retinitispigmentosa
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Soft, synthetic retinas may offer a better implant solution
Scientists have been trying to replace retinas in otherwise healthy eyes to help people suffering from diseases like retinitis pigmentosa. Unfortunately, earlier efforts were only able to use rigid, hard materials, which are very different from the natural retina. A researcher at Oxford University, however, has created a synthetic retina made of biological materials to better match natural human tissues. The study, titled "Light-Patterned Current Generation in a Droplet Bilayer Array" was published this April in Scientific Reports.
Blind woman may see thanks to gene therapy and light
Optogenetics, or mixing gene therapy with light treatments, is finally getting a proper field test: doctors have given a blind Texas woman the first optogenetics-based therapy in hopes of restoring some of the vision lost to a degenerative retina disease. The procedure injected her eye with viruses containing DNA from light-sensitive algae, letting them mimic the eye's rods and cones by generating electricity whenever they're subjected to light. The patient won't get full vision even if the therapy is a runaway success, but it could be enough to let her know when there's nearby activity.
Algae DNA could help the blind see in upcoming trials
Optogenetics is one of the greatest achievements in gene splicing over the last decade, as it has helped researchers see how the brain works in animals by making neurons react to light. For the first time, however, the technique will be tried on a human subjects to help legally blind folks see for the first time. Using research developed by Wayne State University scientist Zhuo-Hua Pan, a company called RestroSense will inject a virus doped with light-sensitive algae DNA directly into a patient's eyes. So far, the only successful attempts at restoring vision in humans has come using the Argus II implant.
Microchip implant lets blind patients see shapes, skip the prosthetic
An eye-implanted chip from Retina Implant has restored patients' ability to discern light during its latest trial, according to German researchers. The device works in a similar fashion to the newly FDA-approved Argus II retinal prosthesis to return limited vision in patients with photoreceptor cell diseases like retinitis pigmentosa. Unlike that system, however, light is picked up via 1,500 pixels on a retinal implant instead of an eyeglass-mounted camera. The signal is boosted by a coil implanted in skin behind the ear and sent back to so-called bipolar cells still active on the retina, which in turn send an image to the brain through regular neural circuits. A small battery mounted behind the ear -- the only external sign of the device -- contains controls for brightness and contrast. The recent trial let 8 out of 9 patients see in varying degrees, with three in the study even able to read letters and see the faces of family members. Given that the Argus II finally crossed the FDA's bionic eye barrier, hopefully we won't have to wait nearly as long for research like this to become a product.
FDA clears Argus II 'bionic eye' for sale in the US (video)
Those in the US suffering from blindness due to retinis pigmentosa (RP) will now be able to regain some vision bionically for the first time ever, thanks to Second Sight's Argus II retinal prosthesis. The device was just approved by the FDA for sale stateside after surmounting the same hurdle in Europe almost two years ago -- though it was first launched long, long before that. RP is a rare genetic disease that inflicts 100,000 or so Americans, destroying photoreceptors in the eye while leaving other cells intact. By implanting a device on the retina that receives a signal from the eyeglass-mounted camera, those cells can be stimulated as if receiving light, causing them to transmit an image to the brain. Due to the limited number of electrodes, patients would only be able to discern light or dark, but most have reported better functionality with the device -- being able to make out the shape of a curb while walking, or discerning between light, grey or dark colored socks, for instance. The Argus II has been certified by the FDA for "humanitarian use," meaning there's "reasonable assurance" that it's safe, and should start popping up in specialized clinics by the end of the year. [Photo credit: Associated Press]
Subretinal implant successfully tested on humans, makes blind narrowly see
How many scientists does it take to properly install a lightbulb? When that lightbulb is an implant that stimulates retinal photoreceptors to restore one's sight, quite a few -- even if they disagree whether said implant should be placed on top of the retina (requiring glasses to supply power and video feed) or underneath, using photocells to channel natural sunlight. Now, a German firm dubbed Retina Implant has scored a big win for the subretinal solution with a three-millimeter, 1,500 pixel microchip that gives patients a 12 degree field of view. Conducting human trials with 11 patients suffering from retinitis pigmentosa, the company successfully performed operations on seven, with one even managing to distinguish between similar objects (knife, fork, spoon) and perform very basic reading. Though usual disclaimers apply -- the tech is still a long way off, it only works on folks who've slowly lost their vision, etc. -- this seems like a step in the right direction, and at least one man now knows which direction that is.
UPenn scientists create replacement retina on a chip
Scientists at the University of Pennsylvania have developed a new silicon chip that could be "embedded directly into the eye and connected to the nerves that carry signals to the brain's visual cortex," reports New Scientist. The chip aims to help people suffering from retinitis pigmentosa, which is the gradual death of one's retinal cells, those really useful bits of organic matter that convert light into nerve impulses for the brain to process. Previous attempts at solving this biological conundrum have often gone the route of using a video camera usually connected to a tiny computer to process the signal, which is then attached to the optic nerve. If Penn's research works, it would let this chip be directly implanted into the eye -- with a direct connection to the optic nerve -- removing the need for an external camera. Even better, this new version also mimics the way a healthy retina adjusts to light intensity, contrast, and even movement. The next step is to reducing the size and power consumption of the chip before clinical trials can get going.[Via New Scientist]
