Abstract: An intraocular implant device for comprehensive intraocular vision advancement includes an intraocular implant body shaped for positioning inside a lens chamber of an eye. In some embodiments, the implant includes an optical adjustable base accommodating lens configured to provide both base adjustment and accommodation. In further embodiments, the implant includes a photoelectric sensor operable to receive incident light through the cornea and to convert the received light into electrical energy for use with one or more circuit components disposed on the body, and wherein the photoelectric sensor is also operable to convert the received light into image data. The ocular implant device may include a projector for projecting the an image representative of the image data onto the retina of a user.

Abstract: Surgical implants and methods to improve, support, or help to preserve vision by altering the axial length or curvature of an eye are provided. Staphyloma supporting devices or implants can be of unitary construction from a single base material such as titanium alloy and can have a macular indenter plate wider than the implant body and an anchor structure wider than the macular indenter plate. A compound concavity scleral contact surface can approximate the outer surface of the eye with an anterior radius of curvature and can restore macular shape and axial length with a second posterior radius of curvature that can be less than the anterior radius of curvature.

Abstract: Apparatus is provided that includes a retinal stimulator, which includes an electrode array including electrodes, which are configured to be coupled to a retina of a subject's eye; and driving circuitry, configured to drive the electrodes to apply currents to the retina. The retinal stimulator further includes an elastic anchor that is coupled to the retinal stimulator and is configured to anchor the electrodes to the retina without the elastic anchor penetrating the retina. Other embodiments are also described.

Abstract: An artificial retina system based on an augmented reality according to an embodiment of the present disclosure may include an external device and an artificial retina device. The external device may be disposed outside the human body, and may include a micro display providing a processed image which is image-processed based on external image information obtained by capturing an external region of a human body; and the artificial retina device may be disposed in an eyeball inside the human body, and may provide a retinal tissue included in the human body with an electrical signal corresponding to the processed image provided by the micro display.

Abstract: Methods and apparatuses to detect configuration commands from waveforms received at a retina prosthesis device for calibrating the device are described. The device can comprise an array of pixel units to receive light to stimulate neuron cells to cause an effect of visual sensation from the light. The pixel units may have configurable parameters for the stimulation to the neuron cells. The configurable parameters may be updated according to the configuration commands detected without requiring micro processor and non-volatile memory in the device. The stimulation may be generated according to the updated configurable parameters to improve the effect of visual sensation from the light including compensation for the physiological and environmental variations and drifts.

Abstract: Photoreceptor scaffolds and scaffold systems including the photoreceptor scaffolds are described herein. The scaffolds and scaffold systems can be used for transplantation of organized photoreceptor tissue, with or without RPE, which may improve grafted cell survival, integration, and functional visual rescue. Particularly, the photoreceptor scaffold is structured from a biocompatible film, patterned with an array of unique through-holes having a curvilinear cell receiver and at least one cell guide channel.

Abstract: Implantable nerve transducers are provided herein, along with methods of fabricated such implantable nerve transducers. An exemplary implantable nerve transducer includes a plurality of semiconductor structures protruding from an exterior surface provided by a substrate and a plurality of conductors extending from the exterior surface of the substrate to an interior surface of the substrate and within a plurality of openings in the substrate. Each conductor is electrically coupled to one of the semiconductor structures. The exemplary implantable nerve transducer further includes one or more electronic components electrically coupled to the semiconductor structures by the conductors and a cap bonded to the substrate to provide a sealed chamber. The sealed chamber contains the one or more electronic components.

Abstract: The present invention refers to a photosensitive pixel structure (10) comprising a substrate (15) with a front surface and a back surface, wherein at least one photosensitive diode (12, 12?) is provided on one of the surfaces of the substrate (15). A first material layer (30) is provided at least partially on the back surface of the substrate (15), wherein the material layer (30) comprises a reflective layer, in order to increase a reflectivity at the back surface of the substrate. Further, the present invention refers to an array (1) and an implant comprising such a photosensitive pixel structure (10), as well as to a method to produce the pixel structure (10).

Abstract: In electrically stimulating neural tissue it is important to prevent over stimulation and unbalanced stimulation, which would cause damage to the neural tissue, the electrode, or both. It is critical that neural tissue is not subjected to any direct current or alternating current above a safe threshold. Further, it is important to identify defective electrodes, as continued use may result in neural damage and further electrode damage. The present invention presents system and stimulator control mechanisms to prevent damage to neural tissue.

Abstract: A subretinal prosthetic device includes a substrate provided under a retina, a return electrode for receiving a current such that a ground is formed on the substrate, a plurality of stimulating electrodes provided on the substrate and for generating an active potential to an optic nerve in response to external visual information projected onto the retina, and a switch for controlling the current between each of the plurality of stimulating electrodes and the return electrode. The switch is connected between the plurality of stimulating electrodes and the return electrode to ground the plurality of stimulating electrodes to the return electrode in response to an on or off control signal.

Abstract: An apparatus for delivering therapeutic agent to an eye comprises a body, a cannula, a hollow needle, and an actuation assembly. The cannula extends distally from the body and is sized and configured to be insertable between a choroid and a sclera of a patient's eye. The actuation assembly is operable to actuate the needle relative to the cannula to thereby drive a distal portion of the needle along an exit axis that is obliquely oriented relative to the longitudinal axis of the cannula. The cannula may be inserted through a sclerotomy incision to position a distal end of the cannula at a posterior region of the eye, between the choroid and sclera. The needle may be advanced through the choroid to deliver the therapeutic agent adjacent to the potential space between the neurosensory retina and the retinal pigment epithelium layer, adjacent to the area of geographic atrophy.

Abstract: An artificial retinal prosthesis system comprises an extraocular optical device and an intraocular retina chip. The extraocular optical device receives an external image, converts it into an optical pulse signal, and generates light energy. The intraocular retina chip receives the optical pulse signal from the extraocular optical device and produces an electric simulation signal. The intraocular retina chip includes a solar cell module receiving and converting the light energy into electric energy as a power source of the intraocular retina chip. The artificial retinal prosthesis system uses an optical modulation method to convert an image signal into an optical pulse signal, transmits the optical pulse signal into the eyeball, and decodes the optical pulse signal intraocularly. Thereby, the signal light intensity is improved without affect the contrast ratio.

Abstract: A retinal prosthesis system can comprise: a flexible substrate; a nanowire light detector which is placed on the substrate, and comprises one or more nanowires of which the resistance changes according to the applied light; one or more micro-electrodes which are placed on the substrate, are electrically connected to the nanowire light detector, and come in contact with retinal cells; and an electric power supply source for applying electric power to the nanowire light detector and the micro-electrodes. The retinal prosthesis system can be implemented into a very thin and flexible substrate type high resolution retinal system by manufacturing a nanowire light detector on a substrate in which micro-electrodes are implemented.

Abstract: The present invention is a visual prosthesis which restores partial vision to patients blinded by outer retinal degeneration. While visual prosthesis users have achieved remarkable visual improvement to the point of reading letters and short sentences, the reading process is still fairly cumbersome. In the present invention the visual prosthesis is adapted to stimulate visual braille as a sensory substitution for reading written letters and words. The visual prosthesis system, used in the present invention, includes a 10×6 electrode array implanted epiretinally, a tiny video camera mounted on a pair of glasses, and a wearable computer that processes the video and determines the stimulation current of each electrode in real time.

Abstract: The present invention consists of an implantable device with at least one package that houses electronics that receives input data or signals, and optionally power, from an external system through at least one coil attached to the at least one package, processes the input data and delivers electrical pulses to neural tissue through at least one array of multiple electrodes that is/are attached to the at least one package. The invention, or components thereof, is/are intended to be installed in the head, or on or in the cranium or on the dura, or on or in the brain.

Abstract: The present invention comprises an implant for placing inside the eye such that the implant comes into contact with the interior tissue of the eye such that it conforms to the inner globe geometry of the eye. Implants of the present invention may also be used to alter the focal length of the eye thereby providing a treatment method for the correction of myopia and hyperopia. The device may consist of several possible configurations, an open mesh structure, a solid metal ring, a solid polymer shape, a mesh polymer shape or combination of these. The shape may be a curve, a sphere, a ring or a combination thereof that are specifically shaped to approximate a desired portion of the interior globe of the eye in order to treat myopia or hyperopia.

Abstract: Providing an electrode structure capable of realizing an electrode array which allows each of the electrodes to be individually controlled while allowing them to be densely arranged and placed in a living body. According to the present invention, an electrode control circuit electrically connected to an electrode body is fixed to a rear portion of the electrode body within a front-viewed contour of the electrode body. This electrode control circuit may be contained in a recess formed in the rear portion of the electrode body, or it may be fixed to the back face of the electrode body. Conversely, an electrically conductive material layer covering the electrode control circuit may be used as the electrode body. A plurality of such bioelectrodes may be arranged in a two-dimensional form on a substrate or connected by a connection line including an electrical wire. Such configurations allow the bioelectrodes to be densely arranged.

Abstract: An implantable neural stimulator includes one or more electrodes, a dipole antenna, and one or more circuits and does not include an internal power source. The one or more electrodes are configured to apply one or more electrical pulses to neural tissue. The dipole antenna is configured to receive an input signal containing electrical energy utilizing electrical radiative coupling (for example, in the frequency range form 300 MHz to 8 GHz). The one or more circuits are configured to create one or more electrical pulses using the electrical energy contained in the input signal; supply the electrical pulses to the electrodes such the electrical pulses are applied to neural tissue; generate a stimulus feedback signal; and send the feedback to the dipole antenna to transmit to the second antenna through electrical radiative coupling.

Abstract: Apparatus is provided having an intraocular device for implantation entirely in a subject's eye, the intraocular device including: a photosensor array having a plurality of photosensors, each photosensor detects ambient photons and generates a signal in response thereto. A spatial density of the photosensors in a central portion of the array is greater than a spatial density of the photosensors in an outer portion of the array. The intraocular device additionally includes a plurality of stimulating electrodes and driving circuitry coupled to the photosensors, and configured to drive the electrodes to apply electrical pulses to a retina of the eye in response to the signals from the photosensors. Other applications are also described.

Abstract: The present invention is an improved method of electrically stimulating percepts in a patient with a visual prosthesis, to induce the perception of color. In particular, the present invention is a method of inducing the perception of color by determining experimentally which patterns induce which colors, storing that information and using the stored information to induce the perception of color according to video input data and the stored color information.

Abstract: This disclosure provides a retinal prosthetic method and device that mimics the responses of the retina to a broad range of stimuli, including natural stimuli. Ganglion cell firing patterns are generated in response to a stimulus using a set of encoders, interfaces, and transducers, where each transducer targets a single cell or a small number of cells. The conversion occurs on the same time scale as that carried out by the normal retina. In addition, aspects of the invention may be used with robotic or other mechanical devices, where processing of visual information is required. The encoders may be adjusted over time with aging or the progression of a disease.

Abstract: The invention is a method of automatically adjusting an electrode array to the neural characteristics of an individual patient. By recording neural response to a predetermined input stimulus, one can alter that input stimulus to the needs of an individual patient. A minimum input stimulus is applied to a patient, followed by recording neural response in the vicinity of the input stimulus. By alternating stimulation and recording at gradually increasing levels, one can determine the minimum input that creates a neural response, thereby identifying the threshold stimulation level. One can further determine a maximum level by increasing stimulus until a predetermined maximum neural response is obtained.

Abstract: A three-coil electromagnetic induction power transfer system is disclosed for epiretinal prostheses and other implants. A third, buffer coil is disposed between an external transmitting coil and a receiver coil buried within the body to improve efficiency and robustness to misalignments. One or more of the coils can be manufactured using micromechanical machining techniques to lay out conductors in a ribbon of biocompatible insulator, folding lengths of the insulated conductor traces longitudinally over one another, and then spiraling them into a ring. The traces change axial position in the ring by shifting across fold lines. One or more U-shaped sections on the traces can be folded so that adjacent traces can project opposite one another, lengthening the resulting ribbon that can be wound into a coil.

Abstract: A retinal prosthesis including an electronic stimulation unit housed inside an eye and including: a plurality of electrodes that contact a portion of a retina of the eye; an electronic control circuit, which is electrically connected to the electrodes and supplies to the electrodes electrical stimulation signals designed to stimulate the portion of retina; and a local antenna connected to the electronic control circuit. The retinal prosthesis further includes an electromagnetic expansion housed inside the eye and formed by a first expansion antenna and a second expansion antenna electrically connected together, the first expansion antenna being magnetically or electromagnetically coupled to an external antenna, the second expansion antenna being magnetically or electromagnetically couple to the local antenna, the electromagnetic expansion moreover receiving an electromagnetic supply signal transmitted by the external antenna and generating a corresponding replica signal.

Abstract: Methods and apparatuses for configuring an implantable device to interface with retina cells are described. The device may comprise an array of pixel units capable of stimulating the retina cells are described. The pixel units may operate in a mode of operation selected from a plurality of modes including a normal mode and a calibration mode. A control circuitry of the device may be configured to switch the mode of operation for the pixel units. In one embodiment, the pixel units may be configured to receive light for stimulating the retina cells during the normal mode to enable perception of the light. During the calibration mode, the pixel units may be configured to adjust amount of stimulation to the retina cells.

Abstract: The present invention relates to biocompatible compositions for transplantation into a sub-retinal space of the human eye. The compositions include a biodegradable polyester film, preferably a polycaprolactone (PCL) film, and a layer of human retinal progenitor cells. The compositions of the invention can be used as scaffolds for the treatment a number of ocular diseases, including retinitis pigmentosa and age-related macular degeneration.

Abstract: A method for manufacturing an intraocular retinal implant including: providing a mold capable of supporting growth of a layer of doped diamond, the mold including, on one face, elements all depressed or all projecting with respect to the surface of the face, and constituting a pattern cavity for the electrodes of the implant which it is desired to obtain; producing the doped diamond electrodes by growing a layer of doped diamond in all or part of a space occupied by the pattern cavity elements; forming a first insulating layer on the face of the mold including the pattern cavity; producing interconnection lines by depositing an electrically conductive material at least in spaces not covered by the first insulating layer; forming a second insulating layer on the mold face including the pattern cavity, the second layer covering the interconnection lines, the first and second insulating layers forming a flexible plate of the implant; removing the mold.

Abstract: A device and method is disclosed for preventing glaucomatous optic neuropathy, an affliction of the eye. An incision is made in the scleral region of the eye and an optic nerve head shield is inserted and positioned proximate to the optic nerve head of the eye to form a pressure seal over the optic nerve head of the eye. The optic nerve head shield decreases the pressure differential across the cribiform plate preventing bowing of the cribiform plate and glaucomatous optic neuropathy.

Abstract: A device which may be formed of suitable elastomeric, biocompatible material is configured to be wedged into Tenon's space between the orbital and scleral walls of the eye at the location of a retinal tear or break. When positioned, the device pushes the eye wall inward to close the tear, and fluid below the retinal wall resorbs.

Abstract: An artificial retinal system includes an external optical device having an image generator and a background light generator, and a retinal implant chip having a solar cell and a stimulus generator. The stimulus generator is disposed to receive a target image projected by the image generator and a background light provided by the background light generator, and receives the electrical power from the solar cell. The stimulus generator includes an image sensing stimulator operable to convert the target image into electrical stimuli, and a contrast enhancer for reducing effect of the background light on the electrical stimuli.

Abstract: A prosthetic retina for implantation in an eye having a defective retina is formed from an array of nanowires having a predetermined spatial distribution, density, size and shape implanted in close proximity to the retina. An electrical conductor is formed at a first end of all nanowires in the array of nanowires and placed in contact with a bias source which biases the array. A plurality of electrodes is located on a second end of each of one nanowire or a bundle of nanowires in the array. Each nanowire produces a photocurrent at a corresponding electrode in response to detection of light impinging on the array of nanowires and the photocurrent stimulates one or more neurons adapted for visual perception. In the preferred embodiment, the predetermined spatial distribution mimics a distribution of rods and cones in a normal eye.

Abstract: An improved prosthesis and method for stimulating vision nerves to obtain a vision sensation that is useful for the patient that has lost vision due to age-related macular degeneration (AMD) and retinitis pigmentosa (RP) and other diseases. The present invention utilizes infrared light to cause action potentials in the retinal nerves similar to those which result from rods and cones stimulated by visible light in healthy retinas. In some embodiments, the invention provides a pathway or “image pipe” for transmitting a stimulation pattern of infrared light from an external stimulator array through the eye and focusing the stimulation pattern of infrared light on the retina, especially the fovea. Some embodiments provide improved resolution down to a group of nerves, or even the individual nerve level, with sufficient energy density so as to cause a desired action potential.

Abstract: The scleral epimacular implant comprises an arm (6) with a curved configuration, having a first end (1), which can be affixed to a retina (8). The arm (6) comprises a second end (3) comprising a discoidal element (4), whose internal face facing the curvature of the arm (6) is constituted as an indentation platform (5), configured to be in contact with the retina (8) when the implant is placed in said retina (8).

Abstract: A medical device includes an array of electrodes, configured for implantation in contact with tissue in an eye of a living subject. Driver circuitry is configured to drive the electrodes in an alternating pattern, such that different groups of the electrodes are driven to stimulate the tissue during different, predetermined respective time periods. A power sensor, may be coupled to deactivate a first group of the electrodes when the available electrical power drops below a predetermined threshold, while a second group of the electrodes remains active. Other embodiments are also described.

Abstract: A retinal prosthesis system can comprise: a flexible substrate; a nanowire light detector which is placed on the substrate, and comprises one or more nanowires of which the resistance changes according to the applied light; one or more micro-electrodes which are placed on the substrate, are electrically connected to the nanowire light detector, and come in contact with retinal cells; and an electric power supply source for applying electric power to the nanowire light detector and the micro-electrodes. The retinal prosthesis system can be implemented into a very thin and flexible substrate type high resolution retinal system by manufacturing a nanowire light detector on a substrate in which micro-electrodes are implemented.

Abstract: The present invention is an improved method of electrically stimulating percepts in a patient with a visual prosthesis, to induce a more controlled perception of light. In particular, the present invention is an improved electrode array to maximize retinal response. The array of the present invention is an array with a center section with no electrode, surrounded by a ring of small high density electrodes. Electrodes beyond to ring are gradually larger and more widely spaced.

Abstract: The invention provides chip packaging and processes for the assembly of retinal prosthesis devices. Advantageously, photo-patternable adhesive or epoxy such as photoresist is used as glue to attach a chip to the targeted thin-film (e.g., parylene) substrate so that the chip is used as an attachment to prevent delamination.

Abstract: A retinal prosthesis including an electronic stimulation unit housed inside an eye and including: a plurality of electrodes that contact a portion of a retina of the eye; an electronic control circuit, which is electrically connected to the electrodes and supplies to the electrodes electrical stimulation signals designed to stimulate the portion of retina; and a local antenna connected to the electronic control circuit. The retinal prosthesis further includes an electromagnetic expansion housed inside the eye and formed by a first expansion antenna and a second expansion antenna electrically connected together, the first expansion antenna being magnetically or electromagnetically coupled to an external antenna, the second expansion antenna being magnetically or electromagnetically couple to the local antenna, the electromagnetic expansion moreover receiving an electromagnetic supply signal transmitted by the external antenna and generating a corresponding replica signal.

Abstract: Multilayer protein films are provided, which comprise native bacteriorhodopsin and/or specialized bacteriorhodopsin mutants as the photoactive element. Also provided are artificial subretinal and epiretinal implants carrying such bacteriorhodopsin films, as well as methods for making and using the same, for example, to treat retinal diseases and conditions.

Abstract: An artificial retinal system includes an external optical device having an image generator and a background light generator, and a retinal implant chip having a solar cell and a stimulus generator. The stimulus generator is disposed to receive a target image projected by the image generator and a background light provided by the background light generator, and receives the electrical power from the solar cell. The stimulus generator includes an image sensing stimulator operable to convert the target image into electrical stimuli, and a contrast enhancer for reducing effect of the background light on the electrical stimuli.

Abstract: The present invention is a visor for retinal stimulation of visually impaired subjects. The visor comprises a frame, an external coil, a camera and a mounting system. A connector allows the external coil to be positioned along a first direction. A sliding device allows the external coil to be positioned along a second direction. Positioning of the visor on a subject's nose allows the external coil to be positioned along a third direction. Positioning of the external coil along the first, second or third direction is useful to maximize coupling RF coupling between the external coil and an internal coil implanted on a subject wearing the visor.

Abstract: The present invention relates to biocompatible compositions for transplantation into a sub-retinal space of the human eye. The compositions include a biodegradable polyester film, preferably a polycaprolactone (PCL) film, and a layer of human retinal progenitor cells. The compositions of the invention can be used as scaffolds for the treatment a number of ocular diseases, including retinitis pigmentosa and age-related macular degeneration.

Abstract: A method for controlling heat dissipated from a prosthetic retinal device is described. A heat transfer device employs the Peltier heat transfer effect to cool the surface of the retinal device that faces the retina by dissipating/transferring collected heat away from the retina and towards the iris or front of the eye. According to one embodiment, a heat pump is formed in a second substrate on the retinal device. The heat pump is controlled by a temperature sense device that activates the heat pump, when a first predetermined temperature limit is exceeded. The temperature sense device deactivates the heat pump, when a temperature of the retinal device drops below a second predetermined temperature. According to another embodiment, a supply current of the retinal device may pass through the heat pump and a direction of heat transfer by the heat pump can be reversed, when the first predetermined temperature is exceeded.

Abstract: A system for generating artificial vision in a subject, comprising: an image capture means for capturing an image from a surrounding environment; an image processing means for processing the image and converting the image into an image signal; and a retinal implant or stimulation device (10) configured to be implanted within an eye of a patient and positioned on or adjacent the retina. The implant or stimulation device (10) comprises a substrate (11) and a plurality of light sources (12) arranged in an array on the substrate (11) for stimulating nerve cells of the retina, wherein each of the plurality of light sources (12) is configured to emit infrared radiation to stimulate one or more nerve cells in response to a respective stimulation signal derived from the image signal.

Abstract: Apparatus for use with an external non-visible light source is provided. The apparatus comprises an intraocular device configured for implantation in a human eye, and comprising an energy receiver. The energy receiver is configured to receive light emitted from the external non-visible light source, and extract energy from the emitted light for powering the intraocular device. The intraocular device is configured to regulate a parameter of operation of the intraocular device based on a modulation of the light emitted by the external non-visible light source and received by the energy receiver. Other embodiments are also described.

Abstract: The invention provides a retinal prosthetic method and device that mimics the responses of the retina to a broad range of stimuli, including natural stimuli. Ganglion cell firing patterns are generated in response to a stimulus using a set of encoders, interfaces, and transducers, where each transducer targets a single cell or a small number of cells. The conversion occurs on the same time scale as that carried out by the normal retina. In addition, aspects of the invention may be used with robotic or other mechanical devices, where processing of visual information is required. The encoders may be adjusted over time with aging or the progression of a disease.

Abstract: Apparatus is provided including an external device including, a mount, which is placed in front of an eye of a subject. A power source is coupled to the mount and emits energy toward the eye. An intraocular device is implanted entirely in the subject's eye, and includes a control unit, a plurality of stimulating electrodes, and an energy receiver, which receives the energy from the power source and generates a voltage drop in response. A plurality of photosensors detect photons and generate a signal in response. Driving circuitry is coupled to the energy receiver and to the photosensors, and drives the electrodes to apply electrical charges to a retina in response to the signals from the photosensors. The external device modulates the emitted energy, and the control unit demodulates the modulated energy to regulate an operation parameter of the intraocular device. Other embodiments are also described.

Abstract: The present invention comprises an implant for placing inside the eye such that the implant comes into contact with the interior tissue of the eye such that it conforms to the inner globe geometry of the eye. Implants of the present invention may also be used to alter the focal length of the eye thereby providing a treatment method for the correction of myopia and hyperopia. The device may consist of several possible configurations, an open mesh structure, a solid metal ring, a solid polymer shape, a mesh polymer shape or combination of these. The shape may be a curve, a sphere, a ring or a combination thereof that are specifically shaped to approximate a desired portion of the interior globe of the eye in order to treat myopia or hyperopia.

Abstract: An artificial retina that includes: (i) a substrate; (ii) a first layer, placed onto said substrate and including photovoltaic material portions separated by at least one insulating material portion; and (iii) a second layer, placed onto said first layer and including conductive material portions separated by at least one insulating material portion. In said artificial retina, the photovoltaic material includes a titanium dioxide semiconductor.

Abstract: The present invention is a system for mapping a high resolution image to a lower resolution electrode array and, by applying varying stimulus to neighboring electrodes, creating a perceived image greater in resolution than the electrode array. The invention is applicable to a wide range of neural stimulation devices including artificial vision and artificial hearing. By applying a sub-threshold stimulus to two neighboring electrodes where the sum of the stimuli is above the threshold of perception, a perception is created in neural tissue between the two electrodes. By adjusting the stimulus on neighboring electrodes, the location of stimulation can be altered. Further, noise can be applied to the stimulating electrode or its neighboring electrodes to reduce the threshold of stimulation.