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Comments on The Blind May See - In The Dark
A number of companies and research laboratories are working on optical prostheses; devices that are actually implanted in the eye of a person who is unable to see. Some allow a patient to see in the far-infrared. (Read
the complete story)
"Congratulations on briefly giving my fiancee false hope. He has a degenerative retinal disorder which means he is not so slowly going blind. A search found this tripe. Really funny. Sleep well."
( 5/12/2004 4:26:55 PM) |
"This story was not intended to be funny, or cute. It is about a real company that is using solid science to solve a real problem. This story was taken primarily from a reputable online magazine; however, it is true that this magazine is not a peer-reviewed medical journal. However, I checked out the company quoted as using far-infrared technology; they do have a website representing an incorporated business. The company is Advanced Medical Electronics Corporation. Their website includes full contact information, including the names, phone numbers and email addresses of people you can talk with in their company.
On my site, I have lots of fun with science fiction, which can be irreverent or serious at the whim of the writer. I think I'm usually pretty serious about science, though - and I don't joke about subjects like this."
(Bill Christensen 5/12/2004 7:53:40 PM) |
"Long splurb below on state of the art. Real hope here!
Microchip Implantation
by Dan Roberts
Updated April, 2004
Research is currently being conducted by several groups in the area of retinal microchip implantation. This is a report on the work being done by the Optobionics Company in Chicago, the Harvard-M.I.T. Retinal Implant Project, the Intraocular Retinal Prosthesis Group at the University of Southern California, and a cooperative effort between the Stanford University School of Medicine and the Kresge Eye Institute.
Optobionics
One is a company called Optobionics, located in Wheaton, Illinois, and owned by pediatric ophthalmologist and inventor Dr. Alan Chow and his brother, Vincent, an electrical engineer.
Microchips just three millimeters across holding 4,000 to 5,000 microscopic solar cells can be implanted into the back of the eye. When light strikes those solar cells, it is converted into electrical signals that travel through the optic nerve to the brain and are interpreted as an image. This piece of silicon can then act as a replacement for a malfunctioning retina. The replacement retina has a diameter of two millimeters, and is about half the thickness of a sheet of paper. The two-hour operation is done through an incision in the white part of the eye (the sclera), and the chip is inserted into a pocket beneath the retina.
The Chows originally tested their chip in blind animals and successfully produced visual sensations. Their device displays only black and white images and works best in well-lit rooms, but they hope that the addition of more solar cells on the chip will eventually improve the results. Much of this technology hinges upon the ability of the human eye to accept silicon chip implants, and six retinitis pigmentosa patients have undergone the procedure during the past year. Dr. Chow reports that, as yet, there has been no sign of rejection, infection, inflammation, or detachment, and that the patients (all affected by retinitis pigmentosa) are reporting improved vision.
A press release from Optobionics (May 2002) reported these positive results, and also that the chips seem to be stimulating remaining healthy cells. Initial expectations were to gain some light perception at the site of the implant, but improvement outside the implant areas is also being seen: something Dr. Chow calls a "rescue effect." His report was also presented at the 2002 meeting of the Association for Research in Vision and Ophthalmology (ARVO) in Ft. Lauderdale, Florida.
UPDATE: In a recently-published article ("The Artificial Silicon Retina Microchip for the Treatment of Vision Loss From Retinitis Pigmentosa," Alan Y. Chow, MD [et al], Arch Ophthalmol. 2004;122:460-469), Optobionics researchers reported on the progress of the six subjects since implantation of the chips. They wrote:
"During follow-up that ranged from 6 to 18 months, all ASRs functioned electrically. No patient showed signs of implant rejection, infection, inflammation, erosion, neovascularization, retinal detachment, or migration. Visual function improvements occurred in all patients and included unexpected improvements in retinal areas distant from the implant. Subjective improvements included improved perception of brightness, contrast, color, movement, shape, resolution, and visual field size."
They explain the improvement of cell function far from the implant site as "a possible generalized neurotrophic-type rescue effect on the damaged retina caused by the presence of the ASR [artificial silicone retina]," and emphasize that "a larger clinical trial is indicated to further evaluate the safety and efficacy of a subretinally implanted ASR."
Harvard-M.I.T. Retinal Implant Project
A retinal prosthesis is being developed by a group led by Dr. Joseph Rizzo, professor of ophthalmology at Harvard and co-director of the Harvard-M.I.T. Retinal Implant Project. Rather than being positioned near the photoreceptors, his research group's chip will be positioned near the ganglion cells, which send nerve impulses to the brain. The prototype uses a camera mounted on a pair of eyeglasses to capture and transmit a light image to the chip. The light and images are converted into electrical impulses, which are transmitted to the brain along the optic nerve. The camera could be replaced with a digital signal processor, which is currently being developed by Germany's Retina Implant Association.
Dr. Florian Gekeler of the University Eye Hospital in T=FCbingen, Germany, is part of a consortium working on subretinal implants. His work shows that light entering the eye would not be strong enough to power photocells to stimulate retinal neurons, so his device uses an infrared diode mounted in a lens frame to deliver the necessary amount of light.
Intraocular Retinal Prosthesis Group, University of Southern California
Dr. Mark S. Humayun, director of the intraocular prosthetic laboratory at the Wilmer Ophthalmological Institute at Johns Hopkins Hospital in Baltimore, agrees with Dr. Gekeler about the intensity of light required to stimulate the retina. To solve this problem, his group is using a small external camera to transmit an image to the implanted chip, which is positioned near the ganglion cell layer.
Dr. Humayun teamed with Eugene de Juan to form the Intraocular Retinal Prosthesis Group at Doheny Retina Institute at the University of Southern California. Humayun and de Juan conceived the original retinal prosthesis and then turned over further development to the Oak Ridge, Sandia, Argonne, and Los Alamos national laboratories, with each lab working on a different aspect of the electrode array/retina interface. This $9m collaborative effort also involves the University of Southern California (where the devices will be implanted to test their effectiveness), Second Sight in Santa Clarita, California (who will commercially produce the finished system), and North Carolina State University in Raleigh, North Carolina (where development of the in-situ medical electronics is taking place).
On September 5, 2002, researchers at Sandia Labs announced that they have developed the Multiple-unit Artificial Retinal Chipset (MARC). According to the company's press release, the chip "involves multiple components mounted both inside and outside the eye. A spectacle-mounted camera takes video that is then processed and transmitted into the eye by radio. There, a chip made from micro-machined silicon and protective coatings receives the signal and extracts data with which to stimulate the retinal nerves. Like a crystal radio set, it also extracts the power it needs to run from the radio signal, removing the need for any external wires or internal power pack." The camera will initially be mounted on a pair of goggles, with plans for eventually placing it on the cornea of the eye. The receiver will be placed directly on the retina.
By the year 2004, the research team hopes to have improved the chip from its current 10x10 pixel capability to the point where it will produce a 33x33 pixel image (over 1,000 points of light). This is enough to recognize faces and read text.
Sandia is receiving $400,000 each year for its part in the research, which is led by Wessendorf and co-inventors Murat Okandan, David Stein, and Michael Rightley. The entire project is funded by a $9 million grant from the Department of Energy's Office of Biological and Environmental Research. For more information on this project, see the Sandia Laboratory press release.
Dr. Humayun performed the first surgery in February 2002, and two more pre-selected patients will soon receive the implants. Once permanently implanted devices have been proven to be safe and tolerable in the long term, larger scale clinical trials will begin to test their effectiveness.
Retinal prostheses are showing promise as replacements for diseased photoreceptor cells, but the work is still in the earliest stages of experimentation and the results are still primitive, allowing the subject to see only areas of light and dark at this time. Still, the progress being made is significant, and probably the best hope so far of restoring at least a semblance of sight to the blind.
Stanford University School of Medicine and Kresge Eye Institute
Two researchers are working on a nerve interface system which will drip neurotransmitters onto the cells, rather than jolting them with impulses from electrical implants. Harvey Fishman, MD, PhD, director of the Ophthalmic Tissue Engineering Laboratory at Stanford University School of Medicine, and Raymond Iezzi, MD, assistant professor of ophthalmology at the Kresge Eye Institute, Wayne State University, Detroit, are hoping that this approach will lead to higher resolution artificial vision. By comparison, implanted electrode arrays use relatively large electrodes, which stimulate hundreds or thousands of cells at once to create images (electrophosphenes). As a result, the images are not well-defined, and the best acuity achieved so far is only 20/1800.
The device being developed by Drs. Fishman and Iezzi is expected to be more precise. It is a microchip with 50-nm-wide holes which drip chemicals to attract nerve endings (axons) from the bipolar cells. This restores the connection which is lost when the cone cells in the macula degenerate. Once the connection is restored, light signals can once again travel from the photoreceptors to the optic nerve.
Dr. Fishman is working on the nerve interface system, and Dr. Iezzi is developing the delivery system for the neurotransmitters. His approach is to cage neurotransmitters (such as glutamate) in molecules, inject them into the retina, and then expose the molecules to ultraviolet light. The light exposure would cause the molecule to break open and free the glutamate to make connection with the bipolar cells. The patient would carry his own supply of neurotransmitters, perhaps in a reservoir worn behind the ear.
Tests on animals for this new system are planned to begin by the year 2004.
"
(Stephen Thomas 5/13/2004 2:52:27 PM) |
"ITS NICE"
( 9/12/2005 2:04:38 AM) |
"soo cool! i got my rept done in five minutes instead of five hundred minutes!"
(heygirl 12/10/2005 12:57:58 PM) |
"Totally Blind from retinitis pigmentosis. Can you be of some help"
(Louis Scarpino 12/29/2005 11:05:27 PM) |
"this thing does not help me! with finding out the definition of the eye stuff!"
(whatever 2/26/2006 8:58:51 PM) |
"sounds more like the visor that jorde le forge wears on star trek next generation"
( 5/22/2006 7:38:51 PM) |
"I think that is amazing....it is so cool to see how science can help someone that would ordinarily be out of luck.....love the article"
(Spencer 5/23/2006 7:57:43 AM) |
Get more information on The Blind May See - In The Dark
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