Patent number 8709078 is assigned to
The following quote was obtained by the news editors from the background information supplied by the inventors: "For many patients suffering from retinal degenerative diseases such as advanced or age-related macular degeneration (AMD) and retinitis pigmentosa (RP) there has been little hope for maintaining vision. Every year, 700,000 new cases of AMD in the U.S. are diagnosed and 10% of those patients will become legally blind. There are presently no cures for these debilitating diseases, and, at best, current treatments only slow the disease progression. The overall social and economic impact of AMD and RP is immense and the importance of treating blindness is profound as this is a problem of significant scope and breadth. There is an unmet need to treat this ailment by developing a visual prosthetic with a large number (e.g., thousands) of stimulation channels to realistically restore sight using infrared light to stimulate the retinal nerves. Advanced macular degeneration and retinitis pigmentosa are both diseases that degrade vision in patients and eventually will lead to blindness.
"Researchers have artificially stimulated various parts of the human nervous system for many years as a way to restore lost or damaged neural function of various systems in the human body. Neuroprosthetic devices circumvent non-functioning physiological structures (hair cells in the ear, rods and cones in the eye) which would normally transduce an external stimulus (sound, light) into an action potential. Presently, there are numerous efforts underway to develop neuroprostheses to restore sight at various interventional anatomical locations: in the subretina, the epiretina, the optic nerve and in the visual cortex. These devices apply an electric current pulse to stimulate the neurons of the visual system which is inherently hindered by a lack of spatial selectivity. Electrical current spread leads to imprecise nerve stimulation and limits the ability of the neuroprosthesis to restore function. The limitation of spatial selectivity is based on fundamental physical principles of electrical stimulation. To date, after 20 years of development, electrical implants are just now hoping to make the jump to 64-channel systems from 16-channel systems. This is far less than the thousands of channels estimated to be needed for a good vision prosthetic. The technology is further limited by the fact that physical contact is required with tissue, which can lead to damage over time. Implantation of a complex powered device in very close proximity to sensitive neural tissue forms a significant drawback to this approach, making it impossible to update the technology without further risky surgeries.
"There have been rudimentary attempts to stimulate the retinal nerves with electrical signals, which are being conducted by various groups globally. For example, the Argus.TM. II implantable device, by
"U.S. Pat. No. 7,079,900 issued
"U.S. Pat. No. 7,914,842 issued
"Electrical stimulation represents a major challenge in developing implantable devices with long-term system performance while reducing their overall size.
"U.S. Pat. No. 7,908,010 issued
"Electrical stimulation, as described in the above devices and patents, is limited since the spread of electricity does not allow separate or independent stimulation of individual retinal nerve cells or even small-enough groups of nerve cells for sharp or clear vision. This electrical-stimulation technology is severely limited, as electricity spreads in human tissue and thus will severely limit the number of stimulation sites. Electrical stimulation thus greatly limits the number of sites that could be separately stimulated. Additionally, the electrical-stimulation approach will require implantation of a powered (e.g., an electrically powered) device, which has significant, difficult issues associated with obtaining power into the eye and using the power by devices in the eye.
"Other work is being done in the area of optogenetics wherein a virus is used to genetically sensitize nerve cells to certain wavelengths of light, e.g., PCT publication WO 2010/011404 A2 titled 'Vectors for Delivery of Light-Sensitive Proteins and Methods of Use,' which is incorporated herein by reference. This area may have some potential, however it will require significant development work, it involves injecting a virus into nerve tissue (which may have significant side effects and
"Materials that are compatible with the eye are described in U.S. Pat. No. 6,254,637 to
"Numerous digital light projection micro-electro-mechanical-system (MEMS) devices exist. For example, U.S. Pat. No. 4,566,935 issued to Hornbeck on
"As another MEMS display example, U.S. Pat. No. 7,776,631 issued to Miles on
"U.S. Pat. No. 7,177,081 issued to
"U.S. Pat. No. 4,720,189 issued
"U.S. Pat. No. 6,055,110 issued
"There remains a need in the art for an improved prosthesis and method for stimulating vision nerves to obtain a vision sensation that is more useful for the patient."
In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventors' summary information for this patent: "The present invention uses infrared nerve stimulation (INS) technology that uses infrared light to cause action potentials in nerve cells in the eye. In recent years, optical-stimulation technology has been developed to stimulate nerves. This INS technology can achieve much higher precision and selectivity of stimulation than using electrical current to trigger nerve action potentials. In some embodiments, the present technology uses pulsed, infrared lasers to excite the neural tissue next to the retina directly and without tissue damage. The advent of this technology represents a paradigm shift in artificial nerve stimulation because it allows a high degree of spatial selectivity of neural stimulation without the need for tissue contact.
"The present invention provides 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 AMD, RP, and other diseases. The invention utilizes infrared light to cause action potentials in the retinal nerves similar to those action potentials that result from rods and cones stimulated by visible light in healthy retinas. In a related invention by one of the inventors of the present invention, an eyeglass-mounted system is described that collects visual information and converts it into a stimulation pattern which is projected into the eye at an infrared wavelength with the purpose of causing an action potential in the retinal nerves with the purpose of recreating sight. As the infrared light stimulation wavelengths are normally strongly absorbed by the vitreous humor and tissues of the eye, in some embodiments the invention provides a pathway or 'image pipe' for transmitting a stimulation pattern of infrared nerve-stimulation light, from an external infrared-light-emitting stimulator array, through the eye and focusing the stimulation pattern of infrared light on the nerves of the retina, especially the macula and fovea. In some embodiments, the invention provides improved resolution down to a group of nerves, or even the individual nerve level, with sufficient energy density so as to cause desired action potentials in the targeted nerves.
"In some embodiments, a laser diode emitting light with a 1.87-micron wavelength stimulates nerves. This wavelength is important because devices capable of generating this wavelength are more available than longer mid-IR wavelengths. In some embodiments, laser-diode light of a 2.1-micron wavelength is used for nerve stimulation. Laser diodes that emit 2.1-micron-wavelength light are currently in research and would most likely work as well as other wavelengths, since this wavelength, when generated by a lamp-pumped solid-state laser, has been shown to be effective in stimulating nerves. In some embodiments, a laser-diode device (having one or more emitters) outputs light that is used for nerve stimulation, wherein the light has a wavelength of between about 1.5 microns and about 6 microns; in various embodiments, for example, the wavelength is in the far infrared at about 1.5 microns, or about 1.51 microns, about 1.52 microns, about 1.53 microns, about 1.54 microns, about 1.55 microns, about 1.56 microns, about 1.57 microns, about 1.58 microns, about 1.59 microns, about 1.6 microns, about 1.61 microns, about 1.62 microns, about 1.63 microns, about 1.64 microns, about 1.65 microns, about 1.66 microns, about 1.67 microns, about 1.68 microns, about 1.69 microns, about 1.7 microns, about 1.71 microns, about 1.72 microns, about 1.73 microns, about 1.74 microns, about 1.75 microns, about 1.76 microns, about 1.77 microns, about 1.78 microns, about 1.79 microns, about 1.8 microns, about 1.81 microns, about 1.82 microns, about 1.83 microns, about 1.84 microns, about 1.85 microns, about 1.86 microns, about 1.87 microns, about 1.88 microns, about 1.89 microns, about 1.9 microns, about 1.91 microns, about 1.92 microns, about 1.93 microns, about 1.94 microns, about 1.95 microns, about 1.96 microns, about 1.97 microns, about 1.98 microns, about 1.99 microns, about 2.0 microns, about 2.01 microns, about 2.02 microns, about 2.03 microns, about 2.04 microns, about 2.05 microns, about 2.06 microns, about 2.07 microns, about 2.08 microns, about 2.09 microns, about 2.1 microns, about 2.11 microns, about 2.12 microns, about 2.13 microns, about 2.14 microns, about 2.15 microns, about 2.16 microns, about 2.17 microns, about 2.18 microns, about 2.19 microns, about 2.2 microns, about 2.21 microns, about 2.22 microns, about 2.23 microns, about 2.24 microns, about 2.25 microns, about 2.26 microns, about 2.27 microns, about 2.28 microns, about 2.29 microns, about 2.3 microns, about 2.31 microns, about 2.32 microns, about 2.33 microns, about 2.34 microns, about 2.35 microns, about 2.36 microns, about 2.37 microns, about 2.38 microns, about 2.39 microns, about 2.4 microns, about 2.5 microns, about 2.6 microns, about 2.7 microns, about 2.8 microns, about 2.9 microns, about 3 microns, about 3.1 microns, about 3.2 microns, about 3.3 microns, about 3.4 microns, about 3.5 microns, about 3.6 microns, about 3.7 microns, about 3.8 microns, about 3.9 microns, about 4 microns, about 4.1 microns, about 4.2 microns, about 4.3 microns, about 4.4 microns, about 4.5 microns, about 4.6 microns, about 4.7 microns, about 4.8 microns, about 4.9 microns, about 5 microns, about 5.1 microns, about 5.2 microns, about 5.3 microns, about 5.4 microns, about 5.5 microns, about 5.6 microns, about 5.7 microns, about 5.8 microns, about 5.9 microns, or about 6.0 microns, or, in other embodiments, in ranges between any two of the above values. In other embodiments, an LED having output wavelengths centered in one of these ranges is used as a source of light to stimulate nerves.
"In some embodiments, the implant includes a material which is both biocompatible in the eye and highly transmissive at the infrared stimulation wavelengths. In some embodiments, the implant includes optics that focus, collimate, and/or guide the stimulation light. In some embodiments, the implant is sewn, stapled, or otherwise secured at the sclera and/or sewn, stapled, or otherwise secured to those locations where the eye's natural lens is normally attached. In some embodiments, the implant is totally encapsulated within the eye, while in some other embodiments, the implant extends through the cornea and/or sclera. In some embodiments, the ocular implant uses materials and design features already used in artificial corneas and intraocular lenses, for example, such as described in U.S. Pat. No. 6,254,637 to
"In some embodiments, once surgically implanted in the eye, the ocular implant has no internal moving parts relative to the eyeball and no internal electrical parts. Thus, such an ocular implant requires no internal or external electrical-power source. Additionally, the ocular implant does not impede movement of the eyeball after surgical implantation. In some embodiments, the freedom of eye movement relative to the external stimulator light can help provide enhanced patient comfort and enhanced perceived image resolution.
"In some embodiments, the present invention provides a VCSEL array configured to output light pulses capable of optically stimulating neural tissue (e.g., cochlear nerve tissue, deep brain tissue, white brain matter tissue, gray brain matter tissue, spinal cord tissue, cardial nerve tissue, central nervous system nerve tissue, olfactory nerve tissue, optic nerve tissue, nerve bundles and the like). In some embodiments, the stimulating lights pulses have a wavelength that results in the appropriate penetration depth for effective stimulation of the tissue of interest without causing tissue damage (e.g., in some embodiments, the wavelength of stimulating light pulses is in the range of about 1.8 microns to about 2.2 microns, in some embodiments, the wavelength of stimulating light pulses is in the range of about 1.85 microns to about 2.0 microns, in some embodiments, the wavelength of stimulating light pulses is about 1.87 microns, in some other embodiments the wavelength of stimulating light pulses is in the range of about 4.0 microns to about 5.0 microns, in some other embodiments the wavelength of stimulating light pulses is in the range of about 4.2 microns to about 4.8 microns, in some other embodiments the wavelength of stimulating light pulses is in the range of about 4.4 microns to about 4.6 microns)."
URL and more information on this patent, see: Friend, Michael E.; Hu, Yongdan. Ocular Implant with Substantially Constant Retinal Spacing for Transmission of Nerve-Stimulation Light. U.S. Patent Number 8709078, filed
Keywords for this news article include: Biomedical and Dental Materials, Viruses, Virology, Prosthetics, Laser Diodes, Legal Issues, Nanotechnology, Plasma Etching, Medical Devices, Emerging Technologies, Biocompatible Materials,
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