Piloting a surgical device for eye surgery

Abstract

The invention relates to a surgical device (10) comprising at least two robots (11, 12), each robot (11, 12) comprising an articulated arm (21, 22) mounted on a base (31, 32), a tool (41, 42) being fixed to the end (E1, E2) of the arm (21, 22), each tool comprising a distal end (I1, I2) adapted to be inserted into an insertion point (T1, T2) of an eye, the device comprising a control unit (7) configured to move the end (E1, E2) of the arm of each robot so as to rotate the eye in its orbit to improve visibility and accessibility of the eye during surgery. Abstract figure: FIGURE 1a

Description

Title of the invention: Control of a surgical device for eye surgery Technical field

[0001] The present application relates generally to surgical devices, in particular those using a remotely manipulable surgical robot, and finds application in eye surgery. STATE OF THE ART

[0002] Eye surgery is a delicate procedure. In particular, vitreoretinal surgery is a surgical procedure that aims to remove the vitreous humor (the transparent gel that fills the eye) and to treat conditions that the retina may have, such as diabetic retinopathy, retinal detachments or even age-related macular degeneration.

[0003] This surgery is performed under local or general anesthesia, and is done via cannulas called trocars that are inserted into the sclera. Trocars allow surgeons to reach inside the eye with surgical tools (vitreotome, diathermy probe, laser, forceps, etc.) to remove the vitreous humor and treat underlying conditions. To perform this procedure, the surgeon sits at the head of the patient who is lying down, and to visualize what is happening, he uses an ophthalmic microscope.

[0004] Vitreoretinal surgery requires extremely stable and precise operating procedures, at the limit of the motor capacities and dexterity of surgeons.

[0005] To overcome these limitations, surgeons use robotic assistance, which makes it possible to perform this type of procedure with greater stability and precision, for an improved surgical result and increased patient safety. In particular, a device as described in document WO 2020 / 115249 is used. Such a device comprises a control station from which a surgeon remotely controls at least two surgical tools, each carried by a robotic arm.

[0006] Although presenting numerous advantages, such a device presents limited accessibility of the entire eyeball. Statement of the invention

[0007] The invention proposes to overcome at least one of these drawbacks. To this end, the invention proposes, according to a first aspect, a surgical device comprising at least two robots, each robot comprising an articulated arm mounted on a base, a tool being fixed to the end of the arm, each tool comprising a distal end adapted to be inserted into an insertion point of an eye, the device comprising a control unit configured to move the end of the arm of each robot, the control unit being configured to implement the following steps for each robot:

[0008] a) Receiving a position instruction for the end of the tool expressed in a reference frame linked to the insertion point, the tool being inserted into the eyeball of the eye, the eyeball being anatomically mobile in rotation relative to its orbit which is fixed relative to the base of the robots;

[0009] b) Receiving an instruction for orienting the eyeball in the orbit;

[0010] c) Configuration of a model of a geometric scene defined by each robot and the eye, the geometric model making it possible to locate any point in a reference frame associated with an element of the scene, said configuration taking into account the position instructions received and the orientation instruction received;

[0011] d) calculation from the configured model of the transformation of each robot defining the position and orientation of the end of each arm positioning the tools so as to obtain a globe oriented according to the orientation instruction received and placing the end of the tools according to the position instructions received;

[0012] e) piloting each robot to position each arm according to the calculated transformation.

[0013] The invention is advantageously supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0014] - the control unit is configured to implement a repetition of the steps a) to c) to continuously position each arm according to the positions and orientation received in steps a) and b).

[0015] - the geometric model of the scene is defined for each robot by

[0016] a first known transformation between a reference point linked to the point of insertion of the tool in the eye and a reference point linked to the center of the eyeball;

[0017] a second transformation defined solely by a rotation between a reference frame linked to the center of the eyeball and a fixed reference frame linked to the center of the orbit, said rotation corresponding to the received orientation;

[0018] a third known transformation between the reference frame linked to the center of the orbit and a fixed reference frame linked to the base;

[0019] a transformation of a robot between a reference frame linked to the end of the arm and the reference frame linked to the base, said transformation defining the position of the end of the arm in the reference frame linked to the base;

[0020] a fourth known transformation between the reference frame linked to the end of the arm and the reference frame linked to the end of the tool.

[0021] - step d) comprises the following sub-steps for each robot:

[0022] dl) determining the coordinates of a vector between the insertion point and the end of the tool in the frame linked to the end of the arm from the position of the insertion point in the frame linked to the end of the arm obtained from the received position and the fourth known transformation

[0023] d2) determination of the coordinates of the vector between the insertion point and the end of the tool in the coordinate system linked to the base from the position of the insertion point in the coordinate system linked to the base obtained from the second and third transformations and the received position

[0024] d3) calculation of the transformation of the robot from the coordinates of the vector obtained in steps dl) and d2).

[0025] - the position of the insertion point in the reference frame linked to the end of the tool depends on the position of the tool end in the coordinate system linked to the insertion point, with the arm end, tool end, and insertion point aligned.

[0026] - the marks linked to the end of the tool and to the end of the arm are oriented from the same way, the fourth transformation being a single translation along the axis of the tool.

[0027] - the control unit is configured to implement a determination of the position of the center of the eye in the coordinate system linked to the tool insertion point.

[0028] - the position of the center of the eye in the reference frame linked to the insertion point of the tool is determined by means of an eye model defined by

[0029] - an axial length AL which is the distance between the top of the cornea and the fovea

[0030] - an anterior chamber depth ACD distance between the apex of the cornea and the top of the lens

[0031] - a white-to-white distance WW: horizontal diameter of the cornea

[0032] - a limb-trocar distance LT; this is the distance separating the limb, that is to say the edge of the iris, from the trocar insertion point, measured radially to the iris

[0033] - the opening angle of the trocar a: this is the angle formed by the line OT and the axis longitudinal of the patient from feet to head, projected onto the plane (xOy) of the R”611 reference, model in which

[0034] - the radius of the eyeball R is R — — 1 ( AL-ACD )

[0035] - the limbus belongs to the surface of the eyeball, its distance from O is equal to R;

[0036] - the two reference points of the distance LT and the vertical axis z are coplanar

[0037] the position of the point O in the reference frames linked to the eye noted R^eiil and Rq6'12 being given by : x = -RsinOsina y = RsinOcosa z = RcosO x = RsinOsina y = RsinOcosa z = RcosQ Roeil2 0

[0039]

[0040]

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[0045]

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[0047]

[0048] with 9=2 sin 1 ((^r) )') + sin 1 () ] - the device comprises an imaging system configured to acquire at least one image of the eye, a control system being configured to specify a movement of the eye in combination with the acquired image of the eye and thus define a desired position of the eyeball to define the orientation of the eyeball in its orbit. - the control system includes a touch control screen or a trackball to define the desired eye rotation. The invention relates according to a second aspect to a computer-implemented method of controlling a surgical device according to the first aspect of the invention. The invention makes it possible to control a robot comprising two arms in order to obtain rotation of the eye during robotic eye surgery, using the synchronization of the movement of at least two surgical tools mounted on robotic mobile arms and passing through trocars. Thus, during robotic vitreoretinal surgery, it becomes possible to apply lateral force to the trocars by leveraging the tools. This allows the eyeball to rotate in its orbit and, consequently, to visualize the peripheral areas of the retina and to access them more easily. The invention allows the robotic arms to be positioned so that the ends of the tools are each at a desired position in the eye while ensuring that the eyeball is positioned in its orbit in a desired orientation. PRESENTATION OF FIGURES Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which: - [Fig. 1a] illustrates a surgical scene comprising a surgical device according to an embodiment of the invention - [Fig.lb] illustrates a geometric model corresponding to the surgical scene of [Fig.la]; - [Fig.2] illustrates geometric parameters of the eye used to estimate a position of the center of the eye;

[0050] - [Fig.3] illustrates steps for piloting the surgical device according to the invention implemented by a control unit of a surgical device according to the invention;

[0051] - [Fig.4] illustrates steps implemented by the control unit of a surgical device according to the invention;

[0052] - [Fig.5] illustrates the muscular structure of an eye;

[0053] - [Fig.6] illustrates a tactile display for specifying eye rotation;

[0054] - [Fig.7] illustrates a trackball type controller (in English, “track ball ”) to specify an eye rotation;

[0055] - [Fig.8] illustrates an interactor allowing to specify a rotation of the eye;

[0056] - [Fig.9] illustrates images of a retina to specify a rotation of the eye.

[0057] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION

[0058] Presentation

[0059] A method for controlling a surgical device to modify an orientation of the eye will be described. Such a method is based on a geometric model of the operating scene during robotic bimanual vitreoretinal surgery. We first describe the surgical device, then the construction of the scene and its use for geometry calculations. We will then assign input and output parameters to it. Finally, we will describe how the assembly can be used to position the surgical tools while generating a rotation of the eye during the control process. Finally, different means for defining a rotation of the eye will be described.

[0060] Device

[0061] [Fig. 1a] illustrates an operating scene So in which a surgical device 10 for eye surgery is used. Such a device comprises two robots 1, 2. Each robot comprises a robotic arm 21, 22 mounted on a base 31, 32 (here the base is mobile but this is not necessarily always the case). A tool 41, 42 is mounted at the end E1, E2 of each arm 21, 22. The tools 41, 42 are inserted into the operated eye 5 via a trocar T1, T2 (or insertion point). The tool 41, 42 is rectilinear and is modeled as an axis 411, 421 which extends from the end E1, E2 of each arm 21, 22 towards a free end of the axis, free end inserted into the trocar and which corresponds to the effector of the instrument (clamp, laser, etc.).

[0062] A control station 6 allows the surgeon to control the positioning of the tools 41, 42. Such a control station 6 is for example described in document WO 2022 / 106457 AL. In addition, a control unit 7 makes it possible to translate the surgeon's commands into instructions for controlling each arm. 21, 22 robotic so that the end E1, E2 of each arm 21, 22 moves according to the instructions from the control station 6. Also, an imaging system 8 allows the surgeon from the control station 6 to view the eye and the manipulated tools. Such an imaging system is for example an ophthalmic microscope.

[0063] Each robotic arm 21, 22 is equipped with actuators making it possible to move the tool 41, 42 in space according to at least six degrees of freedom (three translation axes and three rotation axes) in order to comply with the positioning commands from the control station 6.

[0064] Such an actuator architecture for a robotic arm 21, 22, allocating six degrees of freedom to the tool 41, 42 mounted thereon, makes it possible in particular to move it in such a way that its axis constantly passes through its Instantaneous Center of Rotation (ICR). The position of this center not being mechanically imposed, it can: • be defined by software at the exact location of the trocar T1, T2 through which the tool 41, 42 passes, so that its movements do not create constraints on the sclera of the eye 5; • be moved during surgery, for example to follow the patient's movements as described in document WO 2022 / 106457A1.

[0065] In order to allow better visibility of the eye during surgery, a control method which will be described will make it possible to determine a movement of the arms to allow rotation of the eye during surgery. In what follows, the method is described with the use of two surgical tools, and therefore two robotic arms, but it can be applied to a larger number without in any way modifying its principle. Model of the operating scene

[0066] The control of the surgical device 10 is based on a geometric model of the operating scene So defined by the eye and the robots 1, 2 of [Fig. 1a] whose geometric model Mso is illustrated in [Fig. 1b]. The operating scene So comprises several elements: • the two tools 41, 42 used for surgery; • the two robots 1, 2, each consisting of: • a robotic arm 21, 22 on which the tool 41, 42 is mounted; • the base 31, 32 possibly mobile in order to move the robot in the operating room but which remains fixed during surgery.

[0067] An eye 5 comprising an eyeball 51, for which two points 52, 53 for insertion of a tool 41, 42 are defined, the eyeball 51 and therefore the insertion points 52, 53 being mobile in an orbit 54. In this scene, the eyeball 51 is mobile in the orbit 54 which is fixed relative to the base 31, 32. Furthermore, the eye 5 has a center O which is both that of the orbit 54 and that of the eyeball 51.

[0068]

[0069]

[0070]

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[0073] Its position relative to base 31, 32 is known and determined during an initialization phase (we will come back to this). Each of the elements of the scene is assimilated to a body which transforms a spatial geometric reference frame R{t)orps into another reference frame R'j'°'l's. Each reference frame has an origin Oœ'ps and a direct orthonormal vector basis xcofps vcoFps zcofps j. For a given body, a single transformation of the space Tcoips allows to transform its reference frame RQOrps into its reference frame R}Orp\ Such a transformation consists of a translation which moves the origin of RqO1ps onto the origin of R]Orps and a rotation Qcorps which applied to R)jJrps changes its orientation into that of R“rps: ' rpcorps ^body / -. body x T. body ™body 1 T (R o )-Rj with T - ps . ù & -Body / „ body \ _ body tq 1 ( <J0 ) - Uj z-xCorps / coips coros „cofps ) _ / Ycofps coms Tcôrps ) ci iz (a0 , yQ , z0 j — (A} , . The transformation of a body is unique at each moment. It can either: • remain constant over time. This is the case for non-deformable solids, such as bases that are not moved during surgery, but also for tools whose flexibility is considered negligible in this model. • vary over time. This is particularly the case with robotic arms, the aim of which is to change the position and orientation of the tools in relation to the base. In relation to [Fig.lb], to constitute the model of the operating scene Mso, the bodies are assimilated to links of geometric chains SGI, SG2. Two mechanically linked bodies follow one another in a chain, and reference points are assigned to them so that the reference point Rq of one body coincides with the reference point Rj of the previous one. Taking into account two surgical tools held by two independent robotic mobile elements, as illustrated in [Fig.lb], the model is made up of two geometric chains SGI, SG2. These chains SG2, SG2, however, have a common link corresponding to the orbit 54 of the eye 5. It is thanks to this link that the movements of the two chains SGI, SG2 can be synchronized in order to generate a rotation of the eye. In [Fig.lb], the body chain models the operating scene So in a geometric manner by a geometric model Mso of the operating scene within the framework of the invention and makes it possible to move from one reference point of a body to another reference point of another body. According to this body chain, the links between each body within the scene are thus defined.

[0074] In the context of the invention we therefore have the following bodies: eye / insertion point 52, 53,; orbit 54, base 31, 32, robot 21, 22 and tool 41, 42 and as visible in figure 1 to a body are associated two references R^°'r's and RjOrps.

[0075] The table below lists the different bodies / elements of the scene as well as the associated markers.

[0076] In the reference column, the references R^aps and RjOlps are used without referring to the geometric chain considered, the two being identical. Chain 1 or 2 will be specified if necessary. It will be noted, in this respect, that the eye 5 comprises two bodies eye1 and eye2 each associated with an insertion point 52, 53 of a tool 41, 42 in the eye 5.

[0077] We note that for each chain similar markers are therefore defined. Body Description of the body Reference Reference description Eye This body corresponds to an insertion point 52, 53 in the patient's eyeball 51. It transforms the reference in which the tool positioning command is expressed into a reference centered in an insertion point 52, 53. The transformation of this body is known and fixed during surgery. tj eye R0 This reference is the one in which the tool position commands are expressed, as retrieved from the surgery n via the control station. Its origin Tb T2 corresponds to the center of the circle formed by the intersection of the trocar cannula with the sclera of the eye 5, surface of the eyeball. This is each insertion point 52, 53 of the tool in the eyeball 51. Its orientation is such that when no rotation has been applied to the eye, it is identical to that of the Rorblte - Rbase reference frame.T) eye K1 The positioning of this reference point is fixed relative to the reference point R'^ and their orientations are identical. Its origin O is in theory the center of the ball joint that exists between the eye and its orbit. The position of this origin is not measurable, but it is estimated during the process. Orbit This body corresponds to the orbit 52 in which the eyeball 51 is mobile. It allows the orientation of the eye 5 to be modeled, and is only made up of a rotation Qorblte which reorients the reference point R“e11 associated with the center of the eye 5 to obtain a rd orbit Ko r orbit This reference point is a fixed reference point in the operating room, the patient and the bed on which he is. fixed reference frame relative to the patient's head. The elongated t being considered as immobile. Its origin O is identical to that of the reference frame R”01' = R^rblte and corresponds to the center of the eye. Its orientation is such that its x axis is parallel to the transverse axis of the patient (from ear to ear) and its z axis is vertical. Base This body corresponds to the base which, if necessary, is mobile and allows the robots to be moved in the operating room. The transformation of this body is known and fixed during surgery. übase Ko This reference frame is the reference frame of the robot's base as defined by its control system, the one in which its Cartesian positions and instructions are expressed. For example, in the case of a serial robotic arm, the origin of this reference frame is generally located at the center of its first axis. This reference frame is also fixed in the operating room, the base being static during surgery.Its positioning relative to the reference frame - Rbase is considered known, its determination, via a referencing method which is not the subject of this presentation. Robot This body corresponds to the entire articulated chain, equipped with actuators, which allows the tool to be moved in space according to its six degrees of freedom. D robot K0 ^robot This reference frame is that of the end E1, E2 of the arm, its positioning relative to the reference frame Rbase = RQObot depends on the instruction given to the robot and evolves during the surgery. Its z axis corresponds to the longitudinal axis of the tool (its origin is arbitrarily placed on it), and its x and y axes are arbitrarily oriented. Tool This body corresponds to the surgical tool mounted on the robot and inserted into the patient's eye. The transformation of this body is known and fixed during surgery.D tool Ko pOUTil The origin II, 12 of this reference corresponds to the end of the tool (in the closed position for clampable tools) and its orientation is identical to that of the reference R”*®' = R“utii.

[0078]

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[0084] This reference is the one that allows the tool position commands to be materialized, by specifying the position of 1 in relation to the reference R®611. Thanks to the geometric model thus defined, it is possible to determine in any frame the expression of a point or a vector as soon as its expression in another frame is known. Eye Model - Determining the O Center of the Eye The eye is a special body since it depends on the patient and how the trocar of the tool is placed. The body oeill transforms the reference frame R°e111, of origin Tl and in which the tool positioning command is expressed, into a reference frame Ræ111, whose origin O corresponds to the center of the ball joint that exists between the eye and its orbit. Also, the body oeil2 transforms the reference frame R°eii2, of origin T2 and in which the tool positioning command is expressed, into a reference frame R^112, whose origin O corresponds to the center of the ball joint that exists between the eyeball and its orbit. Its transformation is a simple translation, defined by the position of point O in the frame R°eil\ R^'12 . Point O is defined theoretically, but in practice there is no means of measurement to locate it. A model of the eye is therefore set up to estimate this position. For this, the following quantities in relation to [Fig.2] are introduced: 1. the axial length AL; this is the distance between the apex of the cornea and the fovea. This is a common biometric data measurable during a preoperative examination. In the absence of a measurement, an average estimate of 23.8 mm is used, an estimate which can be made more precise by taking into account the patient's gender, age, origin and possible eye pathologies (see [Marilou thesis]). 2. the anterior chamber depth ACD; this is the distance between the top of the cornea and the top of the lens. This is a common biometric data measurable during a preoperative examination. In its absence, an average estimate of 3.17 mm can be retained, a value which can be refined according to the patient's characteristics (see [Marilou thesis]). 3. the white-to-white distance WW; this distance represents the horizontal diameter of the cornea. It is a common biometric data measurable during a preoperative examination. In its absence, an average estimate of 11.80 mm can be retained, a value which can be refined according to the patient characteristics (see [Hashemi]). 4. the limbus-trocar distance LT: this is the distance separating the limbus (edge ​​of the iris) from the insertion point of the trocar, measured radially relative to the iris. Vitreoretinal surgery trocars are supplied with a gauge to precisely respect a predefined distance, which depending on the supplier can vary between 3mm and 4mm (see [Kourous]). 5. the trocar opening angle a: this is the angle formed by the line (OT) and the longitudinal axis of the patient (from the feet to the head), projected onto the plane (xOy) of the R^11 reference point. This angle depends mainly on the surgeon's habits. It can be easily measured once the trocars are inserted, by the surgeon directly or by processing the images acquired by the microscope. In the absence of measurement, the current value of 60 degrees can be used.

[0085] The following hypotheses or approximations are also made:

[0086] - the diameter of the eyeball is equal to the difference between the axial length and the anterior chamber depth, and therefore its radius R is r — Qy _ 1 ( ÀL-ACD)

[0087] - the limbus belongs to the surface of the eyeball, therefore its distance from O is equal to R

[0088] - the two reference points of the distance LT and the vertical axis z are coplanar.

[0089] These five quantities and these three hypotheses make it possible to determine, using known geometric tools, the position of point O in the reference frames and RJ,0'12.

[0090] x= -RsinOsina x = Rsinôsina O = y - RsinÔcosa = y = RsinOcosa z = RcosO z = RcosO p eye 1 R0 robiIZ

[0091] 2 \) • -1 / LT \ 1 with t 1= Z [sin IJ2U-V1-) J / + sm (2R)

[0092] Definition of the operating scene and change of reference point

[0093] Thanks to a set of geometric transformations within the scene S, it is possible to locate any point in one of the reference points associated with each element of the scene.

[0094] To simplify the expression of the calculations with the transformations of the previous table, let us introduce the following notations (with RgOrps and R^”associated with the same body / element):

[0095] R^ to R^'1: transformation TOeii are defined to be oriented in the same way.

[0096] at R°rblte; transformation TOrbite, these two reference points have the same origin, the transformation is only a rotation.

[0097] ^Rbase orbit. Tbase transformation

[0098] R^ to Rrot»* ; TRobot transformation allows you to position the end of each arm in the scene

[0099] j^robot ; transformation T°ut11, the reference frame and the reference frame R y'"'1 are oriented in the same way: the TOuni transformation is a single translation along one dimension (here the tool axis) is necessary to move from one reference frame to another.

[0100] To move from one element to another, it is sufficient to refer to the geometric chain thus defined and, if necessary, define a succession of transformations.

[0101] The scene model thus obtained makes it possible to calculate the transformation which exists between two reference points.

[0102] Knowing the transformation that exists between two reference points of the model makes it possible to make changes of reference point: knowing the expression of a geometric object in a given reference point, it is possible to determine the expression of the same object in another reference point.

[0103] In the model thus constructed, three transformations are free: the transformation ^Orbit cl |cs transformations TRobot y yRobot2 pn giving a certain orientation to the eye we can determine TOrbit then it will be a question of determining which transformations yRoboti, yRobot2 will allow the end of the tools to be placed at given positions taking into account TOrblte-

[0104] Advantageously, since the axis of the tool must constantly pass through the trocar, the x and y coordinates of point T in the R*™1*1 frame are zero. This makes it possible to obtain a unique solution for the yRobot2 transformations. Control method (figure 4)

[0105] The control of the surgical device 10 is implemented by the control unit 7 and is based on a model of the operating scene (see below). In particular and as illustrated in [Fig. 3] a position instruction for the end II, 12 of each tool 41, 42 in their insertion point 52, 53 is received (steps REC1, REC2) by the control unit 7 as well as an orientation instruction for the eyeball in its orbit (step REC3).

[0106] Then, the geometric model of the corresponding operating scene is configured (step DET MOD) taking into account the positions and orientation received. This configuration of the model allows in particular the calculation (step TRANSI, TRANS2) of the transformations yrobotl jes robots which will place the ends E1, E2 of each arm so that the positions of the tools in the eye correspond well to the position instructions of the end II, 12 of each tool 41, 42 in their insertion point 52, 53, and so that the positions of the instantaneous centers of rotation of the tools ensure that the positions of the trocars correspond well to the position instructions of the insertion points 52, 53 generated by the desired orientation of the eyeball.

[0107] From the transformations calculated for each robot, each arm is piloted (PIL1, PIL2) according to these transformations. The piloting of the arms then consists of transmitting the transformations thus calculated to them as positioning instructions (PIL1, PIL2).

[0108] The piloting therefore makes it possible to move the tools in space to simultaneously position their ends at the desired locations and orient them so that they drive the insertion points and thus rotate the eye in its orbit.

[0109] The positions and orientation are calculated and sent to the control unit 7, to drive the arms 21, 22 accordingly, more than 1000 times per second for high transparency and thus follow the wishes of the user 9 who specifies the orientation (step DEFDj via the control station 7 and, possibly with the help of the imaging system 8 to control the operations.

[0110] The steps implemented by the control unit 7 for controlling the surgical device 10 are now described in detail.

[0111] In an initialization step (INIT step), - the position of the center O of the eye is determined by means of the eye model described above (INIT1). Then, from this position of the center O of the eye, the transformation T°eü is determined (INIT2) also from the positions of the insertion points 52, 53 which correspond to the origins of the reference points R°eiil, RJ]®*12.

[0112] Then, the Tbase transformation is determined (INIT3) using a known referencing method.

[0113] Each tool is positioned at the end El, E2 of each arm and the position of the end El, E2 of each arm in such a way that the transformation T°utd is either known in advance (thanks to a repeatable assembly) or determined by a referencing method (INIT4). In this respect, the end II, 12 of the tool is known relative to that of the end El, E2 of the arm.

[0114] Advantageously, the positioning of the reference R)]*01 relative to the reference R™blte is known and constant throughout the process and is the subject of any referencing method.

[0115] The tools being placed by the surgeon in their respective insertion point 52, 53, the method comprises the reception (REC1, REC2) by the control unit 7 of the positions of the tools in the reference points R^111, R['eii2 of origin the insertion points Tl, T2.

[0116] The position of the tools must change during surgery, in order to perform the surgical procedures desired by the surgeon. The determination of these positions can be the result of trajectory planning, or for a telemanipulation system, the result of a measurement on a dedicated interactor. We denote by I] / tt and I2 / to designate the positions of the ends II and 12 of each tool in the Ræ'n frame and in the Ræ112 frame.

[0117] Then, an orientation of the eyeball in its orbit, defined by a rotation (Qorbite)'* which orients the reference point Ræ11 associated with the eyeball 52 relative to the reference point R^te associated with the orbit (step DEFO) is defined by the surgeon by means of the control station 7. This rotation is then communicated to the control unit 7 (step REC3).

[0118] As already mentioned, steps REC1, REC2 and REC3 are implemented periodically (preferably more than 1000 times per second) for optimal transparency.

[0119] Furthermore, the orbit body is the common link in the two geometric chains of the robots. Its transformation reorients the reference frame associated with the center of the eye R^, to obtain a fixed reference frame relative to the patient's head: Rbase. It is made up of only one rotation, Qorbite. The inverse of this rotation, Qorbite4, describes how the eyeball is oriented relative to the patient's head. It is precisely this orientation that we wish to adjust and change during surgery, ^orbite4 can be described by three Euler angles 0X, $y and which, in convention ZYX, correspond to the rotation of the eye along the x and z axes of the reference frame R3 = Rbase.

[0120] These elementary rotations correspond to the elementary movements that the eye is capable of generating by the contraction or extension of muscles (in relation to [Fig.5]):

[0121] - 6X: rotation upwards or downwards, mainly resulting from contraction or extension of the inferior rectus muscles 53 and superior rectus muscles 54;

[0122] - 0y: rotation to the left or right, mainly resulting from contraction or extension of the internal rectus muscles 55 and external rectus muscles 56;

[0123] - 9 / : torsion rotation, mainly resulting from the contraction or extension of the inferior oblique muscles 57 and superior oblique muscles 58.

[0124] Since muscles have a limited capacity for contraction and extension, elementary rotations are also limited. The following conditions are therefore imposed ([Bargary et al.]): ÔXG [-48, +42] deg; 0y e [-50, +50] deg; ôx g [ - 30, + 30 ] deg.

[0125] The rotation ^Qorbîtey1, the positions 1^ and I2 / u constitute entries to a configuration of the entire geometric model of the scene (DET MOD step) to obtain the Toibite and Trobot transformations-

[0126] Indeed, once the positions of each tool and the rotation are defined, we know through the body chain how to go from the eye to the base and from the robot to the tool. It then remains to determine the link between the robot and the base which satisfies the positions of each tool and the rotation defined and which makes it possible to determine the robot control instructions: the transformations and p*01** presented above.

[0127] We first determine the j°rblte transformation (step SI) which is defined by the received rotation.

[0128] Then, for each robot, it is a question of determining from the received orientation and the position of the end of the tool in the reference frame R^11 the geometric transformation j-robot je so as to generate instructions for controlling the arm to place the end (El, E2) of the arm such that the end II, 12 of the tool is in a position such that the eyeball is oriented relative to its orbit according to the received orientation while being at the received position of the tool (step S2).

[0129] More precisely, to obtain the desired Trobote transformation, we seek the expression of the position of the end II, 12 of the tool and of the insertion point Tl, T2 in two different reference frames: the reference frame R^ (step S21) and the reference frame Rrobof (step S22).

[0130] The position of the insertion point T1, T2 in the frame Ræ1»1 (noted T / ^) is obtained by T / R?te= (T^d ) =14 0 0 \ with 77 / J corresponding to the -Z / desired depth of the tool in the eye, calculable directly with the position of the end of the tool in the eye (noted 1 / ^).

[0131] The position of the end of the tool in the Rrobot reference frame (denoted I / R™>«) is obtained by

[0132] The position of the insertion point T in the Rbase reference frame (denoted T / ri,„) is obtained by

[0133] 0 with Toeil Tbase involving 0 0 the rotation of the eyeball relative to the orbit and which makes it possible to define the transformation p0**®6 and known transformations Toeü and pbase.

[0134] Also the position of the end II, 12 of the tool in the reference frame is obtained by Tbase ( ) •

[0135] At this stage, the scene model is set as it must be to satisfy both the position and orientation setpoint of the globe.

[0136] Knowing for each robot the Trobot transformation which in other words positions the end El, E2 of the arm relative to the bases 31, 32, control instructions for each arm are calculated (steps CALC1, CALC2).

[0137] Each arm is finally controlled according to these instructions (steps PIL1, PIL2).

[0138] Definition of the eye rotation instruction (step DEF^)

[0139] To specify during surgery what rotation one wishes to give to the eyeball, several means can be implemented.

[0140] A first means of specifying the rotation of the eye consists of providing, on the pilot station, a dedicated interactor.

[0141] Two types of control can be considered: a position control or a speed control.

[0142] Command in position

[0143] With this type of control, the objective is to allow the user to directly indicate in which position he wishes to place the eye.

[0144] Several types of interactors can fulfill this role:

[0145] Graphical controls as seen in Figure 6: on a touchscreen, the user can directly specify the amplitude of the three elementary rotations 6X, 6y and constituting ^orbit-1. These values ​​can be set by adjusting the slider cursor, or more ergonomically by sliding the finger on a representation of the eye according to the desired adjustment direction.

[0146] A trackball type device visible in Figure 7: this type of device consists of a mobile ball in a fixed base. The ball can be rotated on itself by the user, and the device is capable of directly measuring the elementary rotations 6X, 0y and ©z corresponding to its orientation relative to the base. By assimilating the trackball ball to the eyeball, we can have a direct measurement of the rotation of the desired orbit Qorbite1.

[0147] Speed ​​control

[0148] With this type of control visible in Figure 8, the objective is to allow the user to choose a direction and a speed of rotation for the eye rather than directly its position. Joystick 71 or space mouse 72 type interactors can fulfill this role. In both cases, the device consists of a fixed support and a gripper which can be moved away from a central position in the three directions of space x, etz. The amplitude of the gripper is limited, and a reminder

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155] elastic tends to bring the gripper back to its central position so that it returns there as soon as it is no longer manipulated. These devices are capable of measuring how far the gripper is from its central position using elementary values ​​between -1 and 1 along each of the three axes: { £4} E [ -1 l]3 The values ​​{ Ex> C: j G {0,0, 0} are measured when the gripper is in the central position, while for each axis, the values ​​of -1 and 1 are measured when it reaches its maximum amplitude in one direction and in the other. With these devices, the values ​​of the elementary rotations 0x, 0y and 6 / can be periodically updated, preferably more than 100 times per second for optimal responsiveness: = 6x ExOmaxdt qv _ g + gvg with dt the update period and 9max the maximum variation g _ g + £ g of amplitude that we allow for each update A second way visible in [Fig.9] of specifying the rotation of the eye is to respond directly to the initial need to rotate the eye in its orbit: to allow the user to center a point of interest on the microscope images. An image I from the imaging system 4 is provided with a reference whose origin is a point C defined such that it appears at the center of the image when no rotation has been applied to the eye. There is a transformation which allows you to know the coordinates of a point in the j^bite frame from its coordinates in the frame. This transformation is determined from a recalibration method considered to be known. List of references#: [Marilou thesis] Marilou Isidore. Description of ocular biometric parameters in preoperative cataract surgery in a population in the South of France: a multicenter cross-sectional study. Human Medicine and Pathology. 2021. (dumas-03436986) [Hashemi et al.] Hashemi H, Khabazkhoob M, Emamian MH, Shariati M, Yekta A, Fotouhi A. White-to-white corneal diameter distribution in an adult population. J Curr Ophthalmol. 2015 Oct 19;27(l-2):21-4. doi: 10.1016 / j.joco.2015.09.001. PMID: 27239570; PMCID: PMC4877715. [Kourous] Kourous Rezaei MD, Complications in Vitreoretinal Surgery [Bargary et al.] Bargary, G., Bosten, J., Goodboum, P. et al. Individual differences in human eye movements: An oculomotor signature? 2017.

Claims

Claims

1. Surgical device (10) comprising at least two robots (11, 12), each robot (11, 12) comprising an articulated arm (21, 22) mounted on a base (31, 32), a tool (41, 42) being fixed to the end (El, E2) of the arm (21, 22), each tool comprising a distal end (II, 12) adapted to be inserted into an insertion point (Tl, T2) of an eye, the device comprising a control unit (7) configured to move the end (El, E2) of the arm of each robot, the control unit (7) being configured to implement the following steps for each robot: a) Receiving (REC1, REC2) a position instruction for the end (II, 12) of the tool expressed in a reference frame (Rgeül, Rq6'12) linked to the insertion point (Tl, T2) the tool being inserted into the eyeball of the eye, the eyeball being anatomically mobile in rotation relative to its orbit which is fixed relative to the base (31, 32) of the robots (11, 12);b) Reception (REC3) of an orientation instruction for the eyeball in the orbit; c) Configuration (DET MOD) of a model of a geometric scene defined by each robot and the eye, the geometric model making it possible to locate any point in a frame associated with an element of the scene, said configuration taking into account the position instructions received and the orientation instruction received; d) calculation (TRANSI, TRANS2) from the configured model of the transformation (-p"»^ yrobot2) je each robot defining the position and orientation of the end (El, E2) of each arm positioning the tools so as to obtain a globe oriented according to the orientation instruction received and placing the end of the tools according to the position instructions received; e) piloting (PIL1, PIL2) of each robot to position each arm according to the calculated transformation.;

2. Device according to the preceding claim, wherein the control unit is configured to implement a repetition of steps a) to c) to continuously position each arm (21, 22) according to the positions and orientation received in steps a) and b).

3.

4.

5. Device according to one of the preceding claims, in which the control unit (7) implements the configuration of the geometric model of the scene defined for each robot by a first transformation (yOeill jOeii2) known between a reference frame linked to the point of insertion of the tool in the eye and a reference frame linked to the center of the eyeball; a second transformation (y0^6) defined solely by a rotation between a reference frame linked to the center of the eyeball and a fixed reference frame linked to the center of the orbit, said rotation corresponding to the received orientation; a third transformation (yBasei5 yBaseï) known between the frame linked to the center of the orbit and a fixed frame linked to the base; a transformation of a robot (j^botl jrobot2^ between a reference frame linked to the end of the arm and the reference frame linked to the base, said transformation defining the position of the end of the arm in the reference frame linked to the base; a fourth transformation (joat'U joutil2) known between the reference frame linked to the end of the arm and the reference frame linked to the end of the tool. Device according to claim 3, wherein the control unit (7) is configured to in step d) implement the following sub-steps for each robot: dl) determining the coordinates of a vector between the insertion point and the end of the tool in the frame linked to the end of the arm from the position of the insertion point in the frame linked to the end of the arm obtained from the received position and the fourth known transformation; d2) determination of the coordinates of the vector between the insertion point and the end of the tool in the coordinate system linked to the base from the position of the insertion point in the coordinate system linked to the base obtained from the second and third transformations and the received position d3) calculation of the robot transformation from the coordinates of the vector obtained in steps dl) and d2). Device according to one of the preceding claims, in which the position of the insertion point (T1, T2) in the reference frame linked to the end (II, 12) of the tool depends on the position of the end (II, 12) of the tool in the reference frame linked to the insertion point, the end (El, E2) of the arm, the end (II, 12) of the tool and the insertion point (Tl, T2) being aligned. Claim 6] Device according to one of claims 3 to 4, in which the reference marks linked to the end of the tool and to the end of the arm are oriented in the same way, the fourth transformation being a single translation along the axis of the tool. Claim 7] Device according to one of the preceding claims, in which the control unit is configured to implement a determination of the position of the center (0) of the eye in the reference mark linked to the insertion point of the tool. Claim 8] Device according to claim 7,in which the position of the center (0) of the eye in the reference frame linked to the insertion point of the tool is determined by means of a model of the eye defined by - an axial length AL which is the distance between the top of the cornea and the fovea - an anterior chamber depth ACD distance between the top of the cornea and the top of the lens - a white-to-white distance WW: horizontal diameter of the cornea - a limbus-trocar distance LT: this is the distance separating the limbus, i.e. the edge of the iris, from the insertion point of the trocar, measured radially relative to the iris - the opening angle of the trocar: this is the angle formed by the line OT and the longitudinal axis of the patient from the feet to the head, projected onto the plane (xOy) of the reference frame R^d, model in which - the radius of the eyeball R is r — Qy — ~ (AL-ACD) - the limbus belongs to the surface of the globe ocular,its distance to 0 is equal to R; - the two reference points of the distance LT and the vertical axis z are coplanar the position of the point O in the reference frames linked to the eye noted R(JC|U and R“e112 being given by: x = -Rsinôsina x = Rsin9sina O = y = RsinÔcosa = y = RsinOcosa z = Rcos6 z = Rcos0 r> eye 1 ijeye2 Ko Kq with 0—7 uin'1 ( J- ( 1 \ / l ( I | — i I d-Vcc v — 2S sm y V 2 ' 1 ~ V1 - y 2R J / / sin yyi,

9. Device according to one of the preceding claims, comprising an imaging system (8) configured to acquire at least one image of the eye, a control system (6) being configured to specify a movement of the eye in combination with the acquired image of the eye and thus define a desired position of the eyeball to define the orientation of the eyeball in its orbit.

10. A device according to claim 9, wherein the control system comprises a touch control screen or a trackball so as to define the desired eye rotation.

Images