Retinal Microstimulation

US5109844

A method for stimulating a retinal ganglion cell in a retina without penetrating the retinal basement membrane at the surface of the retina comprises: (a) positioning a ganglion cell stimulating electrode on or above the retinal basement membrane; (b) providing a ground electrode in operative association with the ganglion cell stimulating electrode, with the ground electrode positioned on or above the retinal basement membrane and positioned for capturing electric current produced by the stimulating electrode; and (c) applying a voltage to said stimulating electrode sufficient to produce an electric current which penetrates the retina and produces an action potential in a retinal ganglion cell. Apparatus for practicing the foregoing method is also disclosed.

5/05/1992

Visual Prosthesis and Method of Using Same

US5935155

A visual prosthesis comprises a camera for perceiving a visual image and generating a visual signal output, retinal tissue stimulation circuitry adapted to be operatively attached to the user's retina, and wireless communication circuitry for transmitting the visual signal output to the retinal tissue stimulation circuitry within the eye. To generate the visual signal output the camera converts a visual image to electrical impulses which are sampled to selecting an image at a given point in time. The sampled image signal is then encoded to allow a pixelized display of it. This signal then is used to modulate a radio frequency carrier signal. A tuned coil pair having a primary and a secondary coil are used to transmit and receive the RF modulated visual signal which is then demodulated within the eye. The retinal stimulation circuitry includes a decoder for decoding the visual signal output into a plurality of individual stimulation control signals which are used by current generation circuitry to generate stimulation current signals to be used by an electrode array having a plurality of electrodes forming a matrix. The intraocular components are powered from energy extracted from the transmitted visual signal. The electrode array is attached to the retina via tacks, magnets, or adhesive.

8/10/1999

Method for Preferential Outer Retinal Stimulation

US5944747

A method of focused phosphene generation through deeper intermediate retinal cellular electrical stimulation to the exclusion of direct ganglion cellular electrical stimulation comprises the steps of: a) positioning a stimulating electrode in the vicinity of retinal tissue; and b) applying a long duration stimulation signal to the electrode such that deeper intermediate retinal cells are preferentially stimulated over the retinal ganglion cells and proximal overlying surface axons. The long duration stimulation signal is preferably a biphasic signal having a negative and a positive phase pulse which is applied in cathodic fashion. To preferentially stimulate the deeper intermediate retinal elements the duration of the long duration stimulation signal is greater than 0.5 millisecond per phase pulse, and preferably equal to or longer than 2 millisecond per phase pulse. The biphasic signal is preferably adjusted to simulate a monophasic signal by adjusting the magnitude of the negative pulse in relation to positive pulse, and by adjusting the duration of the positive pulse in relation to the negative pulse to maintain approximately net zero charge introduction. Preferably, the ratio of the negative pulse to the positive pulse is approximately 10:1 or greater.

8/31/1999

Device and Method for Manual Retinal Vein Catheterization

WO0149352A2

A microcatheter system that allows for vascular infusion into retinal veins for extended periods of time. The microcatheter system includes a flexible cannula that is inserted into the retinal vein lumen and that remains stably within the retinal vein lumen without being held by a robot, micromanipulator or similar holding devices. The microcatheter system is particularly suitable for the treatment of retinal venous occlusive disease.

7/12/2001

Devices for Intraocular Drug Delivery

US2002026176A1

A therapeutic agent delivery device that can allows is particularly suitable for delivery of a therapeutic agent to limited access regions, such as the posterior chamber of the eye and inner ear. Preferred devices of the invention are minimally invasive, refillable and may be easily fixed to the treatment area. Preferred delivery devices of the invention also include those that comprise a non-linear shaped body member body housing one or more substances and a delivery mechanism for the sustained delivery of the one or more substances from the non-linear shaped body member to the patient.substance to be delivered, and delivery mechanism for delivering the substance

2/28/2002

Visual Prosthesis Including Enhanced Receiving and Stimulating Portion

US2002095193A1

A visual prosthesis including an enhanced receiving and stimulating portion for electrically stimulating retinal tissue to present an apparent image to a user. The prosthesis includes an extraocular camera which responds to a real image to generate a real image signal. The real image signal is coupled, e.g., RF coupling, from an extraocular primary coil to a secondary coil. The secondary coil is preferably affixed within the vitreous body of the user's eye positioned for good signal coupling to the primary coil and arranged to be in good thermal contact with the vitreous body which acts as a heat sink. A hermetically sealed housing containing signal processing circuitry is also preferably placed in the vitreous body to assure efficient heat transfer away from the housing. The circuitry is electrically connected to the secondary coil and responds to an output signal therefrom to produce an apparent image signal for driving an electrode array. The electrode array is configured to electrically stimulate the eye's retinal tissue to enable a user to perceive an apparent image.

7/18/2002

Soft tip Cannula and Methods for use Thereof

US2002121281A1

A surgical device having a body portion that is gripped by a user, the body portion having a distal end equipped with a soft tip and the proximal end optionally connected to an external vacuum or gas/air source. The surgical device is particularly suitable for use in ophthalmic surgical procedures to remove fluid from the eye or introduce gas/air into the eye. The soft tip is fabricated to protect the delicate tissues if the eye and is further modified so as to enhance a user's visibility of the device in the surgical field.

9/5/2002

Modulating Photoreactivity in a Cell

WO03001249A2

Modulating photoreactivity in a cell, involves providing a cell, and incorporating an isolated trigger on the surface or in the membrane of the cell.

1/03/2003

Flexible Electrode Array for Artificial Vision

US2003097165A1

An image is captured or otherwise converted into a signal in an artificial vision system. The signal is transmitted to the retina utilizing an implant. The implant consists of a polymer substrate made of a compliant material such as poly(dimethylsiloxane) or PDMS. The polymer substrate is conformable to the shape of the retina. Electrodes and conductive leads are embedded in the polymer substrate. The conductive leads and the electrodes transmit the signal representing the image to the cells in the retina. The signal representing the image stimulates cells in the retina.

5/22/2003

Variable Pitch Electrode Array

US2003187491A1

The present invention is an implantable electrode array having electrodes with variable pitch and variable size. Electrode arrays of the prior art provide electrodes with a common spacing and size. However, this is not how the human body is arranged. As an example, the retina has closely spaced retinal receptors near the fovea. Those receptors are spaced farther apart, farther away from the fovea. Further, the amount of electrical current required to stimulate the perception of light increases with distance from the fovea. Hence, larger electrodes are required to transfer the necessary current farther away from the fovea.

10/02/2003

Reinforcement Elements In a Silicone Electrode Array

WO04011083A1

An electronic device for connection to tissue comprises a substrate composed of silicone that has the ability to conform to various shapes of tissue. Electrodes are embedded in the substrate for contacting the tissue. Reinforcement structural elements are formed in the substrate.

2/05/2004

Permanent Retinal Implant Device

US2004106966A1

The retinal prosthesis test device is comprised of a thin wafer of glass made from nanochannel glass (NGC) with very small channels perpendicular to the plane of the wafer filled with an electrical conductor forming microwires. One surface of the glass is ground to a spherical shape consistent with the radius of curvature of the inside of the retina. The NGC is hybridized to a silicon de-multiplexer and a video image is serially input to a narrow, flexible micro-cable and read into a 2-D array of unit cells in a pixel-by-pixel manner which samples the analog video input and stores the value as a charge on a MOS capacitor. After all unit cells have been loaded with the pixel values for the current frame, a biphasic pulse is sent to each unit cell which modulates the pulse in proportion to the pixel value stored therein. Because the biphasic pulses flow in parallel to each unit cell from a global external connection, the adjacent retinal neurons are all stimulated simultaneously, analogous to image photons stimulating photoreceptors in a normal retina. A permanent retinal implant device uses a NGC array hybridized to a silicon chip, the image is simultaneously generated within each cell through a photon-to-electron conversion using a silicon photodiode. The photons propagate directly through into the backside of the device. Electrical power and any control signals are transmitted through an inductively driven coil or antenna on the chip. The device collects the charge in storage capacitors via the photonto-electron conversion process, stimulates the neural tissue with biphasic pulses in proportion to the stored charges, and resets the storage capacitors to repeat the process. array hybridized to 2D array of unit cells with indium bumps

6/03/2004

Optically Powered and Optically Data-transmitting Wireless Intraocular Pressure Sensor Device

US2004116794A1

An optically powered and optically data-transmitting wireless intraocular pressure sensor device for detecting excessive intraocular pressure above a predetermined threshold pressure, comprising a pressure switch that is sized and configured to be placed in an eye, wherein said pressure switch is activated when the intraocular pressure is higher than the predetermined threshold pressure. In one embodiment, the pressure sensor device is a micro electromechanical system.

6/17/2004

Devices for Intraocular Drug Delivery

US2004133155A1

An therapeutic agent delivery device that can allows is particularly suitable for delivery of a therapeutic agent to limited access regions, such as the posterior chamber of the eye and inner ear. Preferred devices of the invention are minimally invasive, refillable and may be easily fixed to the treatment area. Preferred delivery devices of the invention also include those that comprise a non-linear shaped body member body housing one or more substances and a delivery mechanism for the sustained delivery of the one or more substances from the non-linear shaped body member to the patient.

7/08/2004

Reservoirs with Subretinal Cannula for Subretinal Drug Delivery

WO04066871A2

Subretinal delivery device for use in treating ocular conditions, e.g. retinal/choroidal disorders, comprises cannula extending from reservoir for containing agent, which is released through the cannula

8/12/2004

Microelectronic Stimulator Array for Stimulating Nerve Tissue

US2004172100A1

The retinal prosthesis test device is comprised of a thin wafer of glass made from nanochannel glass (NGC) with very small channels perpendicular to the plane of the wafer filled with an electrical conductor forming microwires. One surface of the glass is ground to a spherical shape consistent with the radius of curvature of the inside of the retina. The NGC is hybridized to a silicon de-multiplexer and a video image is serially input to a narrow, flexible micro-cable and read into a 2-D array of unit cells in a pixel-by-pixel manner which samples the analog video input and stores the value as a charge on a MOS capacitor. After all unit cells have been loaded with the pixel values for the current frame, a biphasic pulse is sent to each unit cell which modulates the pulse in proportion to the pixel value stored therein. Because the biphasic pulses flow in parallel to each unit cell from a global external connection, the adjacent retinal neurons are all stimulated simultaneously, analogous to image photons stimulating photoreceptors in a normal retina. A permanent retinal implant device uses a NGC array hybridized to a silicon chip, the image is simultaneously generated within each cell through a photon-to-electron conversion using a silicon photodiode. The photons propagate directly through into the backside of the device. Electrical power and any control signals are transmitted through an inductively driven coil or antenna on the chip. The device collects the charge in storage capacitors via the photon-to-electron conversion process, stimulates the neural tissue with biphasic pulses in proportion to the stored charges, and resets the storage capacitors to repeat the process.

9/02/2004

Method and System for Training a Visual Prosthesis

US2004236389A1

A method for training a visual prosthesis includes presenting a non-visual reference stimulus corresponding to a reference image to a visual prosthesis patient. The visual prosthesis including a plurality of electrodes. Training data sets are generated by presenting a series of stimulation patterns to the patient through the visual prosthesis. Each stimulation pattern in the series, after the first, is determined at least in part on a previous subjective patient selection of a preferred stimulation pattern among stimulation patterns previously presented in the series and a fitness function optimization algorithm. The presented stimulation patterns and the selections of the patient are stored and presented to a neural network off-line to determine a vision solution.

11/25/2004

Soft Tip Cannula and Methods for use Thereof

US2005033272A1

A surgical device having a body portion that is gripped by a user, the body portion having a distal end equipped with a soft tip and the proximal end optionally connected to an external vacuum or gas/air source. The surgical device is particularly suitable for use in ophthalmic surgical procedures to remove fluid from the eye or introduce gas/air into the eye. The soft tip is fabricated to protect the delicate tissues if the eye and is further modified so as to enhance a user's visibility of the device in the surgical field.

2/10/2005

Devices for Intraocular Drug Deliver

US2005059956A1

An therapeutic agent delivery device that can allows is particularly suitable for delivery of a therapeutic agent to limited access regions, such as the posterior chamber of the eye and inner ear. Preferred devices of the invention are minimally invasive, refillable and may be easily fixed to the treatment area. Preferred delivery devices of the invention also include those that comprise a non-linear shaped body member body housing one or more substances and a delivery mechanism for the sustained delivery of the one or more substances from the non-linear shaped body member to the patient.

3/17/2005