JP5284014B2 - Visual reproduction assist device - Google Patents

Description

  The present invention relates to a visual reproduction assisting device for reproducing the vision of a patient.

In recent years, as one of the techniques for treating blindness, research on visual regeneration assisting devices that attempt to regenerate vision by implanting in-vivo devices with a substrate on which multiple electrodes are formed and electrically stimulating cells that make up the retina Has been. Such a visual reproduction auxiliary device converts, for example, an image captured using an extracorporeal device into a predetermined signal and transmits it to an in-vivo device installed in the body, and outputs an electrical stimulation pulse signal from the electrode to output the retina An apparatus that attempts to regenerate vision by electrically stimulating cells (or tissues) that form a device is known (see, for example, Patent Document 1). In such an apparatus, the electrode is placed on the posterior eye portion of the patient's eye, and the return electrode (indifferent electrode) is placed in the vitreous body of the patient's eye.
JP 2004-57628 A

  In such an apparatus, since the electrical stimulation pulse signal output from the electrode flows toward the return electrode, the cells constituting the retina are penetrated by the electrical stimulation pulse signal and are efficiently electrically stimulated. However, the return electrode installed in the vitreous body is not preferable because it easily moves in the eye due to eye movement of the patient's eye.

  In view of the above-described problems of the prior art, it is an object of the present invention to provide a visual reproduction assisting device that can suppress the movement of the return electrode installed in the eye within the eyeball.

In order to solve the above problems, the present invention has the following configuration.
(1) a substrate on which a plurality of electrodes for electrically stimulating cells or tissues constituting the visual nervous system that forms the vision of a patient, a control means for outputting an electrical stimulation pulse signal from the electrodes, a retina In a visual reproduction assisting device comprising: a return electrode unit having a return electrode installed in an eyeball so as to face the plurality of electrodes sandwiched therebetween,
The return electrode part is
A return electrode formed of a biocompatible conductive material and long enough to penetrate the sclera of the anterior segment of the patient's eye and lie within the vitreous of the patient's eye;
A conducting wire for electrically connecting the return electrode and the control means;
A fixing part that is a separate member from the substrate and is provided at the proximal end of the return electrode, the fixing part being fixedly held in the sclera in a state where the return electrode is inserted into the eye from the sclera ,
It is characterized by having.
(2) In the visual reproduction assisting device according to (1), the return electrode is a rod-like member, and is attached to the fixing portion so as to extend in a substantially normal direction with respect to the contact surface of the fixing portion with the sclera. It is characterized by.

  ADVANTAGE OF THE INVENTION According to this invention, the movement in the eyeball of the return electrode installed in the eye can be suppressed.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an external appearance of a visual reproduction assistance device, and FIG. 2 is a diagram showing an in-vivo device in the visual reproduction assistance device.

  As shown in FIGS. 1 and 2, the visual reproduction assisting device 1 includes an extracorporeal device 10 for photographing the outside world, and an in-vivo device 20 that promotes visual reproduction by applying electrical stimulation to cells constituting the retina. The extracorporeal device 10 includes a visor 11 on which a patient is placed, an imaging device 12 including a CCD camera attached to the visor 11, an external device 13, a transmission unit 14 including a primary coil, and the like.

  The external device 13 is provided with a data modulation means 13a having an arithmetic processing circuit such as a CPU, and a battery 13b for supplying power to the visual reproduction auxiliary device 1 (external device 10 and internal device 20). The data modulation unit 13a performs image processing on the subject image captured by the image capturing device 12, and further converts the obtained image processed data into electrical stimulation pulse data for reproducing vision. The transmission means 14 transmits the electrical stimulation pulse data converted by the data modulation means 13a and the power for driving the in-vivo device 20 described later to the in-vivo device 20 side as a predetermined signal, in this embodiment, an electromagnetic wave ( Wireless transmission). A magnet (not shown) is attached to the center of the transmission means 14. The magnet is used to fix the position with the receiving means 31 described later.

  The visor 11 has an eyeglass shape, and can be used by being mounted in front of the patient's eyes as shown in FIG. The photographing device 12 is attached to the front surface of the visor 11 and can photograph a subject to be visually recognized by the patient.

  Next, the configuration of the intracorporeal device 20 will be described. FIG. 2 is a schematic diagram for explaining the in-vivo device 20, and the scale is schematically shown for convenience of explanation. 2A shows the appearance of the in-vivo device 20, and FIG. 2B is a cross-sectional view of the stimulation unit 40 and the return electrode unit 60 from the side direction. The in-vivo device 20 is roughly divided into a receiving unit 30 that receives data and electric power for electrical stimulation pulse signals transmitted from the extracorporeal device 10 by electromagnetic waves, and a stimulating unit 40 that electrically stimulates cells constituting the retina.

  The receiving unit 30 includes a receiving unit 31 including a secondary coil that receives an electromagnetic wave from the extracorporeal device 10 and a control unit 32 of the intracorporeal device 20. The control unit 32 separates the electrical stimulation pulse data and the power received by the receiving unit 31, and based on the electrical stimulation pulse data and the electrical power, an electrical stimulation pulse signal for obtaining vision, and the electrical stimulation pulse It has a role for converting the signal into a control signal including an electrode designating signal for designating an electrode corresponding to the signal (outputting an electrical stimulation pulse signal) and transmitting it to the stimulation unit 40.

  The receiving means 31 and the control unit 32 are formed on the substrate 33. The receiving unit 30 is provided with a magnet (not shown) for fixing the position of the transmitting unit 14. The return electrode unit 60 is arranged so that the return electrode 61 is placed in the vitreous body of the patient's eye (here, the vitreous body on the anterior eye side) and faces the electrode 44 across the retina. The return electrode unit 60 has a function to efficiently electrically stimulate cells and the like. Specifically, it indicates that the current path of the electrical stimulation pulse signal output from the electrode 44 is formed so as to penetrate the retina by arranging the feedback electrode 61 to be paired with each electrode 44. . The feedback electrode portion 60 is connected to the proximal end of the feedback electrode 61, the wire 55 that is a conductive wire for electrically connecting the feedback electrode 61 and the control unit 32, and the proximal end of the feedback electrode 61. A fixing unit 65 is provided for fixing the return electrode 61 to the sclera of the anterior segment of the patient's eye.

  The return electrode 61 is a rod-like member having a length that penetrates the sclera of the patient's eye and the tip of the return electrode 61 is located in the vitreous body. The return electrode 61 is a biocompatible and conductive material such as platinum. , Formed of a noble metal such as iridium. The return electrode 61 has a shape that easily penetrates the sclera. Here, the tip of the return electrode 61 has a needle shape (taper shape). In addition, the return electrode 61 has a rigidity that does not contact the intraocular tissue other than the vitreous body when the portion protruding into the vitreous body is inserted into the vitreous body due to eye movement of the patient's eye, etc. The diameter is such that the invasion to the sclera is reduced (the diameter that makes the wound as small as possible). The surface area of the return electrode 61 is determined so that an electrical stimulation pulse signal having a current density sufficient to stimulate the cells constituting the retina can be fed back to the control unit 32. Here, the return electrode 61 has a larger surface area than the one electrode 44. In the present embodiment, the shape (length, diameter) of the return electrode 61 is determined so that the surface area of the return electrode 61 is at least twice as large as the surface area of the electrode 44.

  The wire 55 is formed by using a conductive material having high biocompatibility, for example, a noble metal such as platinum as a wire, and covering the wire with a resin having high biocompatibility. The wire 55 has a thickness (diameter) that is flexible enough to fit the eyeball and is suitable for long-term installation. The aforementioned return electrode 61 is formed at the tip of the wire 55. The return electrode may be formed by peeling off the coating at the tip of the conducting wire and bending it.

  The fixing portion 65 is a member made of a biocompatible material, for example, a resin such as epoxy or polyparaxylylene, or a noble metal such as platinum. The fixing portion 65 is formed at the connection portion between the wire 55 and the return electrode 61 (the base end of the return electrode 61). As a result, the proximal end of the return electrode 61 is positioned in the vicinity of the electrode insertion opening of the return electrode 61 in the sclera with the tip of the return electrode 61 positioned in the vitreous body. In other words, the return electrode 61 is inserted into the eye, the fixing portion 65 comes into contact with the sclera, and accordingly, the tip of the return electrode 61 is located in the vitreous body.

  The relationship between the fixed portion 65 and the feedback electrode 61 is determined so that the feedback electrode 61 extends in a substantially normal direction with respect to a contact surface (or a tangential plane of the contact surface) that contacts the sclera of the fixed portion 65. Thereby, when the fixing | fixed part 65 is fixed to the sclera, the front-end | tip of the return electrode 61 will go to the center of a vitreous body. The feedback electrode 61 is formed with respect to the wire 55 so that the angle formed between the feedback electrode 61 and the wire 55 is substantially a right angle. Thereby, when the wire 55 is disposed along the curved surface of the eyeball and the return electrode 61 is inserted into the eyeball, the tip of the return electrode 61 is directed toward the center of the vitreous body (eyeball). From the above, it becomes difficult for the return electrode 61 to come into contact with the intraocular tissue (for example, the crystalline lens) of the anterior segment.

  In addition, the fixed portion 65 is shaped so that the contact surface in contact with the sclera can prevent the return electrode 61 inserted into the vitreous body from moving due to the eye movement of the patient's eye, etc. The plate shape is used. Further, since the fixing portion 65 is formed at the proximal end of the return electrode 61, the wire 55 does not easily protrude from the fixing portion 65. For this reason, when the return electrode part 60 is fixed to the sclera, the eye movement of the patient's eye is hardly hindered. Specifically, the fixing part 65 or the like is less likely to become a resistance in the patient's eye socket. Here, the thickness (thickness) of the fixing portion 65 is a thickness that does not interfere with the eye movement of the patient's eye when it contacts the sclera, and suppresses the movement of the return electrode 61 in the vitreous body. The thickness is such that it has sufficient rigidity.

  Here, when the return electrode 61 is inserted into the eye and the fixing portion 65 is in contact with the sclera, the fixing portion 65 is fixed to the sclera, so that the return electrode portion 60 is attached to the eyeball of the patient's eye. Fixed. In the present embodiment, the return electrode portion 60 is fixed by sewing the flat plate-shaped portion of the fixing portion 65 to the sclera with a suture thread. For this reason, the fixing portion 65 is composed of a pair of members extending on both sides with respect to the axis of the wire 55. Specifically, the long axis of the fixed portion 65 is formed so as to be substantially orthogonal to the axis of the wire 55. In the present embodiment, the suture is wound so as to be orthogonal to the long axis (a pair of members) of the fixing portion 65, and the fixing portion 65 is sewn to the sclera, whereby the fixing portion 65 is fixed. (See FIG. 3B). For this reason, even if stress is applied in the major axis direction of the fixed portion 65, the return electrode 61 becomes difficult to move. Specifically, it becomes difficult for the return electrode 61 to rotate in the vitreous body with the wire 55 in the vicinity of the fixed portion 65 as the rotation axis.

  In addition, the return electrode part 60 is produced in the following procedures. First, the return electrode 61, the fixing portion 65, and the wire 55 are individually manufactured. For example, when the fixing portion 65 is made of resin, the feedback electrode 61 and the fixing portion 65 are combined, and the wire 55 with the above-described covering is brought into contact with the feedback electrode 61. Thereafter, the return electrode 61 and the wire 55 are welded, and the joint portion is covered with a biocompatible resin or the like to obtain the return electrode portion 60. Note that the fixing portion 65 may be made of metal. In this case, three members may be welded, and the return electrode 61 may be left and other members may be covered with a resin or the like.

  Next, the configuration of the stimulation unit 40 will be described. The stimulation unit 40 includes a plurality of electrodes 44 that output electrical stimulation pulse signals, a stimulation control unit 42 (control means), and a substrate 43 on which these are installed. Each electrode 44 is formed on the substrate 43 in a square lattice pattern, for example, and each electrode 44 is connected to the stimulation control unit 42.

  The stimulation control unit 42 has a multiplexer function that distributes the corresponding electrical stimulation pulse signal to each of the electrodes 44 based on the control signal (including the electrode designation signal) sent from the control unit 32. A noble metal having high biocompatibility is used for the electrode 44. Each electrode 44 is formed by forming a noble metal thin film or cutting out from a noble metal lump. Since the substrate 43 is placed in the eye, particularly in the layered eye tissue, it is preferable to follow the shape of the eyeball, and it is preferable that the burden on the patient is small even if it is implanted in the interlayer (in the layer) for a long time. For this reason, the board | substrate 43 uses the thing processed into the flat form extended in the longitudinal direction from the raw material which has high biocompatibility and is bendable (flexible) in predetermined thickness. On the substrate 43, a wire 41 which is a conductive wire for electrically connecting the electrode 44 and the stimulation control unit 42 is disposed. The wire 41 is formed of a precious metal having high biocompatibility, and the thickness (diameter) of the wire 41 is set to a thickness that is preferable for flexibility and long-term installation of the substrate 43.

  The stimulus control unit 42 is a semiconductor integrated circuit that performs a function by a combination of semiconductor elements, and is bonded to the surface of the semiconductor substrate on which the pattern wiring for functioning the integrated circuit is formed. Although detailed description is omitted, the stimulus control unit 42 is covered with plating or the like to reduce infiltration from a living body. The stimulus control unit 42 may be configured to be sealed using an airtight case formed of ceramics or metal. In such a case, the stimulus control unit 42 is connected to the wire 41 via a via provided in the case.

  In addition, the receiving unit 30 and the stimulation unit 40 (stimulation control unit 42) placed at positions distant from each other in the body are connected and electrically connected by a plurality of wires (conductive wires). The plurality of conductive wires are embedded in a resin having biocompatibility so as to be easily handled and used as the cable 50.

  In addition, although illustration is abbreviate | omitted, the receiving part 30 takes out the cable 50 and the return electrode part 60, is accommodated in a highly airtight container, and the lid | cover of the container is sealed. Furthermore, it is coated from above the container with a resin having good biocompatibility and insulating properties. Thereby, the receiver 30 is hermetically sealed.

  Next, the installation state of such an in-vivo device 20 (stimulation unit 40 and return electrode unit 60) will be described. FIG. 3 is a schematic diagram illustrating a state in which the stimulation unit 40 and the return electrode unit 60 are implanted in the eye of the patient's eye E. 3A is a cross-sectional view of the patient's eye E, and FIG. 3B is an enlarged view of the anterior eye portion of the patient's eye E. As shown in FIG. 3A, in a state where the electrode 44 formed on the substrate 43 is in contact with the choroid E2 of the posterior eye portion, a part of the substrate 43 is between the sclera E3 and the choroid E2. Installed. Further, the stimulation control part 42 portion of the substrate 43 is placed outside the sclera E3. The substrate 43 is placed by incising a part of the sclera E3 to form a scleral pocket, and inserting the electrode portion of the substrate 43 into the scleral pocket (between the choroid E2 and the sclera). After installation, it is performed by fixing the substrate 43 by sewing or the like. In this embodiment, the electrode portion is placed between the sclera and the choroid. However, the present invention is not limited to this, and it can be placed in the sclera (in the sclera tissue).

  Further, as shown in FIG. 3B, the return electrode portion 60 is fixed to the sclera E3 near the outer periphery of the corneal ring portion L, which is near the boundary between the cornea C and the sclera E3 in the anterior segment. As shown in FIG. 3A, the return electrode 61 penetrates the sclera E3 of the anterior eye portion, and the tip of the return electrode 61 is inserted into the vitreous body. After the fixing portion 65 is in contact with the sclera E3, the fixing portion 65 is sewn to the sclera E3 with the suture thread S, whereby the feedback electrode portion 60 is fixed. At this time, the return electrode 61 is inserted into the eye from the electrode insertion opening formed in the sclera, and is positioned in the vicinity of the electrode insertion opening.

  In this way, the retina E1 is located between the electrode 44 and the return electrode 61. Since the electrical stimulation pulse signal output from the electrode 44 is directed to the feedback electrode 61, the electrical stimulation pulse signal penetrates (passes) the retina E1.

  On the other hand, the receiving means 31 is installed at a predetermined position in the living body that can receive signals (electric stimulation pulse data and power) from the transmitting means 14 provided in the extracorporeal device 10. For example, as shown in FIG. 1, the receiving unit 30 (only the receiving unit 31 is shown in the figure) is embedded under the skin of the patient's temporal region and transmitted to a position facing the receiving unit 30 through the skin. The means 14 is installed. Since the magnet is attached to the receiver 30 in the same manner as the transmitter 14, the transmitter 14 and the receiver 30 are attracted by the magnetic force by positioning the transmitter 14 on the implanted receiver 30. The transmission means 14 is held on the temporal region.

  The cable 50 and the wire 55 extend from the receiving unit 30 embedded in the temporal region under the skin toward the patient's eye along the temporal region, and are inserted into the eye socket through the inside of the patient's upper eyelid. The cable 50 placed in the eye socket passes through the outside of the sclera E3 as shown in FIG. 3A and is connected to the stimulation control unit 42 installed on the substrate 43. The wire 55 placed in the ophthalmologist passes through the outer side of the sclera E3 of the anterior eye part and is connected to the return electrode 61 as shown in FIG.

  The operation of the visual reproduction assistance device 1 having the above configuration will be described based on the control system block diagram of the visual reproduction assistance device 1 shown in FIG.

  The photographing data (image data) of the subject photographed by the photographing device 12 shown in FIG. 1 is sent to the data modulation means 13a. The data modulation means 13a converts the photographed subject into predetermined data parameters (electric stimulation pulse data) necessary for the patient to recognize, and further generates and transmits a modulation signal suitable for transmission as an electromagnetic wave. The electromagnetic wave is transmitted from the means 14 to the in-vivo device 20 side as an electromagnetic wave.

  At the same time, the data modulation means 13a transmits the power supplied from the battery 13b to the in-vivo device 20 side together with the modulation signal as an electromagnetic wave having a band different from the band of the modulation signal (electric stimulation pulse data) described above. .

  On the in-vivo device 20 side, the modulation signal and power sent from the extracorporeal device 10 are received by the receiving means 31 and sent to the control unit 32. The control unit 32 obtains power from the received signal and extracts a signal in a band used by the modulation signal, and forms an electrical stimulation pulse parameter signal and a control signal based on the modulation signal, A control signal is transmitted to the stimulus control unit 42.

  The stimulus control unit 42 extracts power and a control signal based on the received signal. The stimulation control unit 42 distributes the electrical stimulation pulse signal supplied from the control unit 32 to each electrode 44 based on the control signal, and outputs it. The electrical stimulation pulse signal output from each electrode 44 passes through the choroid E2 and the retina E1 toward the feedback electrode 61. Thereby, the cells constituting the retina E1 located in the vicinity of each electrode 44 are efficiently electrically stimulated, and the patient obtains vision (pseudo-light sensation).

  In the present embodiment described above, the fixing portion has a flat plate shape, but is not limited thereto. The fixing portion may have a configuration in which the contact surface of the fixing portion with respect to the sclera has a contact area that can suppress the movement of the return electrode in the vitreous body, and may have a rod shape or the like. Further, any configuration that can fix and hold the return electrode as described above may be used, and the configuration is not limited to the configuration in which the fixed portion is formed at the proximal end of the return electrode. For example, the fixing portion may be formed at the tip portion of the wire. For example, the shape of the tip end side of the wire coating may be a flat plate shape and may be the fixing portion. Alternatively, the side of the wire coating that contacts the sclera may be flattened to serve as a fixed portion.

  In the above-described embodiment, the feedback electrode portion is fixed to the eyeball by bringing the fixing portion into contact with the surface of the sclera and sewing the sclera. However, the present invention is not limited to this. Any configuration may be used as long as the return electrode portion is fixed to the anterior eye portion. For example, as described above, the sclera of the anterior eye part may be incised to form a scleral pocket, and the fixing part may be housed and fixed in the scleral pocket. In this case, the thickness of the fixing portion is set to a thickness that can be accommodated in the scleral pocket. In this case, the return electrode portion is fixed by suturing the incision portion of the sclera pocket or by sewing the fixing portion together with the sclera. Further, the fixing of the fixing portion is not limited to the suture. The structure which provides a tack etc. in the contact surface of the sclera of a fixing | fixed part may be sufficient. Further, the fixing part is not limited to the structure fixed to the sclera of the anterior eye part. It suffices if the tip of the return electrode is inserted into the vitreous body and the current path of the electrical stimulation pulse signal penetrates the retina, and the return electrode is viewed from the sclera behind the anterior segment (posterior pole side). The structure which inserts in and fixes a fixing | fixed part to a sclera may be sufficient.

  In the present embodiment described above, the sclera of the posterior eye is incised to form a scleral pocket, the stimulation unit is installed, and the cells constituting the retina are electrically penetrated by the electrical stimulation pulse signal. Although it was set as the structure which stimulates, it is not restricted to this. Any structure may be employed as long as the electrical stimulation pulse signal penetrates the cells or tissues of the visual nervous system constituting the patient's vision so as to reproduce the patient's vision. For example, the electrode may be installed below the retina (between the retina and the choroid), or may be installed on the optic nerve of the posterior segment. Moreover, you may arrange | position an electrode to an optic nerve. In this case, the current path of the electrical stimulation pulse signal is formed so as to penetrate the optic nerve.

1 is a schematic diagram showing an external appearance of a visual reproduction assisting device 1. FIG. It is the schematic which showed the in-vivo device 20 of the visual reproduction auxiliary | assistance apparatus 1. FIG. It is the figure which showed the state which installed the irritation | stimulation part 40 and the return electrode part 60 in the body. 3 is a block diagram showing a control system of the visual reproduction assisting device 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Visual reproduction | regeneration assistance apparatus 10 External apparatus 20 In-vivo apparatus 30 Receiving part 40 Stimulation part 44 Electrode 55 Wire 60 Return electrode part 61 Return electrode 65 Fixing part

Claims (2)

A substrate on which a plurality of electrodes for electrically stimulating cells or tissues constituting the visual nervous system forming the vision of the patient, a control means for outputting an electrical stimulation pulse signal from the electrodes, In a visual reproduction assisting device comprising a return electrode unit having a return electrode installed in an eyeball so as to face a plurality of electrodes,
The return electrode part is
A return electrode formed of a biocompatible conductive material and long enough to penetrate the sclera of the anterior segment of the patient's eye and lie within the vitreous of the patient's eye;
A conducting wire for electrically connecting the return electrode and the control means;
A fixing part that is a separate member from the substrate and is provided at the proximal end of the return electrode, the fixing part being fixedly held in the sclera in a state where the return electrode is inserted into the eye from the sclera ,
A visual reproduction assisting device comprising: 2. The visual reproduction assisting device according to claim 1, wherein the return electrode is a rod-like member, and is attached to the fixing portion so as to extend in a substantially normal direction with respect to a contact surface of the fixing portion to the sclera. Visual assisting device characterized by the above.