News Column

Patent Issued for Video Processing Unit for a Visual Prosthetic Apparatus

August 19, 2014



By a News Reporter-Staff News Editor at Life Science Weekly -- A patent by the inventors McClure, Kelly H. (Simi Valley, CA); Roy, Arup (Valencia, CA); Castro, Richard Agustin (Pasadena, CA); Yadav, Sumit (Los Angles, CA); Dai, Rongqing (Valencia, CA); Greenberg, Robert J. (Los Angeles, CA); Chang, Da-Yu (Rowland Heights, CA); Wu, Xiaofan (Saugus, CA); Loftin, Scott (Rosamond, CA); McCord, Susan (Santa Monica, CA), filed on November 7, 2007, was published online on August 5, 2014, according to news reporting originating from Alexandria, Virginia, by NewsRx correspondents (see also Second Sight Medical Products, Inc.).

Patent number 8798756 is assigned to Second Sight Medical Products, Inc. (Sylmar, CA).

The following quote was obtained by the news editors from the background information supplied by the inventors: "In 1755 LeRoy passed the discharge of a Leyden jar through the orbit of a man who was blind from cataract and the patient saw 'flames passing rapidly downwards.' Ever since, there has been a fascination with electrically elicited visual perception. The general concept of electrical stimulation of retinal cells to produce these flashes of light or phosphenes has been known for quite some time. Based on these general principles, some early attempts at devising a prosthesis for aiding the visually impaired have included attaching electrodes to the head or eyelids of patients. While some of these early attempts met with some limited success, these early prosthetic devices were large, bulky and could not produce adequate simulated vision to truly aid the visually impaired.

"In the early 1930's, Foerster investigated the effect of electrically stimulating the exposed occipital pole of one cerebral hemisphere. He found that, when a point at the extreme occipital pole was stimulated, the patient perceived a small spot of light directly in front and motionless (a phosphene). Subsequently, Brindley and Lewin (1968) thoroughly studied electrical stimulation of the human occipital (visual) cortex. By varying the stimulation parameters, these investigators described in detail the location of the phosphenes produced relative to the specific region of the occipital cortex stimulated. These experiments demonstrated: (1) the consistent shape and position of phosphenes; (2) that increased stimulation pulse duration made phosphenes brighter; and (3) that there was no detectable interaction between neighboring electrodes which were as close as 2.4 mm apart.

"As intraocular surgical techniques have advanced, it has become possible to apply stimulation on small groups and even on individual retinal cells to generate focused phosphenes through devices implanted within the eye itself. This has sparked renewed interest in developing methods and apparatuses to aid the visually impaired. Specifically, great effort has been expended in the area of intraocular visual prosthesis devices in an effort to restore vision in cases where blindness is caused by photoreceptor degenerative retinal diseases such as retinitis pigmentosa and age related macular degeneration which affect millions of people worldwide.

"Neural tissue can be artificially stimulated and activated by prosthetic devices that pass pulses of electrical current through electrodes on such a device. The passage of current causes changes in electrical potentials across visual neuronal membranes, which can initiate visual neuron action potentials, which are the means of information transfer in the nervous system.

"Based on this mechanism, it is possible to input information into the nervous system by coding the information as a sequence of electrical pulses which are relayed to the nervous system via the prosthetic device. In this way, it is possible to provide artificial sensations including vision.

"One typical application of neural tissue stimulation is in the rehabilitation of the blind. Some forms of blindness involve selective loss of the light sensitive transducers of the retina. Other retinal neurons remain viable, however, and may be activated in the manner described above by placement of a prosthetic electrode device on the inner (toward the vitreous) retinal surface (epiretial). This placement must be mechanically stable, minimize the distance between the device electrodes and the visual neurons, and avoid undue compression of the visual neurons.

"In 1986, Bullara (U.S. Pat. No. 4,573,481) patented an electrode assembly for surgical implantation on a nerve. The matrix was silicone with embedded iridium electrodes. The assembly fit around a nerve to stimulate it.

"Dawson and Radtke stimulated cat's retina by direct electrical stimulation of the retinal ganglion cell layer. These experimenters placed nine and then fourteen electrodes upon the inner retinal layer (i.e., primarily the ganglion cell layer) of two cats. Their experiments suggested that electrical stimulation of the retina with 30 to 100 uA current resulted in visual cortical responses. These experiments were carried out with needle-shaped electrodes that penetrated the surface of the retina (see also U.S. Pat. No. 4,628,933 to Michelson).

"The Michelson '933 apparatus includes an array of photosensitive devices on its surface that are connected to a plurality of electrodes positioned on the opposite surface of the device to stimulate the retina. These electrodes are disposed to form an array similar to a 'bed of nails' having conductors which impinge directly on the retina to stimulate the retinal cells. U.S. Pat. No. 4,837,049 to Byers describes spike electrodes for neural stimulation. Each spike electrode pierces neural tissue for better electrical contact. U.S. Pat. No. 5,215,088 to Norman describes an array of spike electrodes for cortical stimulation. Each spike pierces cortical tissue for better electrical contact.

"The art of implanting an intraocular prosthetic device to electrically stimulate the retina was advanced with the introduction of retinal tacks in retinal surgery. De Juan, et al. at Duke University Eye Center inserted retinal tacks into retinas in an effort to reattach retinas that had detached from the underlying choroid, which is the source of blood supply for the outer retina and thus the photoreceptors. See, e.g., E. de Juan, et al., 99 Am. J. Opthalmol. 272 (1985). These retinal tacks have proved to be biocompatible and remain embedded in the retina, and choroid/sclera, effectively pinning the retina against the choroid and the posterior aspects of the globe. Retinal tacks are one way to attach a retinal array to the retina. U.S. Pat. No. 5,109,844 to de Juan describes a flat electrode array placed against the retina for visual stimulation. U.S. Pat. No. 5,935,155 to Humayun describes a visual prosthesis for use with the flat retinal array described in de Juan."

In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventors' summary information for this patent: "According to a first aspect, a visual prosthesis apparatus is disclosed, a visual prosthesis apparatus comprising: a video capture device for capturing a video image; a video processing unit associated with the video capture device, the video processing unit configured to convert the video image to stimulation patterns; and a retinal stimulation system configured to stimulate neural tissue in a subject's eye based on the stimulation patterns, wherein the video processing unit is configured to be powered on after a first time interval upon activation of a power button, wherein the video processing unit is configured to be powered off after a second time interval upon activation of a power button.

"According to a second aspect, a visual prosthesis apparatus is disclosed, a visual prosthesis apparatus comprising: a video capture device for capturing a video image; a video processing unit associated with the video capture device, the video processing unit comprising a video processor for converting the video image to a digital video stream; a memory for storing the digital video stream; a video preprocessor data interface for forming stimulation patterns based on the stored digital video stream; and a retinal stimulation system configured to stimulate neural tissue in a subject's eye based on the stimulation patterns.

"According to a third aspect, a video processing unit is disclosed, the video processing unit configured to convert a video image to stimulation patterns for stimulating neural tissue in a subject's eye and comprising a power button, wherein the video processing unit is configured to be powered on after a first time interval upon activation of a power button, wherein the video processing unit is configured to be powered off after a second time interval upon activation of a power button.

"According to a fourth aspect, a video processing unit configured to convert a video image to stimulation patterns for stimulating neural tissue in a subject's eye is disclosed, the video processing unit comprising a video processor for converting a video image to a digital video stream; a memory for storing the digital video stream; and a video preprocessor data interface for forming stimulation patterns based on the stored digital video stream.

"According to a fifth aspect, a method for providing artificial vision is disclosed, the method comprising powering a video processing unit a first amount of time after a power button is activated; capturing a video image; converting the video image to stimulation patterns using the video processing unit; and stimulating neural tissue in a subject's eye based on the stimulation patterns.

"According to a sixth aspect, a method for providing artificial vision is disclosed, the method comprising capturing a video image; converting the video image to a digital video stream; storing the digital video stream; forming stimulation patterns based on the stored digital video stream; and stimulating neural tissue in a subject's eye based on the stimulation patterns.

"According to a seventh aspect, a visual prosthesis apparatus is disclosed, the visual prosthesis apparatus comprising: a video capture device for capturing a video image; a video processing unit associated with the video capture device, the video processing unit configured to convert the video image to stimulation patterns; and a retinal stimulation system configured to stimulate neural tissue in a subject's eye based on the stimulation patterns, wherein the video processing unit is configured to be powered on after a first time interval upon activation of a power button, wherein the video processing unit is configured to be powered off after a second time interval upon activation of a power button, wherein the video processing unit is disposed on a visor.

"According to a eight aspect, a visual prosthesis apparatus is disclosed, the video prosthesis apparatus comprising a video capture device for capturing a video image; a video processing unit associated with the video capture device, the video processing unit comprising a video processor for converting the video image to a digital video stream; a memory for storing the digital video stream; a video preprocessor data interface for forming stimulation patterns based on the stored digital video stream; and a retinal stimulation system configured to stimulate neural tissue in a subject's eye based on the stimulation patterns, wherein the video processing unit is disposed on a visor.

"According to a ninth aspect, a video processing unit is disclosed, the video processing unit configured to convert a video image to stimulation patterns for stimulating neural tissue in a subject's eye and comprising a power button, wherein the video processing unit is configured to be powered on after a first time interval upon activation of a power button, wherein the video processing unit is configured to be powered off after a second time interval upon activation of a power button, wherein the video processing unit is disposed on a visor.

"Further embodiments are shown in the specification, drawings and claims of the present application."

URL and more information on this patent, see: McClure, Kelly H.; Roy, Arup; Castro, Richard Agustin; Yadav, Sumit; Dai, Rongqing; Greenberg, Robert J.; Chang, Da-Yu; Wu, Xiaofan; Loftin, Scott; McCord, Susan. Video Processing Unit for a Visual Prosthetic Apparatus. U.S. Patent Number 8798756, filed November 7, 2007, and published online on August 5, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8798756.PN.&OS=PN/8798756RS=PN/8798756

Keywords for this news article include: Second Sight Medical Products Inc.

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Source: Life Science Weekly


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