally, the processor subsystem may calculate a confidence score representing the certainty of a determined distance between the surgical instrument and the surgical target, and adapt the control of the actuator according to the calculated confidence score. The confidence score may be based on at least one of an estimated value of the measurement noise of the sensor, detection of the presence of dynamic movement of the surgical target, comparison of the sensor data with a model representing a reference of the sensor data, and comparison between the estimated surgical target position and the predicted surgical target position, where the predicted surgical target position is based on the instrument movement measured by at least one position sensor. For example, when the confidence score is high, the speed of the surgical instrument may be increased, and when the confidence score is low, the speed of the surgical instrument may be decreased. In this way, the procedure may progress more rapidly when the reliability of the sensor data is higher (e.g., high confidence score), thereby potentially reducing the time required for the surgical procedure (and thus the patient's prolonged discomfort), and the surgical instrument may move more slowly when the reliability of the sensor data is low, potentially preventing the surgical instrument from extending beyond the surgical target. The use of the confidence score and the adaptation of the actuator control according to the confidence score enables the user (e.g., the surgeon) to determine when more manual control is required to ensure patient safety and surgical accuracy and when a more automated approach can be utilized, thereby potentially speeding up the procedure and reducing the patient's discomfort.

[0020] Optionally, the processor subsystem may repeatedly calculate a confidence score, and if the calculated confidence score falls below a confidence score threshold, it may execute an interruption procedure. The interruption procedure may include at least one of the following: retracting the surgical instrument, temporarily stopping the movement of the surgical instrument, controlling the actuator in a restricted closed-loop control mode, and switching the actuator to be controlled by a motion controller-based control model. The processor subsystem may control the actuator according to a position control command received from the user via the motion controller. By repeatedly calculating the confidence score, it is possible to prevent the advancement of the movement of the surgical instrument when the sensor data is too noisy or unreliable, thereby reducing the risk of unintended movement of the surgical instrument and damage to intraocular or supraocular structures.

[0021] Optionally, the processor subsystem may select a control mode from a series of control modes based on the calculated confidence score. The series of control modes includes at least two of a motion controller-based control mode, a displacement-based control mode, and a restricted closed-loop control mode. In the motion controller-based control mode, the processor subsystem may control the actuator according to a position control command received from the user via the motion controller of the user interface. In the displacement-based control mode, the processor subsystem determines a correction displacement distance to reach the target position from the determined remaining distance to the surgical target and provides a sense of the correction displacement distance via the user interface. Perceived as Possible NoneOutputs a representation, receives a further confirmation signal from the user via a user interface, and controls an actuator to activate a movable arm portion to cause a further single movement of a surgical instrument along a longitudinal axis over a correction displacement distance when the further confirmation signal is received. In a restricted closed-loop control mode, the processor subsystem is limited by at least one of a predefined duration of use of the restricted closed-loop control mode, a predefined maximum correction displacement distance, a requirement that a certainty score remains above a certainty score threshold during correction (the certainty score represents the certainty of the remaining distance determined), a requirement for continuous user input during correction, and stopping the movement of the surgical instrument when it is detected that the continuous user input has ended. By using the certainty score to select a control mode, it can be ensured that, for example, when the certainty score is low, the involvement of user input increases, while in some cases, for example, when the certainty score is high, the degree of automation is increased.

[0022] Optionally, before receiving a confirmation signal from the user, the processor subsystem outputs a sense of the calculated certainty score via the user interface. Perceived as Possible None It may output a representation. A sense of the certainty score Perceived as Possible None Providing the representation to the user indicates the level of certainty associated with the sensor measurements and enables the user to either confirm or reject the progress of the procedure. For example, if the certainty score indicates a low level of certainty, the user may decide not to continue with a single movement of the surgical instrument and / or may decide to update the sensor data again.

[0023] Optionally, the sensor includes at least one of an optical coherence tomography (OCT) sensor configured to optically couple to an optical fiber attached to or incorporated in a surgical instrument, an intraoperative optical coherence tomography (iOCT) via a microscope, a stereo camera via a microscope, an interferometer sensor incorporated in a surgical instrument, a time-of-flight sensor incorporated in a surgical instrument, and an ultrasonic sensor incorporated in a surgical instrument.

[0024] Optionally, the processor subsystem further obtains sensor data indicating the distance between a first layer of eye tissue and a second layer of eye tissue, and the surgical target is between the first layer and the second layer, and the surgical instrument is configured to correct the position of the surgical instrument such that it is between the first layer and the second layer. By determining the distances from the surgical instrument and each of the first and second layers respectively, the system may determine whether the surgical instrument is between the two layers. Thereby, the positioning of the surgical instrument can be improved.

[0025] Optionally, the processor subsystem may obtain sensor data indicating the distance between a first layer of eye tissue and a second layer of eye tissue, the surgical target is between the first layer and the second layer, and the data indicating the target position of the surgical instrument relative to the surgical target includes data indicating the distance between the first layer and the second layer. By determining the distance between tissue layers, the accuracy of positioning the surgical instrument can be improved.

[0026] Those skilled in the art will understand that two or more of the above-described embodiments, implementations, and / or aspects of the present invention can be combined in any manner considered useful.

[0027] Methods and / or computer program products for accommodating the described modifications and changes to the surgical robot system can be carried out by those skilled in the art based on this specification.

[0028] The present invention is defined in the independent claims or clauses. Although advantageous, any embodiments are defined in the dependent claims or clauses.

[0029] These and other aspects of the present invention will be apparent from, and will be described with reference to, the embodiments described below.

Brief Description of the Drawings

[0030]

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DETAILED DESCRIPTION OF THE INVENTION

[0031] Note that items having the same reference numerals in different figures have the same structural features and the same functions, or are the same signals. If the functions and / or structures of such items have been described, there is no need to repeat that description in the detailed description.

[0032] List of reference numerals The following list of reference numerals is provided to assist in the interpretation of the drawings and is not to be construed as limiting the claims or sections. 020 User interface 022 User input 030 Sensor 032 Sensor data 040 Processor subsystem 042 Actuation command 060 Actuator 062 Actuation of the surgical arm 080 Surgical arm 082 Movable arm portion 100 Surgical robot system 101 e → 1. Axes of the Cartesian coordinate system 102 e → y , Axes of the Cartesian coordinate system 103 e → z , Axes of the Cartesian coordinate system 104 e → x The axes of the coordinate system fixed to the instrument tip that are orthogonal to the instrument longitudinal axis 105 e → y The axes of the coordinate system fixed to the instrument tip that are orthogonal to the instrument longitudinal axis 106 e → z The axes of the Cartesian coordinate system aligned with the instrument longitudinal axis 107 φ, the rotation of the surgical instrument that laterally displaces its tip 108 ψ, the rotation of the surgical instrument that laterally displaces its tip 109 z, the translation of the surgical instrument in the longitudinal direction (along its longitudinal axis), or the penetration direction, or the advancement direction 110 θ, the rotation of the surgical instrument about its longitudinal axis 111 Φ, the rotational degree of freedom of the movable arm portion 112 Ψ, the rotational degree of freedom of the movable arm portion 113 Ζ, the translational degree of freedom of the movable arm portion 114 Θ, the rotational degree of freedom of the movable arm portion 115 Φ m The rotational degree of freedom of the motion controller 116 Ψ m The rotational degree of freedom of the motion controller 117 Ζ m The translational degree of freedom of the motion controller 118 Θ m The rotational degree of freedom of the motion controller 119 Surgical instrument 121 Distance sensor 122 Surgical instrument tip 123 Surgical target 124 Trocar 125 Remote center of motion (RCM) 126 Button on the motion controller gripper 127 Light beam 200 Eye 210 Retina 220 First layer of tissue 230 Second layer of tissue 240 Breves 700 Method for Selecting a Control Mode 710 Calculate a Certainty Score 720 Compare the Certainty Score with a First Threshold 730 Decision Block 740 Select a Motion Controller - Based Control Mode 744 Compare the Certainty Score with a Second Threshold 746 Decision Block 750 Select a Displacement - Based Control Mode 760 Select a Restricted Closed - Loop Control Mode 810 Motion Controller - Based Control Mode 820 Displacement - Based Control Mode 830 Restricted Closed - Loop Control Mode 840 Interrupt Procedure 900 Method for Triggering an Interrupt Procedure 910 Calculate a Certainty Score 920 Compare the Certainty Score with a Threshold 940a Continue the Movement of the Surgical Instrument 940b Continue the Ophthalmic Surgical Procedure 950 Perform the Interrupt Procedure 1100 Method for Controlling a Surgical Robot System 1110 Acquire Sensor Data 1120 Determine an Initial Distance 1130 Acquire a Target Position with Respect to the Surgical Target 1140 Determine a Displacement Distance 1150 Output the Displacement Distance 1160 Receive User Confirmation 1170 Actuate the Movable Arm to Move in a Single Movement 1150 Non - Transitory Program Code 1160 Computer - Readable Medium

[0033] Figure 1 schematically shows a surgical robot system 100 for use in a surgical procedure. The surgical robot system 100 includes a surgical arm 080. The surgical arm 080 includes a movable arm portion 082, and the movable arm portion includes an instrument connector 119 for attaching a surgical instrument. Figure 1 shows a surgical instrument 119 attached to the instrument connector (for simplicity, the instrument connector is not shown separately in Figure 1). The movable arm portion 082 has at least one degree of freedom (DoF) that enables longitudinal movement of the surgical instrument toward the surgical target. Here, longitudinal movement refers to the movement of the surgical instrument 119 along its longitudinal axis (for simplicity, the longitudinal axis is not shown separately in Figure 1).

[0034] The surgical robot system 100 further includes a user interface 020 for receiving input from a user. The user input 022 may include positioning commands, confirmatory inputs indicating to continue a procedure or a step of a procedure from a human operator, such as a surgeon or a medical provider, for controlling the longitudinal movement of the surgical instrument, and / or input information such as indicating operating parameters and / or displaying the surgical target position. Examples of the user interface include, but are not limited to, a keyboard, a mouse, a touch-sensing surface, a joystick, a foot pedal, a microphone, a gesture recognition system, etc. The user interface may use any suitable input mode such as touch, push action, voice command, eye movement, gesture recognition, etc.

[0035] The surgical robot system 100 further includes an actuator 060 configured and arranged to operate a movable arm portion to cause longitudinal movement of a surgical instrument. The actuator 060 can be any suitable actuator from, for example, actuators in the field of surgical robots or in a more general field. In particular, the actuator can be one of a plurality of actuators that together provide the operation of the movable arm portion 060 along at least one DoF. That is, the surgical robot system 100 may include a plurality of actuators, for example, to provide operation along a plurality of DoFs. Thus, it will be understood that any reference to the configuration of the actuator 080 can be understood as a reference to the (connected) configuration of such a plurality of actuators. FIG. 1 schematically shows the operation of the surgical arm 080, that is, as a dashed line 062. Although shown separately from the surgical arm 080, it should be noted that the actuator 060 may be built into or attached to the surgical arm 080.

[0036] The surgical robot system 100 further includes a sensor 030 configured and arranged to acquire sensor data 032 indicating the distance between the surgical instrument 119 and the surgical target. The sensor 030 may include at least one of an optical coherence tomography (OCT) sensor configured to optically couple to an optical fiber attached to or incorporated in the surgical instrument 119, an intraoperative optical coherence tomograph (iOCT) via a microscope, a stereo camera via a microscope, an interferometer sensor incorporated in or attached to the surgical instrument 119, a time-of-flight sensor incorporated in or attached to the surgical instrument 119, and an ultrasonic sensor incorporated in or attached to the surgical instrument 119. The surgical instrument may be a perfusion / suction instrument for perfusing or suctioning a fluid at a desired target position, a photocoagulation instrument for applying light energy at a desired distance from the target, a vitrectomy instrument for excising and suctioning the vitreous humor or other fluid at a desired distance from the target, a tissue manipulation instrument that needs to be accurately placed at a first interface of the tissue, and the like. In some embodiments, the surgical robot system 100 may include a microscope configured to provide, for example, a stereo camera and / or an iOCT. In some embodiments, the microscope may be communicatively coupled to the surgical robot system 100. In some embodiments, the sensor data 032 may include line measurements and may include an A-scan defined as an intensity as a function of distance, a B-scan forming a two-dimensional image, a C-scan by, for example, a plurality of B-scans, and the like. The distance may be derived from any of these scan types using, for example, image analysis. In some embodiments, the sensor 030 may include an optical sensor and the sensor data 032 may include diffuse reflectance. In some embodiments, the sensor 030 may include a stereo camera and the sensor data 032 may include two two-dimensional images for obtaining a depth map.

[0037] The surgical robot system 100 further includes a processor subsystem 040 configured to control an actuator to operate a movable arm portion and to move a surgical instrument 119 along a longitudinal axis. When the surgical instrument 119 is in an initial position, the processor subsystem 040 may obtain sensor data 032 from a sensor 030. The sensor data 032 may indicate the distance between the surgical instrument 119, e.g., the tip 122 (shown in FIG. 2) of the surgical instrument 119 and the surgical target 123 (shown in FIG. 2). In other words, the sensor data 032 can be used to determine the distance between the surgical instrument and the surgical target. In some embodiments, the sensor data 032 is obtained while the surgical instrument is stationary to improve the reliability of the measurement. In some embodiments, the sensor 030 may be configured to obtain sensor data 032 indicating the distance between multiple layers of eye tissue. That is, the sensor 030 may be configured to determine the distance between the surgical instrument and a first layer of tissue and the distance between the surgical instrument and a second layer of tissue.

[0038] The processor subsystem 040 may be configured to obtain data indicating a target position of a surgical instrument relative to a surgical target. The position of the surgical target itself may be identified, for example, from sensor data from an internal or external sensor, but alternatively or additionally, may also be identified by user input. Data indicating the target position may typically be obtained from user input, but alternatively or additionally, may also be automatically determined. Generally, the target position may be a relative position with respect to the surgical target. In some embodiments, the target position may be defined as a one-dimensional position along a line from the surgical instrument to the surgical target. That is, the target position may be defined as a longitudinal position. Such a target position may otherwise be referred to as, for example, "depth" if the target position extends beyond the surgical target longitudinally, or "proximity" if the target position is in front of the surgical target longitudinally. In some embodiments, the target position may be defined as a specified distance from the surgical target. Whether the target position is beyond or in front of the surgical target may be indicated by the sign of the specified distance. The target position may also have a three-dimensional position in any other coordinate system, such as a polar coordinate system or a Cartesian coordinate system. In some embodiments, the user may be required to graphically input the target position, for example, by providing an input on a graphical user interface, from which the processor subsystem 040 may then numerically determine the target position. In other embodiments, the user may be required to directly input the target position in numerical form, for example, by providing a numerical input indicating the distance relative to the surgical target. In some embodiments, if the surgical target is a layer of tissue, the target position may be provided as a relative position or depth from the layer of tissue. The layer of tissue may be, for example, a layer of vitreous tissue or a layer of retinal tissue.

[0039] The processor subsystem 040 may be configured to determine the displacement distance of the surgical instrument based on the sensor data and the target position. For example, the displacement distance may be a function of the difference between the initial position and the target position. In some embodiments, the displacement distance may be a partial distance between the initial position and the target position of the surgical instrument. In other embodiments, the displacement distance may be the total distance between the initial position and the target position of the surgical instrument.

[0040] The processor subsystem 040 may be configured to output a perception of the determined displacement distance via the user interface 020. Perceived as Possible None The perception of the determined displacement distance Perceived as Possible None The representation may include, for example, a graphical representation of the determined displacement distance visually overlaid on an image of the surgical field, an audio output via a speaker of the user interface 020, and / or a visual numerical output on a display of the user interface 020. The perception of the determined displacement distance Perceived as Possible None The representation may be rounded to a specified level of accuracy.

[0041] The processor subsystem 040 may be configured to receive a confirmation signal from the user via the user interface. The confirmation signal may be received, for example, as voice input via a microphone of the user interface 020, touch input or click input on a graphical user interface of the user interface 020, input to a motion controller, foot pedal input, gesture-based input via a camera of the user interface 020, etc. The user interface 020 may be configured to receive one or more types of input for the confirmation signal.

[0042] Upon receiving the confirmation signal, the processor subsystem 040 may be configured to control the actuator to actuate the movable arm portion to effect a single movement of the surgical instrument along the longitudinal axis over the determined displacement distance. That is, when the user confirms the determined displacement distance, the surgical instrument is moved over the determined displacement distance in a single continuous movement. The single movement of the surgical instrument may be referred to as a continuous movement or a non-interrupted movement. In some embodiments, the surgical instrument may move towards the surgical target only when the user confirms the determined displacement distance.

[0043] In some embodiments, the surgical robot system 100 may be configured to perform a correction procedure. Upon completion of the single movement of the surgical instrument, the processor subsystem 040 may be configured to obtain the latest sensor data 032 from the sensor 030 and determine the remaining distance between the surgical instrument and the surgical target based on the latest sensor data 030. In other words, after the surgical instrument has moved over the determined displacement distance to a second position, the latest sensor data is obtained while the surgical instrument is in the second position. In some embodiments, the latest sensor data is obtained while the surgical instrument is stationary to improve the reliability of the measurement. The processor subsystem 040 may be configured to determine whether the target position has been reached based on the determined remaining distance. If the processor subsystem 040 determines that the surgical instrument has not reached the target position, the processor subsystem 040 may control the actuator to correct the depth of the surgical instrument based on the determined remaining distance. In some cases, movement of the surgical instrument and / or the eye, such as a change in intraocular pressure or patient movement, may displace the target position. In some cases, the initial sensor measurements may be slightly inaccurate, leading to an inaccurate displacement distance and ultimately either the movement of the surgical instrument being too short or too long to reach the target position or overshooting the target position. In such cases, the depth, e.g., position, of the surgical instrument may be corrected based on the determined remaining distance.

[0044] The processor subsystem 040 may control the actuator in one or more control modes, which will be described in detail with reference to FIGS. 7-9, for example, based on a certainty score. In some embodiments, the control modes as described with reference to FIGS. 7-9 may be manually selected.

[0045] FIG. 2 shows a surgical instrument 119 passing through a trocar 124 during minimally invasive surgery. For example, in the case of vitreoretinal surgery, the trocar 124 may be placed in the sclera. To approach or penetrate the surgical target 123, rotation around the trocar and translation within the trocar may be possible with four degrees of freedom, for example, rotation φ107, rotation ψ108, rotation θ110, and translation z109. Further shown are the tip 122 of the surgical instrument 119 and the three axes 104-106 of the coordinate system fixed to the instrument tip 122,

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[0046] The surgical robot system 100 may be used in ophthalmic surgical procedures such as minimally invasive surgical procedures as described above. FIG. 3 shows a joint diagram showing the motion characteristics of the movable arm portion of the surgical arm for use in ophthalmic surgical procedures, particularly minimally invasive surgery. In the example of FIG. 3, the surgical robot system includes a surgical arm, and the surgical arm includes a movable arm portion having DoFs Φ111, Ψ112, Ζ113, and Θ114 that enable respective instrument motions 107 to 110 and cause movement of the surgical instrument tip 122. The DoFs can be arranged such that there is a point on the surgical instrument that does not move in space, referred to as the remote center of motion (RCM) 125. By moving the base of the surgical arm, the movable arm portion can be arranged such that its RCM 125 can be placed in the trocar. Each actuating unit can be arranged to cause movement in all four degrees of freedom 111 to 114.

[0047] The surgical robot system may further include a user interface for receiving user input such as positioning commands from a human operator, such as a surgeon or healthcare provider. In some embodiments, the user interface may include or be constituted by a motion controller such as a joystick. In some embodiments, the motion controller may be an external device configured such that the user interface or the processor subsystem 040 interfaces therewith. In some embodiments, the motion controller may be included in the surgical robot system as a further component configured to interface with, for example, the processor subsystem 040 and / or the user interface 020. FIG. 4 shows a joint diagram showing the motion characteristics of such a motion controller. Here, the motion controller has DoFs Φ m 115, Ψ m 116, Ζ m 117 and Θ mIt is shown to have 118. The user may provide user inputs such as positioning commands, for example, by gripping the gripper part of the motion controller, pressing button 126, and moving the gripper part of the motion controller in 3D space.

[0048] FIG. 5 shows a surgical instrument 119 within an eye 200 according to an embodiment of the present invention. The tip 122 of the surgical instrument 119 is also shown enlarged.

[0049] As shown on the left - hand side of FIG. 5, the surgical instrument 119 is shown in a state of being inserted into the eye 200. As shown in this figure, the surgical instrument 119 can approach the retina 210, but this is merely an illustration and the present invention is not limited thereto. In some embodiments, the surgical instrument 119 can approach another region, structure, or tissue layer of the eye.

[0050] The tip 122 of the surgical instrument 119 is shown enlarged on the right hand side of FIG. 5. In this example, the surgical target 123 is located on the retina. The surgical instrument may be an irrigation / suction instrument for irrigating or aspirating fluid at a desired target location, a photocoagulation instrument for applying light energy at a desired distance from the target, a vitrectomy instrument for excising and aspirating vitreous humor or other fluid at a desired distance from the target, a tissue manipulation instrument that needs to be accurately positioned at a first interface of the tissue, or the like. The tip 122 of the surgical instrument 119 may be an injection lumen. A sensor or sensor component 121 such as an optical fiber may be incorporated into or attached to the surgical instrument 119. In some embodiments, the sensor 030 may include an optical fiber (such as shown) configured to acquire sensor data 032 indicating the distance D between the surface of the retina 210 and the tip 122 of the surgical instrument 119. The optical fiber 121 may be recessed from the tip 122 of the surgical instrument 119. In some embodiments, the sensor 030 may be configured to determine the distance between the end of the optical fiber 121 and the surface of the retina 210, and then subtract an offset corresponding to the distance by which the optical fiber 121 is recessed from the tip 122 of the surgical instrument 119 to obtain the distance D. In some embodiments, the distance D may be determined using a light beam 127. Since the optical fiber 121 is recessed from the tip 122 of the surgical instrument 119, it is possible and advantageous to acquire sensor data while the tip 122 of the surgical instrument 119 is perforating or penetrating the tissue layer.

[0051] The distance between the tip 122 of the surgical instrument 119 and the surgical target 123 may be determined using the distance D between the surface of the retina 210 and the tip 122 of the surgical instrument 119. For example, the surgical target 123 may be a layer of the retina 210 or its surface at a known depth, and the distance between the tip of the surgical instrument and the surgical target 123 may be determined by adding the known depth of the surgical target 123 to the distance D between the tip 122 of the surgical instrument 119 and the surface of the retina 210.

[0052] In some embodiments, the target location may correspond to the surface of the retina 210. More generally, the target location may be determined based on the location or detection of a structure or tissue layer, such as the surface of the retina 210.

[0053] In the foregoing examples, primarily the distance between the tip 122 of the surgical instrument 119 and, for example, the surface of the retina 210 has been referred to. However, it should be understood that the present invention is not limited thereto. In some embodiments, the distance may be measured from another part of the surgical instrument 119 instead of or in addition to the tip 122. For example, the distance may be determined with respect to the position of an optical fiber, a marker on the surgical instrument 119, and the like.

[0054] FIG. 6A shows a surgical instrument 119 in an initial position within the eye 200 according to one embodiment of the present invention. Similar to FIG. 5, a surgical instrument 119 approaching a point along the surface of the retina 210 is shown. It is reiterated here that the selection of this surgical target is merely illustrative. The methods and systems disclosed herein are equally applicable regardless of the selection of the surgical target. In FIG. 6A, the surgical instrument 119 is shown at an initial position at a distance D(initial) from the surgical target 123. While in the initial position, the distance D(initial) may be determined, for example, using a sensor 030 coupled to, attached to, or incorporated into the surgical instrument 119, as shown in FIG. 5. Preferably, the sensor measurement is taken while the surgical instrument 119 is stationary. When the distance between the surgical instrument 119, e.g., the tip 122 of the surgical instrument 119 and the surgical target 123, is known, the displacement distance may be determined. The displacement distance is a distance configured for the surgical instrument 119 to move and may be defined as the distance between the surgical instrument 119 and the target position. The displacement distance may be the (e.g., total) distance to the surgical target 123, or the displacement distance may be shorter than the distance to the surgical target 123. For example, when the surgical target 123 is located in a particularly complex and / or delicate part of the eye 200, or when it is difficult to read the position of the surgical target 123 using a sensor, it may be advantageous to first move the surgical instrument 119 by a first distance to a next position where more reliable sensor data can be obtained. Selecting a displacement distance shorter than the initial distance between the surgical instrument 119 and the surgical target 123 may be further advantageous when there is a high likelihood of movement of the eye 200 or the patient during movement of the instrument, e.g., when the structures within the eye 200 and / or the surgical target 123 are likely to move as a result of the movement of the surgical instrument.

[0055] The displacement distance may be determined by obtaining a user input indicating the target position of the surgical instrument, such as, for example, on a graphical user interface, an input specifying the target depth or even indicating a specific target position. In some embodiments, the target position may correspond to the surgical target, and the user may simply indicate that the target position is the position of the surgical target. In some embodiments, the displacement distance may be determined using a predetermined setting, such as a defined offset from the surgical target. Such an offset may be, for example, 2 mm in front of the surgical target. In some embodiments, the displacement distance may be automatically determined, for example, based on the detection of one or more anatomical structures, tissue layers, etc., or based on the noise in the sensor data. For example, if there is a lot of noise in the sensor data, a shorter displacement distance may be determined. In some embodiments, the displacement distance may be automatically determined, for example, based on the initial distance, for example, to cover a predetermined portion of the initial distance.

[0056] When the displacement distance is determined, the surgical robot system 100 may be configured to output a perceptible indication of the determined displacement distance. The user is required to confirm the determined displacement distance before being able to move the surgical instrument 119. By requiring the user to confirm the determined displacement distance, it is possible for the user to ensure that the value determined by the system 100 is reasonable. That is, since an inaccurate or noisy displacement distance may be calculated due to inaccurate or noisy sensor data or detection, the risk associated with movement of the surgical instrument over an inappropriate (e.g., too far or unnecessarily short) distance may be reduced. This step also involves the user directly in the movement of the surgical instrument 119 and removes some of the discomfort typically associated with automation in this field without causing risks associated with hand tremors, vibrations, etc.

[0057] User confirmation is provided, for example, by clicking a button on a mouse or motion controller, pressing a foot pedal, providing an oral confirmation response using a microphone and speech recognition, gesture recognition of a gesture captured using a camera configured for gesture capture, or any combination thereof, within a graphical user interface or the like. Some or all of these user interaction means may be incorporated into the user interface or used via the user interface.

[0058] Upon acquisition of the user confirmation signal, the surgical instrument 119 may be moved by the determined displacement distance in a single movement. That is, the movement of the surgical instrument 119 over the determined displacement distance may be without pause or interruption. FIG. 6B shows the new position of the surgical instrument 119. In some embodiments, the movement of the surgical instrument 119 over the determined displacement distance may be performed at a constant speed or a constant acceleration, or the speed or acceleration of the surgical instrument 119 may be non-linear.

[0059] In some embodiments, aspects of the movement of the surgical instrument 119, such as speed, acceleration, etc., may be adapted based on a certainty score. The certainty score may represent the certainty of a determined distance between the surgical instrument and the surgical target and / or the certainty of the acquired sensor data 032. The certainty score may also be a confidence score representing the confidence level of the determined distance and / or the sensor data 032, or may be referred to as a reliability score indicating the reliability of the measurement or calculation of, for example, the determined distance or the acquired sensor data. In other words, the certainty score is a quantifiable measure of the accuracy and reliability of the measurement. That is, the certainty score may represent the certainty of the initial distance between the surgical instrument 119 and the surgical target (e.g., before moving the surgical instrument 119), or the certainty of the determined displacement distance between the surgical instrument 119 and the target position (e.g., before moving the surgical instrument 119). For example, the certainty score may be low due to measurement noise, measurement artifacts, and / or the sensor being at least partially blocked, for example, by debris in the eye. The certainty score may be calculated based on at least one of noise associated with the acquired sensor data, movement of the surgical target, comparison of the sensor data with a reference model, and comparison of the estimated surgical target position with the predicted position of the surgical target.

[0060] The predicted surgical target position may be based on the movement of the instrument within the robot coordinates measured by at least one robot position sensor. In some embodiments, the robot 080 may include a suitable position sensor and may be used to determine the movement of the instrument.

[0061] Any known statistical method for determining certainty may be used in calculating the certainty score based on one or more of the above considerations. It may also be the output of a template matching algorithm, a Kalman filter, a Bayesian filter, and / or a machine learning algorithm.

[0062] When the certainty score is high, the surgical instrument 119 may be controlled, for example, to move at a faster speed than when the certainty score is low. Moreover, when an initial certainty score is calculated, the target position may be determined, at least in part, based on the certainty score. For example, when the initial certainty score is low, e.g., below a threshold value, the displacement distance may be shorter than when the initial certainty score is high (e.g., above the threshold value). The certainty score may also be used to select a control mode, as will be further clarified with reference to FIG. 6B.

[0063] In some embodiments, the certainty score may be calculated prior to a single movement of the surgical instrument 119. That is, prior to the user providing a confirmation signal, not only a perceptible display of the determined displacement distance but also a perceptible display of the certainty score may be output to the user. Thus, the user may or may not confirm the determined displacement distance while also considering the associated certainty score. In some embodiments, the determined displacement may be limited as a result of the certainty score. For example, when the certainty score is low, e.g., below a threshold value, the determined displacement distance may be shortened to prevent the surgical instrument 119 from reaching potentially dangerous or uncertain regions.

[0064] FIG. 6B shows the surgical instrument after a single movement of the surgical instrument 119, according to an embodiment of the present invention.

[0065] In some embodiments, the target position may be offset, for example, due to movement of the intraocular fluid or structure during a single movement of the surgical instrument 119. In such cases, a correction procedure may be performed to correct the position of the surgical instrument 119. That is, the sensor 030 may be configured to obtain updated sensor data 030' indicating the distance between the surgical instrument 119 at the current position (e.g., the position of the surgical instrument 119 after a single movement) and the surgical target 123. Next, the processor subsystem 040 of the surgical robot system 100 may be configured to determine the remaining distance D(remaining) between the surgical instrument 119 and the surgical target 123.

[0066] Next, the processor subsystem 040 may be configured to determine whether the target position has been reached based on the determined remaining distance. If it is determined that the remaining distance between the surgical instrument 119 and the surgical target 123 is the same as or approximately the same as the distance between the target position and the surgical target, the processor subsystem 040 may determine that the target position has actually been reached. If the remaining distance does not match the distance between the target position and the surgical target, for example, if the remaining distance does not fall within a predetermined margin, the processor subsystem 040 may determine that the target position has not been reached. Not reaching the target position may include, for example, passing by the target position or not reaching the target position.

[0067] If the processor subsystem 040 determines that the target position has not been reached, it moves the surgical instrument to correct the depth of the surgical instrument. That is, the processor subsystem 040 may determine a correction distance from the target position based on the determined remaining distance to the surgical target. The correction distance may be the same as the determined remaining distance, for example, when the target position corresponds to the surgical target, but it may not be so. In some embodiments, the target position is closer to the surgical instrument 119 than the surgical target 123, and the remaining distance between the surgical instrument 119 and the surgical target 123 may not correspond to the correction distance. In such a case, the correction distance may be determined based on the remaining distance. For example, the target position may be a distance Y from the surgical target 123, and the remaining distance D(remaining) between the surgical target 123 and the surgical instrument 119 may be Y + Δz, for example, D(remaining)=Y + Δz, so the correction distance may be determined to be Δz. That is, the remaining distance may be regarded as the sum of the distance between the target position and the surgical target and the correction distance. When the target position has been passed, the correction distance is negative, indicating that the surgical instrument 119 should be retracted by a distance Δz. The correction process may be repeated as necessary until the target position is reached.

[0068] However, if the processor subsystem 040 determines that the target position has been reached, it can be determined that the surgical instrument 119 is correctly positioned at the target position.

[0069] The correction procedure may be performed in a control mode selected from a displacement-based control mode, a restricted closed-loop control mode, and a motion controller-based control mode. However, in some embodiments, the surgical robot system 100 may be configured using only one or two of these control modes. For example, in some embodiments, the system 100 may be configured to select only two of these three modes.

[0070] Displacement-based control mode The displacement-based control mode is similar to the level of automation and control provided during the initial movement of the surgical instrument 119. That is, a displacement distance is determined (e.g., based on data indicating a target position), and a perceptible display of the determined displacement distance is output to the user, and the user is required to confirm the determined displacement distance before the movement of the surgical instrument can be made. That is, in the displacement-based control mode, a displacement distance is determined, this distance is proposed to the user (typically a surgeon) and approved by the user (typically a surgeon), and then the movement is automatically executed.

[0071] When the displacement-based control mode is selected for a correction procedure, as described above, a correction distance (also referred to as a correction displacement distance) is determined. A perceptible display of the correction distance is output to the user, and a further confirmation signal indicating confirmation of the determined correction distance is received from the user. Upon receipt of the further confirmation signal from the user, the surgical instrument 119 is moved over the correction distance in a single (e.g., continuous) movement. That is, the actuator 060 may be controlled to actuate the movable arm portion 082 to effect a further single movement of the surgical instrument 119 along the longitudinal axis over the correction displacement distance.

[0072] Limited closed-loop control mode In the limited closed-loop control mode, the control of the actuator 060 is more automated and requires less user involvement than the control in the displacement-based control mode, as follows, that is, - A predetermined duration of using the limited closed-loop control mode, - A predetermined maximum correction displacement distance, - Requiring that the certainty score remains above a certainty score threshold during the correction, - Requiring continuous user input during the correction and stopping the movement of the surgical instrument when it is detected that the continuous user input has ended may be restricted by at least one of the following.

[0073] In the restricted closed-loop control mode, the movement of the surgical instrument 119 (e.g., the actuation of the actuator) is automatically determined based on, for example, the update of sensor data and the update of the determined distance between, for example, the surgical instrument 119 and the surgical target 123. In other words, during the movement of the surgical instrument 119, the sensor 030 may be configured to repeatedly acquire updated sensor data 032'' indicating the distance between the surgical instrument 119 and the surgical target 123.

[0074] When the restricted closed-loop control mode is time-limited, the automatic movement control of the surgical instrument 119 may be disabled after a preset time. When the restricted closed-loop control mode is displacement-limited, the automatic movement control of the surgical instrument 119 may be disabled when the surgical instrument 119 is displaced by a preset maximum correction displacement distance.

[0075] When the restricted closed-loop control mode depends on a certainty score, the processor 040 may be configured to repeatedly determine and update the certainty score as described above and compare the updated certainty score with a threshold certainty score, for example, when the updated sensor data 032'' is acquired. When the certainty score is below the threshold certainty score, for example, when it is determined that the updated sensor data 032'' is very uncertain, the automatic control provided during the restricted closed-loop control mode is disabled.

[0076] When the restricted closed-loop control mode requires continuous operation, the movement of the surgical instrument 119 may be automated until the user input is released while some user input is continuously detected. For example, the user may press a foot pedal to perform the restricted closed-loop control mode, and the movement of the surgical instrument 119 may be automatic until the user removes their foot from the foot pedal. In this example, a continuous user input of the foot pedal is described, but it will be recognized that this is merely illustrative. In some embodiments, the continuous operation may be provided by eye gaze detection, gesture capture, voice detection, or pressing a trigger or similar button on the controller. For example, if voice detection is considered a user input indicating continuous operation, the surgeon may be required to repeat a phrase at a predetermined frequency, such as once every 3 seconds or 5 seconds.

[0077] Control Modes of the Motion Controller Base The control mode of the motion controller base is the least automated of the three control modes described herein and requires the most user involvement. In the control mode of the motion controller base, the movement of the surgical instrument 119 (e.g., control of the actuator 060 that actuates the movable arm 082 to effect movement of the surgical instrument 119) is controlled by the user. The user may provide an input such as a positioning command via, for example, a motion controller or a joystick, or a similar input via the user interface 020. Although effects such as hand tremors or vibrations can be reduced or even eliminated using solutions known in the art, in the control mode of the motion controller base, the user may control the movement of the surgical instrument 119.

[0078] In some embodiments, the control mode used when correcting the position of the surgical instrument 119 may be selected by the user or may be selected based on the calculation of a certainty score. The latter will be described in more detail with reference to FIGS. 7A and 7B.

[0079] Returning now to FIGS. 6A and 6B, in some embodiments, the process may be repeated when it is determined that the target position has been reached. That is, sensor 030 may acquire updated sensor data 032b indicating the distance between surgical instrument 119 and the surgical target. System 100 may further acquire data indicating a next target position that is different from the initial target position. For example, the user may indicate the next target position via a graphical user interface. The sensor data 032b acquired with respect to surgical instrument 119 at this current position may be more reliable than the original sensor data 030, enabling the user to more safely select a target position closer to the surgical target or actually select the surgical target as the next target position. The updated displacement distance may then be determined based on the sensor data 032b and the next target position. Thereafter, a perceptible indication of the updated displacement distance may be output to the user, e.g., via a user interface. Examples of perceptible outputs have already been provided with reference to FIGS. 1 and 5 and are not repeated here for the sake of brevity. The user may again provide a further confirmation signal indicating confirmation of the updated displacement distance. Upon receipt of the further confirmation signal, surgical instrument 119 may be moved over the updated displacement distance in a single movement.

[0080] This process may be repeated as many times as necessary to reach the surgical target.

[0081] Throughout the above description, movement of the surgical instrument has been referred to. It should be understood that the surgical instrument 119 is moved by controlling the actuator 060 to activate the movable arm portion 082 that effects movement of the surgical instrument 119.

[0082] FIG. 7A schematically illustrates a method 700 for selecting a control mode according to an embodiment of the present invention. In an operation entitled "calculate a certainty score", the processor subsystem 040 may calculate a certainty score that may be associated with sensor data acquired by a sensor and / or a distance determined based on the sensor data (710). For example, when determining whether the surgical instrument 119 has reached the target position, the certainty score may be calculated at the time when the surgical instrument 119 is moved over the determined displacement distance.

[0083] Next, in an operation entitled "compare the certainty score with a first threshold" of the method 700, the processor subsystem 040 may compare the calculated certainty score with a first certainty score threshold (720). In some embodiments, the first certainty score threshold may be the only certainty score threshold. This is illustrated in FIG. 7A which is currently being described. However, in other embodiments, as will be apparent with reference to FIGS. 7B, 8A, and 8B, there may be multiple certainty score thresholds.

[0084] In block 730, if the calculated certainty score is not higher than the first certainty score threshold, for example, if it is determined that the measurement or distance associated with the certainty score is uncertain or not sufficiently reliable, the method 700 proceeds to operation 740 entitled "select a motion controller-based control mode". That is, if the calculated certainty score is not higher than the first certainty score threshold, the actuator may be controlled using the above-described motion controller-based control mode. Accordingly, the user gives a positioning command, reducing the degree of automation associated with the movement of the surgical instrument 119. This may be due to noisy sensor data such that the system 100 cannot detect the surgical target with sufficient certainty or confidence.

[0085] In block 730, if the processor subsystem 040 determines that the calculated certainty score exceeds or meets a first certainty score threshold, the method may proceed to operation 750, entitled "select displacement-based control mode", or operation 760, entitled "select restricted closed-loop control mode". In some embodiments, system 100, specifically the actuator, may be configured to be controlled using one of two control modes when correcting the position of surgical instrument 119. In some embodiments, actuator 060 may be controlled in either a motion controller-based control mode or a displacement-based control mode. In other words, if the calculated certainty score is below the first certainty score threshold, actuator 060 may be controlled in a motion controller-based control mode, and if the calculated certainty score is greater than or equal to the first certainty score threshold, actuator 060 may be controlled in a displacement-based control mode. In some embodiments, actuator 060 may be controlled in either a motion controller-based control mode or a restricted closed-loop control mode. That is, if the calculated certainty score is below the first certainty score threshold, actuator 060 may be controlled in a motion controller-based control mode, and if the calculated certainty score is greater than or equal to the first certainty score threshold, actuator 060 may be controlled in a restricted closed-loop control mode.

[0086] With reference to FIGS. 7B, 8A, and 8B, embodiments in which actuator 060 can be controlled in either a motion controller-based control mode, a displacement-based control mode, or a restricted closed-loop control mode will be described.

[0087] FIG. 7B schematically shows a variant 700’ of a method 700 for selecting a control mode using a certainty score according to an embodiment of the present invention. FIG. 7B differs from FIG. 7A in that a second certainty score threshold higher than the first certainty score threshold is used. Operations 710, 720, 730, and 740 are the same as those described with respect to FIG. 7A. For the sake of brevity, these operations will not be described again here, and only the differences between the method 700 of FIG. 7A and the variant 700’ of FIG. 7B will be described.

[0088] In block 730, if the processor subsystem 040 determines that the calculated certainty score exceeds the first certainty score threshold, method 700’ proceeds to operation 744 entitled “Compare the certainty score with a second threshold”. In operation 744, the calculated certainty score is compared with a second certainty score threshold that is higher than the first certainty score threshold.

[0089] In block 746, if the processor subsystem 040 determines that the calculated certainty score exceeds the second certainty score threshold, method 700’ may proceed to operation 760 entitled “Select a restricted closed-loop control mode” in which the actuator 060 can be controlled using the restricted closed-loop control mode described above.

[0090] In block 746, if the processor subsystem 040 determines that the calculated certainty score does not exceed the second certainty score threshold, method 700’ may proceed to operation 750 entitled “Select a displacement-based control mode” in which the actuator 060 can be controlled using the displacement-based control mode described above.

[0091] These certainty score thresholds may be used to adapt the degree of automation of the movement of the surgical instrument 119 based on the certainty associated with the sensor measurements and / or the determined distance. This is illustrated in FIG. 8A.

[0092] Referring now to FIG. 8A, when the calculated certainty score falls below a first certainty score threshold CSThr1, a motion controller-based control mode 810 may be selected. When the calculated certainty score exceeds the first certainty score threshold CSThr1 but is below a second certainty score threshold CSThr2, a displacement-based control mode 820 is selected. When the calculated certainty score exceeds the second certainty score threshold CSThr2, a restricted closed-loop control mode 830 is selected. As described above, the use of the second certainty score threshold is optional.

[0093] Although not shown, in some embodiments, the control mode for the actuator 060 may be selected from a displacement-based control mode and a restricted closed-loop control mode. In other words, the first threshold CSThr1, and similarly operations 720 and 730, may be optional.

[0094] In the foregoing description, a certainty score has been used to select a control mode. However, in some embodiments, the comparison of the certainty score with one or more thresholds, or alternatively, for example, by controlling the maximum displacement or movement speed of the surgical instrument 119, etc., may be used to control the actuator differently within the control mode. For example, the actuator may be operated in a restricted closed-loop control mode, but based on the calculated certainty score, the maximum displacement of the surgical instrument 119 may be used, and / or the speed of the surgical instrument 119 may be determined as a function of the certainty score. The function of the certainty score may be, for example, a step function (e.g., a first speed when the certainty score is below a first threshold, a second speed faster than the first speed when the certainty score exceeds the first threshold and is below a second threshold, which is optionally higher than the first threshold, and optionally, a third speed faster than the second speed when the certainty score exceeds the second threshold, etc.), or a continuous function.

[0095] The certainty score may be used in several ways throughout an ophthalmic surgical procedure. For this purpose, FIG. 8B illustrates, according to one embodiment of the invention, thresholds for selecting a control mode and / or for triggering an interruption procedure. Referring to FIG. 9, the interruption procedure itself will be described in more detail.

[0096] In addition to, or as an alternative to, one or more of the certainty score thresholds described with reference to FIGS. 7A, 7B, and 8A, a certainty score threshold may be used to trigger an interruption procedure. Such a certainty score threshold may be referred to as a certainty score limit threshold, an interruption threshold, or simply a certainty score threshold. Throughout the following description, the term “interruption threshold” is employed.

[0097] The interruption threshold AbThr may be used without a further certainty score threshold, such as the certainty score threshold described with reference to FIG. 8A. That is, in some embodiments, the only certainty score threshold used is the interruption threshold AbThr. However, in some embodiments, the interruption threshold AbThr may be used in conjunction with at least one further certainty score threshold CSThr1, CSThr2 for selecting a control mode.

[0098] During a correction procedure, when a certainty score is calculated, or in embodiments where a certainty score is calculated during movement of the surgical instrument 119, the calculated certainty score may be compared to the interruption threshold AbThr. The interruption threshold AbThr may be lower than the threshold CSThr1 used for selecting a control mode. If the calculated certainty score falls below the interruption threshold AbThr, an interruption procedure 840 may be triggered. In some embodiments, the motion controller-based control mode 810 may be selected when the calculated certainty score is between the interruption threshold AbThr and a first certainty score threshold CSThr1.

[0099] FIG. 9 schematically illustrates a method 900 for triggering an interruption procedure, according to one embodiment of the invention.

[0100] Method 900 may include calculating a certainty score 910 in an operation entitled "calculate a certainty score". The calculation of the certainty score may be performed during the movement of the surgical instrument 119 or before the movement of the surgical instrument 119, for example, when determining whether the surgical instrument 119 has reached a target position at any point during the ophthalmic surgical procedure. In some embodiments, the certainty score may be calculated each time sensor data or updated sensor data is acquired.

[0101] The method may further include comparing the calculated certainty score with a certainty score threshold, such as an interruption threshold AbThr, in an operation entitled "compare the certainty score with a threshold". In block 930, if it is determined that the certainty score meets or exceeds the certainty score threshold, the method may continue the movement of the surgical instrument 940a or continue the ophthalmic surgical procedure 940b. In some embodiments, method 900 may be repeated from operation 910, for example, when sensor data is repeatedly updated during the movement of the surgical instrument 119, such that a new certainty score may be calculated. Method 900 does not necessarily need to be repeated immediately.

[0102] If the certainty score is below the certainty score threshold, the method may proceed to operation 950, entitled "perform an interruption procedure".

[0103] Interruption procedure Interruption procedure 950 may include one or more of the following operations, namely, - Retracting the surgical instrument 119, - Temporarily stopping the movement of the surgical instrument 119, and - Switching the control of the actuator from the restricted closed-loop control mode to the motion controller-based control mode of the above.

[0104] In particular, the temporary stop of the movement of the surgical instrument 119 may be performed in combination with any of the other enumerated operations. In some embodiments, after temporarily stopping the movement of the surgical instrument 119, updated sensor data may be acquired. In some cases, more reliable sensor data may be acquired while the surgical instrument 119 is stationary. In such a case, if an improved certainty score is calculated as a result of the updated sensor data, it may be possible to resume the ophthalmic surgical procedure.

[0105] In some embodiments, the interruption procedure may include first temporarily stopping the movement of the surgical instrument 119, acquiring new sensor data, calculating a new certainty score, and comparing the new certainty score with a certainty score threshold. If the new certainty score still does not meet the certainty score threshold, the surgical instrument 119 may be retracted.

[0106] In some embodiments, the surgical instrument 119 may be retracted immediately after determining that the interruption procedure has been triggered.

[0107] In some embodiments, the surgical instrument 119 may be partially retracted, for example, retracted a short distance or fully retracted, in order to return the surgical instrument 119 to its original position.

[0108] In some embodiments, the control mode for controlling the actuator 060 may be switched when the certainty score falls below an interruption threshold AbThr. For example, if the actuator is controlled in a restricted closed-loop control mode and the certainty score falls below the interruption threshold AbThr, the control mode of the actuator 060 may be switched to either a displacement-based control mode or a motion controller-based control mode. If the actuator 060 is controlled in a displacement-based control mode and the certainty score falls below the interruption threshold AbThr, the control mode of the actuator 060 may be switched to a motion controller-based control mode.

[0109] Figure 10A shows a surgical target between two tissue layers before injection according to an embodiment of the present invention, Figure 10B also shows a depressed retina before injection according to an embodiment of the present invention, and Figure 10C shows a surgical target between two tissue layers during injection.

[0110] In some embodiments, the sensor 030 may be configured to obtain sensor data 032 indicating the distance between the surgical instrument 119 and the plurality of tissue layers. As shown in Figure 10A, a distance sensor 121, such as an optical fiber, may be attached to, incorporated in, or coupled to the surgical instrument 119 and may be a component of the sensor 030. That is, the sensor 030 may include the distance sensor 121. The sensor 030, for example the distance sensor 121, may be configured to determine a first distance D1 between the surgical instrument 119, for example the tip 122 of the surgical instrument 119, and a first tissue layer 220 in the eye, and a second distance D2 between the surgical instrument 119, for example the tip 122 of the surgical instrument 119, and a second tissue layer 230 in the eye. In Figure 10A, arrows indicating the distances D1 and D2 are shown at different angles, but this is merely for ease of explanation, and the distances between the surgical instrument 119 and each of the layers 220, 230 may be determined along the same axis.

[0111] In some embodiments, it can be found that the surgical target 123 is between two tissue layers 220, 230 of the eye, for example, by being an intermediate tissue layer. However, when the surgical instrument 119 contacts the first tissue layer 220 of the eye and is moved, for example, to push the first tissue layer 220, a depression may be formed in the retina 210, and the surgical target 123 may be displaced or deformed as shown in FIG. 10B. The pressure of the surgical instrument on the first layer 220 may cause a depression in the retina 210 as shown in FIG. 10B. In such a case, the determination of the first distance D1 between the surgical instrument 119 and the first tissue layer 220, as well as the determination of the second distance D2 between the surgical instrument 119 and the second tissue layer 230, may be used to improve the determination of the position of the surgical target 123. Although not shown in FIG. 7B, while the surgical instrument 119 is in contact with and / or pressing the tissue layer 220, the sensor 030, for example, the distance sensor 121, may be configured to acquire sensor data indicating the distance D1 between the surgical instrument 119 and the first tissue layer 220 and the distance D2 between the surgical instrument 119 and the second tissue layer 230.

[0112] In some embodiments, the system 100 may detect when the surgical instrument 119 reaches the first layer 220. For example, the target position may be determined to correspond to the first layer 220. When this position is reached, the actuator 060 may be controlled to retract the surgical instrument 119 by a distance x before advancing the surgical instrument 119, preferably at a higher speed, for example, by a distance 2x, in order to improve the puncture / displacement ratio and thereby reduce the depression in the retina. Thus, the resulting displacement of the surgical instrument 119 is a distance x from the starting position. That is, the penetration of the tissue layer may be performed by advancing the surgical instrument 119 at a higher speed, for example, with a high-speed puncture motion. The speed used in the high-speed puncture motion may be preset, or the maximum speed of the surgical instrument 119 may be used.

[0113] In some embodiments, as illustrated in FIG. 10C, a bleb 240 may be formed upon injection of fluid into the retina 210. During the injection, the position of the surgical instrument 119 may be corrected. That is, while the surgical instrument 119 is injecting fluid between these two layers 220 and 230, the center of the bleb 240 may be determined, for example, based on the determination of the distances between the surgical instrument 119 and each of the two layers 220 and 230. The surgical instrument 119 may be retracted or extended to the bleb center.

[0114] FIG. 11 schematically illustrates a method 1100 for controlling a surgical robot system during use in an ophthalmic surgical procedure. The surgical robot system includes a surgical arm, the surgical arm includes a movable arm portion, the movable arm portion includes an instrument connector for attachment of a surgical instrument having a longitudinal axis, the movable arm portion has at least one degree of freedom enabling longitudinal movement of the surgical instrument along the longitudinal axis of the surgical instrument towards or away from an ophthalmic surgical target, and the surgical robot system further includes an actuator configured and arranged to actuate the movable arm portion to effect longitudinal movement of the surgical instrument. Method 1100 includes, in an operation entitled "acquire sensor data", acquiring 1110 sensor data indicative of a distance between the surgical instrument and the surgical target when the surgical instrument is in an initial position. Method 1100 further includes, in an operation entitled "determine initial distance", determining 1120 an initial distance between the surgical instrument in the initial position and the surgical target based on the sensor data. Method 1100 further includes, in an operation entitled "acquire target position relative to surgical target", acquiring 1130 data indicative of a target position of the surgical instrument relative to the surgical target. Method 1100 further includes, in an operation entitled "determine displacement distance", determining 1140 a displacement distance for the surgical instrument based on the sensor data and the target position. Method 1100 further includes, in an operation entitled "output displacement distance", outputting 1150 to a user a perceptible indication of the displacement distance. Method 1100 further includes, in an operation entitled "receive user confirmation", receiving 1160 a confirmation signal from the user. Method 1100 further includes, in an operation entitled "actuate movable arm", controlling 1170 the actuator to actuate the movable arm portion to effect a single movement of the surgical instrument along the longitudinal axis over the displacement distance upon receipt of the confirmation signal. Note that the operations of method 1100 need not be performed strictly sequentially. For example, operations 1120 and 1130 may be performed in a different order or substantially simultaneously. Similarly, operations 1110 and 1120 may be performed in a different order or substantially simultaneously.

[0115] The method according to the present invention may be implemented on a processor as a computer-implemented method, or in dedicated hardware, or in a combination of both. Executable code for the method according to the present invention may be stored in a computer program product. Examples of computer program products include memory devices, optical storage devices, integrated circuits, servers, online software, and the like. FIG. 12 shows a computer program product in the form of a computer-readable medium 1260 including the program code for causing a processor to perform the method according to the present invention when the non-temporary program code 1250 is executed by the processor.

[0116] In a preferred embodiment, the computer program includes computer program code means adapted to perform all steps of the method according to the present invention when the computer program is executed by a processor. Preferably, the computer program is embodied on a computer-readable medium.

[0117] Throughout the above description, various distances between the surgical instrument and the target position, surgical target, tissue layer, etc. are referred to. These distances may each correspond to the distance between the tip of the surgical instrument and the target position, surgical target, tissue layer, etc. That is, the distances described throughout this description may, according to some embodiments, be obtained from the tip of the surgical instrument.

[0118] It should be noted that the above-described embodiments are illustrative rather than limiting the present invention, and those skilled in the art can design many alternative embodiments.

[0119] In a claim or clause, any reference signs placed in parentheses shall not be construed as limiting the claim or clause. The use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those recited in the claim or clause. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware including several distinct elements, and also by means of a computer suitably programmed. In an apparatus claim or clause listing several means, several of these means may be embodied by the same hardware device. The mere fact that certain measures are recited in mutually different dependent claims or clauses does not indicate that a combination of these measures cannot be used advantageously.

Claims

1. A surgical robot system (100) for use in ophthalmic surgery, comprising: - A surgical arm (080) including a movable arm portion (082), the movable arm portion (082) including an instrument connector for attaching a surgical instrument (119) having a longitudinal axis, the movable arm portion (082) being configured to move the surgical instrument (119) along the longitudinal axis of the surgical instrument (119) towards or away from an ophthalmic surgical target (123), the surgical arm (080) having at least one degree of freedom enabling longitudinal movement of the surgical instrument (119); - A sensor (030) configured to acquire sensor data (032) indicative of a distance between the surgical instrument (119) and the surgical target (123); - A user interface (020) configured to receive user input from a user and output an output perceptible to the user; - An actuator (060) configured and arranged to actuate the movable arm portion (082) to cause longitudinal movement of the surgical instrument (119); - A processor subsystem (040), - At an initial position of the surgical instrument (119), acquiring sensor data (032) from the sensor (030) and determining an initial distance between the surgical instrument (119) and the surgical target (123) based on the sensor data (032); - Acquiring data indicative of a target position of the surgical instrument (119) relative to the surgical target (123); - Determining a displacement distance of the surgical instrument (119) advancing towards the surgical target (123) based on the sensor data (032) and the target position; - Outputting a perceptible representation of the determined displacement distance via the user interface (020); - Requesting confirmation of the determined displacement distance from the user via the user interface (020); - Receiving a confirmation signal indicative of confirmation of the determined displacement distance from the user via the user interface (020); - Controlling the actuator (060) to actuate the movable arm portion (082) to cause a single movement of the surgical instrument (119) along the longitudinal axis over the determined displacement distance upon receiving the confirmation signal A processor subsystem (040) configured as such, A surgical robot system (100) including

2. The processor subsystem (040) further - When the single movement of the surgical instrument (119) is completed, obtain the latest sensor data (032') from the sensor (030), and based on the latest sensor data (032'), determine the remaining distance between the surgical instrument (119) and the surgical target (123), - Based on the determined remaining distance, determine whether the target position has been reached, - If not reached, control the actuator (060) to correct the target position of the surgical instrument (119) based on the determined remaining distance The surgical robot system (100) according to claim 1, configured as such.

3. The processor subsystem (040) - Determine a correction displacement distance for reaching the target position from the determined remaining distance to the surgical target (123), - Output a perceptible representation of the correction displacement distance via the user interface (020), - Request confirmation of the determined correction displacement distance from the user via the user interface (020), - Receive a further confirmation signal indicating confirmation of the determined correction displacement distance from the user via the user interface (020), - When receiving the further confirmation signal, control the actuator (060) to operate the movable arm portion (082) to cause a further single movement of the surgical instrument (119) along the longitudinal axis over the correction displacement distance Thereby, the actuator (060) is configured to control the target position of the surgical instrument (119) in a displacement-based control mode, as described in claim 2 of the surgical robot system (100).

4. The processor subsystem (040) is configured to control the actuator (060) in a restricted closed-loop control mode to correct the target position of the surgical instrument (119) using the latest sensor data (032). The automatic movement control of the surgical instrument (119) in the restricted closed-loop control mode - After the preset usage time of the restricted closed-loop control mode has elapsed, - When a certainty score representing the certainty of the determined remaining distance falls below a certainty score threshold - When the user input is released The surgical robot system (100) according to claim 2, which is invalidated when at least one of the conditions is satisfied.

5. The processor subsystem (040) further - Calculates a certainty score representing the certainty of the determined distance between the surgical instrument (119) and the surgical target (123), - Changes the mode of control of the actuator (060) according to the calculated certainty score The surgical robot system (100) according to any one of claims 2 to 4, which is configured to be like this.

6. The processor subsystem (040) is further configured to calculate the certainty score based on at least one of an estimated value of the measurement noise of the sensor (032) and detection of movement of the surgical target (123). The surgical robot system (100) according to claim 5.

7. The processor subsystem (040) repeatedly calculates the certainty score and is configured to execute an interruption procedure when the calculated certainty score falls below a certainty score threshold. The interruption procedure is - Retracting the surgical instrument (119), - Temporarily stopping the movement of the surgical instrument (119), and - Switching the actuator (060) from being controlled in the restricted closed-loop control mode to being controlled in the motion controller-based control mode, including at least one of The processor subsystem (040) is configured to control the actuator (060) according to a position control command received from the user via a motion controller. The surgical robot system (100) according to claim 5, which is dependent on claim 4.

8. The processor subsystem (040) is further configured to select a control mode from a series of control modes based on the calculated certainty score. The series of control modes includes at least two of a motion controller-based control mode, a displacement-based control mode, and a restricted closed-loop control mode. ​ - In the motion controller-based control mode, the processor subsystem (040) is configured to control the actuator (060) according to the position control command received from the user via the motion controller of the user interface (020). - In the displacement-based control mode, the processor subsystem (040) - determines a correction displacement distance to reach the target position from the determined remaining distance to the surgical target (123), - outputs a perceptible representation of the correction displacement distance via the user interface (020), - requests confirmation of the determined correction displacement distance from the user via the user interface (020), - receives a further confirmation signal indicating confirmation of the determined correction displacement distance from the user via the user interface (020), - controls the actuator (060) to activate the movable arm portion (082) to cause a further single movement of the surgical instrument (119) along the longitudinal axis over the correction displacement distance when the further confirmation signal is received is configured as such, - In the restricted closed-loop control mode, the processor subsystem (040) - after the preset usage time of the restricted closed-loop control mode has elapsed, - when the certainty score representing the certainty of the determined remaining distance falls below a certainty score threshold, - when user input is released, is configured to disable the automatic movement control of the surgical instrument (119) when at least one of the conditions is met. The surgical robot system (100) according to claim 5.

9. The processor subsystem (040) is further configured to output a perceptible representation of the calculated certainty score via the user interface (020) before receiving the confirmation signal from the user. The surgical robot system (100) according to claim 5.

10. The sensor (030) - an optical coherence tomography (OCT) sensor configured to be optically coupled to an optical fiber attached to or incorporated in the surgical instrument (119), - an intraoperative optical coherence tomograph (iOCT) via a microscope, - a stereo camera via a microscope - An interferometer sensor incorporated in or attached to the surgical instrument (119), - A time-of-flight sensor incorporated in or attached to the surgical instrument (119), and - An ultrasonic sensor incorporated in or attached to the surgical instrument (119) The surgical robot system (100) according to any one of claims 1 to 4, comprising at least one of the above.

11. The processor subsystem (040) further - Obtains sensor data (032) indicating the distance between a first layer (220) of eye tissue and a second layer (230) of eye tissue, and the surgical target (123) is between the first layer (220) and the second layer (230), - Corrects the position of the surgical instrument (119) such that the surgical instrument (119) is between the first layer (220) and the second layer (230) The surgical robot system (100) according to any one of claims 1 to 4, configured as such.

12. The processor subsystem (040) is further configured to obtain sensor data (032) indicating the distance between a first layer (220) of eye tissue and a second layer (230) of eye tissue, and the surgical target (123) is between the first layer (220) and the second layer (230), The data indicating the target position of the surgical instrument (119) relative to the surgical target (123) includes data indicating the distance between the first layer (220) and the second layer (230). The surgical robot system (100) according to any one of claims 1 to 4.

13. A computer program (1250) comprising instructions for causing a processor system to execute a computer-implemented method (1100) for controlling a surgical robot system (100) during use in an ophthalmic surgical procedure, wherein the surgical robot system (100) comprises a surgical arm (080), the surgical arm (080) comprising a movable arm portion (082), the movable arm portion (082) comprising an instrument connector for attaching a surgical instrument (119) having a longitudinal axis, the movable arm portion (082) having at least one degree of freedom enabling longitudinal movement of the surgical instrument (119) along the longitudinal axis of the surgical instrument (119) towards or away from an ophthalmic surgical target (123), the surgical robot system (100) further comprising an actuator (060) configured and arranged to actuate the movable arm portion (082) to cause longitudinal movement of the surgical instrument (119), the method comprising: - obtaining (1110) sensor data (032) indicative of a distance between the surgical instrument (119) and the surgical target (123) at an initial position of the surgical instrument; - determining (1120) an initial distance between the surgical instrument (119) at the initial position and the surgical target (123) based on the sensor data (032); - obtaining (1130) data indicative of a target position of the surgical instrument (119) relative to the surgical target (123); - determining (1140) a displacement distance of the surgical instrument (119) advancing towards the surgical target (123) based on the sensor data (032) and the target position; - outputting (1150) a perceptible representation of the displacement distance to a user; - requesting confirmation of the determined displacement distance from the user; - receiving (1160) a confirmation signal from the user indicative of confirmation of the determined displacement distance; - controlling (1170) the actuator (060) to actuate the movable arm portion (082) to cause a single movement of the surgical instrument (119) along the longitudinal axis over the displacement distance upon receiving the confirmation signal; A computer program (1250) comprising the above. A computer-readable storage medium (1260) storing the computer program (1250) according to claim 13, as recited in claim 14.

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