JP5284027B2 - 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, an electrode is placed on the posterior eye part (for example, in the sclera) of a patient's eye to electrically stimulate cells constituting the retina.
JP 2004-57628 A

  In such a visual reproduction assisting device, it is desired to electrically stimulate the cells constituting the retina. For this purpose, it is preferable that the contact state of each electrode with respect to the cells or tissue (eg, sclera) of the patient's eye, for example, the contact pressure with respect to the tissue is made as uniform as possible, and the stimulation conditions (states) of each electrode are made uniform. .

  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 influence on the living body and vision caused by different contact states of the electrodes with respect to the tissue.

In order to solve the above problems, the present invention has the following configuration.
(1)
A plurality of electrodes placed on the posterior eye portion for electrically stimulating cells forming a patient's retina formed in a predetermined pattern on the substrate, and outputting an electrical stimulation pulse signal connected to the electrodes from the electrodes A visual reproduction assisting device comprising control means,
The electrode formed on the substrate has a predetermined height, and the electrode height protruding from the substrate is non-uniform in order to align the contact state of the electrode with living tissue ,
In order to make the surface area of each electrode substantially the same, a concave shape, a convex shape, or a combination of concave and convex shapes for increasing the surface area according to the height of each electrode is formed on the side surface of the electrode. ,
It is characterized by that.
(2)
In the visual reproduction auxiliary device of (1),
The plurality of electrodes formed on the substrate are installed in a scleral pocket formed by incising the sclera, and the height of the electrode on the substrate located in the vicinity of the edge of the scleral pocket. Is lower than the height of the electrode located at the center of the scleral pocket.
(3)
In the visual reproduction assisting device according to (2), the electrode height of the plurality of electrodes gradually increases from an electrode arranged in the peripheral portion toward an electrode arranged in the central portion.

  ADVANTAGE OF THE INVENTION According to this invention, the influence on the biological body and vision by the contact state of each electrode with respect to a structure | tissue 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. 2A shows an external appearance of the in-vivo device 20, and FIG. 2B is a side sectional view of the stimulating unit 40. FIG. 3 is a perspective view showing the configuration of the electrode 44. 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. Further, the return electrode (indifferent electrode, counter electrode) 34 is placed in the eye and opposed to the electrode 44 with the retina interposed therebetween, so that cells and the like can be efficiently electrically stimulated. It is a member.

  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 to protrude on the substrate 43 at a predetermined height in a predetermined pattern (for example, a square lattice shape, a hexagonal lattice shape, or the like). In addition, each of the electrodes 44 is connected to the stimulus 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.

  Each electrode 44 is formed by forming a thin film of noble metal, which is a highly biocompatible conductor, or cutting out from a noble metal mass. In the present embodiment, the electrode 44 is a cylindrical member molded by cutting. The outer diameter of the electrode 44 is set to 100 to 500 μm, and the height to the apex of the electrode 44 protruding from the substrate 43 (hereinafter referred to as electrode height) is set to about 50 to 500 μm. Further, the tip (head) of the electrode 44 has a rounded shape so that the tissue of the posterior segment of the patient's eye such as the sclera and the electrode 44 come into contact with each other without causing a burden on the tissue. In addition, since the tip of the electrode 44 is rounded and the outer periphery of the electrode 44 is circular, the electrical stimulation pulse signal is output from the surface of the electrode 44 almost evenly. Although details will be described later, the electrode height of the electrode 44 is not uniform, and a groove 45 is formed on the side surface of the electrode 44 having a low electrode height.

  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. The thickness of the substrate 43 is 10 to 100 μm. 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 the flexibility and long-term installation of the substrate 43, for example, 10 to 100 μm. In addition, a notch is formed in a part of the side surface of the substrate 43 so that the base 43 can be easily bent in the longitudinal direction. Thereby, the board | substrate 43 becomes easy to follow along an eyeball.

  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. Further, the stimulation control unit 42 is hermetically sealed using an airtight case in order to suppress infiltration of body fluids and the like.

  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 biocompatible resin so as to be easily handled and used as the cable 50. Although not shown, the receiving unit 30 has an airtight terminal, and the internal electric circuit, the external cable 50, and the return electrode 34 are connected via the airtight terminal. Furthermore, it is coated from above the container with a resin having good biocompatibility and insulating properties.

  Next, the configuration and arrangement of the electrode 44 will be described. As shown in the drawing, in the present embodiment, the electrode height of the electrode 44 that protrudes from the substrate 43 is not uniform. By making the electrode height of the electrode 44 non-uniform, when the electrode 44 is placed in the posterior segment of the patient's eye, the contact state of the electrode 44 with the living tissue is aligned, and the stimulation conditions of each electrode with respect to the living tissue are different. The effect on the living body and vision is suppressed. The stimulation condition refers to a parameter other than the electrical stimulation pulse signal output from the electrode, and includes, for example, the contact pressure of the electrode with respect to the tissue. For example, when the contact pressure of the electrode is different, the tissue at a specific electrode position is stimulated, and the patient may feel light.

  A groove 45 is formed on the side surface of the electrode 44 according to the electrode height of the electrode 44. The groove 45 is a recess formed in a circumferential shape perpendicular to the protruding direction of the electrode 44. By forming the recess, the surface area of the electrode 44 is increased. In addition, the number of the grooves 45 formed in the 441 electrodes varies depending on the electrode height of the electrode 44 as illustrated. In addition, when the electrode height is reduced, the surface area (side area) of the electrode is reduced. On the other hand, the lower the electrode height, the more grooves 45 are formed, so that the surface areas of the respective electrodes 44 are substantially the same regardless of the electrode height. Thereby, the charge injection capability can be made substantially equal in each electrode 44. Note that the edge of the groove 45 is rounded to reduce the concentration of charges near the groove 45 when the electrical stimulation pulse signal is output from the electrode 44 (reducing the electric field concentration). ing). Thereby, it is possible to prevent the electric charge from being concentrated too much on the cells in the vicinity of the groove 45.

  In addition, the stimulation part 40 of this embodiment is inserted in the sclera pocket formed by incising the sclera of a patient's eye into a pocket shape, and is installed in a posterior eye part. An arrow I in the figure indicates the insertion direction of the substrate 43. Here, the electrode height of the electrode 44 is such that when the electrode 44 and the substrate 43 are placed in the scleral pocket, the contact pressure generated when each electrode 44 contacts the tissue is substantially equal. The electrode height is determined. Specifically, in the plurality of electrodes 44 arranged in a predetermined pattern, the electrode height of the peripheral electrode 44 is set lower than the electrode height of the central electrode 44. Furthermore, with respect to the insertion direction of the substrate 43, the electrode height of the electrode 44 located in the front and left / right directions (both sides) is set lower than that of the electrode 44 located in the center. Thus, when the electrode 44 and the substrate 43 are installed in the scleral pocket, the height of the electrode 44 on the substrate 43 located in the vicinity of the edge of the scleral pocket is positioned at the center of the scleral pocket. It becomes lower than the height of the electrode 44 (described later). Note that the electrode height of the electrode 44 gradually increases from the electrode 44 disposed in the peripheral portion toward the electrode 44 disposed in the central portion. In the present embodiment, in order to facilitate the insertion of the substrate 43 into the scleral pocket, the tip end portion (the front in the insertion direction) of the substrate 43 is rounded.

  Next, the installation state of such an in-vivo device 20 will be described. FIG. 4 is a schematic diagram illustrating a state in which the stimulation unit 40 is implanted in the eye of the patient's eye E. 4A is a cross-sectional view of the patient's eye E, FIG. 4B is a top transparent view of the scleral pocket P, and FIG. 4C is a cross-sectional view of the scleral pocket P. In FIG. 4, the illustration of the above-described members is partially omitted and the scale is partially changed for easy explanation.

  As shown in FIG. 4A, the tip of the substrate 43 is inserted into the sclera pocket P, and the electrode 44 is placed in the sclera E3. Further, the stimulation control part 42 portion of the substrate 43 is placed outside the sclera E3. Then, the stimulation part 40 is fixed to the posterior eye part of the patient's eye E by fixing the substrate 43 to the sclera E3 by suturing or the like. Here, the scleral pocket P is obtained by incising a part of the posterior eye of the patient's eye with a scalpel or the like, and incising the inside of the sclera E3 in a layered manner along the curved surface of the eyeball from the opening of the incised pocket. It is formed.

  As shown in FIG. 4B, the scleral pocket P has a size that allows the tip of the substrate 43 and the electrode 44 to be accommodated, and has a square shape in which the shape of the tip of the substrate 43 is slightly larger. The scleral pocket P is an opening A serving as an insertion opening of the substrate 43, and two peripheral end portions formed by being cut in a predetermined length from both ends of the opening A toward the peripheral end (edge) B. (Edge part) S and the peripheral end B formed on the opposite side of the opening A connected to the respective ends of the peripheral end S. The end portions S and B are the edge portions of the scleral pocket P. In the figure, a solid line indicates an incision (separation) location, and a dotted line indicates a location where the sclera E3 is connected (not incision).

  The sclera E3 of the scleral pocket P has a restoring force (elastic force, contraction force) that closes toward the inner side (choroid E2) of the sclera E3. In particular, the sclera E3 in the vicinity of the end portions S, B, etc., is difficult to expand because the sclera E3 is not incised. Therefore, in the vicinity of the end portions S, B, etc., the restoring force is higher than that of the central portion of the scleral pocket P. For this reason, the board | substrate 43 and the electrode 44 which are installed in the scleral pocket P will be squeezed inward from the sclera E3. The inner sclera E3 also has a restoring force and has a resistance against the pressing force from the electrode 44 and the like.

  As shown in FIG. 4C, the substrate 43 and the electrode 44 installed in the scleral pocket P are pressed inward by the sclera E3. At this time, in the vicinity of the end portion S, the restoring force of the sclera E3 (the force for holding the electrode 44 by the sclera E3) increases. As a result, the electrode 44 located at the end S is pressed more strongly than the electrode 44 at the center.

  For this reason, as described above, the electrode height of the peripheral electrode 44 (both sides in the figure) is made lower than that of the central electrode 44, so that the sclera E3 and the electrode 44 (seven in the horizontal row in the figure) ) Contact pressure is substantially equal. Further, by gradually increasing the electrode height of the electrode 44 from the peripheral part toward the central part, the electrode 44 is preferably brought into contact with the surface of the sclera E3 that is curved when the scleral pocket P is opened. . In addition, it is preferable that the change of the electrode height which goes to a center part from a peripheral part is defined so that the curvature of the sclera E3 may be followed.

  In the above description, the electrode height on both sides of the substrate 43 has been described with reference to the cross-sectional view of the scleral pocket P crossing the end portion S. However, the electrode 44 positioned at the tip of the substrate 43 is also described. It is the same. In this case, the electrode height gradually increases from the peripheral electrode 44 located in the vicinity of the end B toward the electrode 44 located in the center. Thereby, when the electrode 44 is installed in the sclera pocket P, the contact pressure of the electrode 44 to the sclera E3 is made substantially equal. Further, since the electrode 44 at the tip (front) is low, the substrate 43 and the electrode 44 can be easily inserted into the scleral pocket P.

  As described above, the contact state between the respective electrodes 44 installed in the sclera pocket and the choroid E2 can be aligned regardless of the position of each electrode. For this reason, the influence on the living body and the vision due to the contact state of each electrode differing from the living tissue is suppressed. Thereby, the stimulation conditions of each electrode are prepared, and the cells constituting the retina are preferably electrically stimulated.

  In the present embodiment, the electrode 44 is placed in the sclera E3. However, the present invention is not limited to this and may be placed between the sclera E3 and the choroid E2.

  On the other hand, the return electrode 34 is placed in the eye (in the vitreous body) as shown in FIG. Therefore, the retina E1 is positioned between the electrode 44 and the return electrode 34. Since the electrical stimulation pulse signal output from the electrode 44 is directed to the feedback electrode 34, the electrical stimulation pulse signal passes through the retina E1.

  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 extends from the receiving unit 30 embedded in the temporal region under the skin toward the patient's eye along the temporal region, and is 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 outer side of the sclera E3 as shown in FIG. 4A and is connected to the stimulation control unit 42 installed on the substrate 43.

  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 sclera E3, the choroid E2, and the retina E1 toward the feedback electrode 34. And the cell which comprises the retina E1 is stimulated efficiently, and a patient acquires vision (pseudo-light sensation).

  In the above-described embodiment, the electrode (stimulation unit) is configured to be installed in the sclera pocket. However, the present invention is not limited to this. The electrode may be installed in the posterior segment of the patient's eye and the cells constituting the retina can be electrically stimulated, and the electrode may be installed below or on the retina. In this case, a stimulation part having an electrode height along the retina having a curved surface is used. For example, when a stimulating part is installed under the retina, the electrode height of the peripheral part of the electrodes arranged in a certain pattern is set to make the contact pressure of the electrode that contacts the convex retina substantially equal when viewed from the stimulating part side. Make it higher than the center. In addition, when the aesthetic part is installed on the retina, the electrode height of the peripheral part of the electrode arranged in a certain pattern is set in order to make the contact pressure of the electrode that contacts the concave retina viewed from the stimulation part side substantially equal. Lower than the center.

  In the present embodiment described above, grooves that are concave portions are provided on the side surfaces of the electrodes so that the surface areas of the electrodes having different electrode heights are substantially uniform. However, the present invention is not limited to this. For the purpose of suppressing the difference in surface area based on the non-uniformity of the electrode, it is only necessary to form different side shapes depending on the electrode height. For example, the shape of the concave portion is not limited to the groove, and may be a concave portion with an enlarged surface area such as a hole or a notch. Moreover, you may form the shape of the whole electrode not by recessed parts, such as a groove | channel, but by the combination of a convex part and an unevenness | corrugation.

  In the above-described embodiment, the plurality of electrodes having different electrode heights are configured such that the electrodes have recesses and the charge injection capability of the electrodes is substantially uniform. However, the present invention is not limited to this. In other words, as long as the electrode has a sufficient charge injection capability, in other words, if the surface area of the electrode is sufficiently large, it is not necessary to form a recess in an electrode having a different electrode height.

It is the schematic which showed the external appearance of the visual reproduction auxiliary | assistance apparatus. It is the schematic which showed the internal body apparatus of a visual reproduction assistance device. 3 is a perspective view showing a configuration of an electrode 44. FIG. It is the figure which showed the state which installed the stimulation part 40 in the body. It is the block diagram which showed the control system of the visual reproduction auxiliary | assistance apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Visual reproduction | regeneration assistance apparatus 10 External apparatus 20 In-vivo apparatus 30 Receiving part 31 Receiving means 32 Control part 34 Return electrode 40 Stimulation part 42 Stimulation control part 43 Board | substrate 44 Electrode 45 Groove

Claims (3)

A plurality of electrodes placed on the posterior eye portion for electrically stimulating cells forming a patient's retina formed in a predetermined pattern on the substrate, and outputting an electrical stimulation pulse signal connected to the electrodes from the electrodes A visual reproduction assisting device comprising control means,
The electrode formed on the substrate has a predetermined height, and the electrode height protruding from the substrate is non-uniform in order to align the contact state of the electrode with living tissue ,
In order to make the surface area of each electrode substantially the same, a concave shape, a convex shape, or a combination of concave and convex shapes for increasing the surface area according to the height of each electrode is formed on the side surface of the electrode. ,
A visual reproduction assisting device characterized by that. The visual reproduction assisting device according to claim 1, wherein
The plurality of electrodes formed on the substrate are installed in a scleral pocket formed by incising the sclera, and the height of the electrode on the substrate located in the vicinity of the edge of the scleral pocket. Is lower than the height of the electrode located at the center of the scleral pocket.   3. The visual reproduction assisting device according to claim 2, wherein the electrode height of the plurality of electrodes gradually increases from an electrode disposed in the peripheral portion toward an electrode disposed in the central portion. apparatus.