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Thread: Blindness & Restoring Sight Research

  1. Icon6 Blindness & Restoring Sight Research

    But won't people look funny with mouse eyes?...

    Mice eye research raises hopes of cure for blindness
    Fri, Apr 20, 2012 - Scientists have improved the eyesight of mice born with night blindness by injecting healthy light-sensitive cells into their retinas. The work is the first demonstration that cell transplants can restore useful vision.
    Injections of the cells produced only modest changes in the animals’ eyesight, but the results have raised hopes that a similar therapy might one day help reverse some forms of human blindness, such as age-related macular degeneration, the most common cause of blindness, which affects up to 15 percent of people over 75. In the study, researchers at University College London’s Institute of Ophthalmology injected the precursors of light-sensitive cells — taken from newborn mice — into the eyes of adult mice with a genetic form of night blindness.

    Each jab delivered about 200,000 photoreceptor cells, of which 20,000 to 30,000 attached to the animals’ retinas and made working neural connections. Although the newly wired-up cells accounted for less than 1 percent of the rods in the retinas, the mice still showed an improvement in eyesight. “This is the first proof of principle for restoring vision by transplanting photoreceptor cells. Until now it’s been assumed, and hoped for, but not actually proven,” said Rachael Pearson, a neuroscientist at the institute, who led the study published in Nature. The retina contains two broad kinds of light sensitive cells, rods and cones. In mice and humans, more than 95 percent are rods. These work well in the dark and are good at spotting movement, but see the world in black and white. Cones are less numerous, but give a sharp, color view of the world in good lighting conditions.

    The scientists used only rods in the latest experiments, as they are easier to transplant, but they are now pushing ahead with plans to repeat the work with cone cells. In humans, about 200,000 cones are concentrated in a small, central part of the retina called the fovea. In a series of tests, including one that measured the animals’ ability to distinguish varying shades of gray, and another that timed how quickly mice found a submerged platform in a water tank under low lighting conditions, the animals’ vision was 10 to 20 percent as good as healthy mice. The animals that performed best had the most newly connected rod cells.

    Untreated, the mice were effectively blind in dim light. “Now we’ve discovered we can restore vision, it gives us impetus to go on and make the process better,” said Robin Ali, a senior author on the study. Scientists need to clear several major hurdles before considering rod and cone transplants for human clinical trials. One crucial step is to make suitable donor cells, either from established stores of embryonic stem cells, or by converting patients’ skin cells into photoreceptor cells. Another question is whether donor cells last for long when transplanted, or are rejected by the body’s immune system.

    Last edited by waltky; Apr 20 2012 at 12:42 AM.

  2. Cool

    Three blind mice can now see how they run...

    Blind Mice Given Sight After Device Cracks Retinal Code
    Aug 13, 2012 - Blind mice had their vision restored with a device that helped diseased retinas send signals to the brain, according to a study that may lead to new prosthetic technology for millions of sight-impaired people.
    Current devices are limited in the aid they provide to people with degenerative diseases of the retina, the part of the eye that converts light into electrical impulses to the brain. In research described today in the Proceedings of the National Academy of Sciences, scientists cracked the code the retina uses to communicate with the brain. The technology moves prosthetics beyond bright light and high-contrast recognition and may be adopted for human use within a year or two, said Sheila Nirenberg, a neuroscientist at Weill Cornell Medical College in New York and the study’s lead author. “What this shows is that we have the essential ingredients to make a very effective prosthetic,” Nirenberg said. Researchers haven’t yet tested the approach on humans, though have assembled the code for monkeys, she said.

    Once the researchers determined the code the mouse retina used to communicate with the brain, they were able to mimic it with electric-signal sending glasses, Nirenberg said. Previous prosthetics have used less-specific stimulation and proved inherently limited as a result, she said. About 20 million people worldwide are blind or facing blindness due to retinal degenerative diseases, such as macular degeneration and retinitis pigmentosa. The disorders cause a progressive loss of the retina’s input cells, or photoreceptors.

    Visual Equations

    Nirenberg and co-author Chethan Pandarinath first monitored healthy eyes to determine the set of equations that translate light received by the retina into something the brain can understand. Then, they used special glasses to create a similar code and deliver it to the eye, which they had injected with a virus containing light-sensitive cells. The cells received the code and fired electric impulses, which the brain could interpret as images. Nirenberg’s research “is basically giving vision back to a system that doesn’t work,” said Aude Oliva, a principal investigator at the Massachusetts Institute of Technology’s Computer Science and Artificial Intelligence Laboratory in Cambridge, Massachusetts, who wasn’t involved in the research. “I’ve never seen, and other people have never seen, this quality.”

    No foreseeable barriers should stop the movement into humans now that the technology has been created, Oliva said. Nirenberg said that if researchers can come up with adequate cash to fund clinical trials, she hopes to soon adapt the technology. Macular degeneration is the leading cause of blindness in people older than 55 in the western world and may triple in incidence by 2025 according to a 2009 report by the American Optometric Society. Retinal diseases could find a “reasonable solution” in the technology, said Jonathan Victor, a professor in the department of neurology and neuroscience at Weill who was familiar with, but not involved in the research. “It’s a major step, it’s elegant, and it works,” he said.


  3. Default

    Quote Originally Posted by waltky View Post
    Three blind mice can now see how they run...

    Blind Mice Given Sight After Device Cracks Retinal Code
    Aug 13, 2012 - Blind mice had their vision restored with a device that helped diseased retinas send signals to the brain, according to a study that may lead to new prosthetic technology for millions of sight-impaired people.
    that is great.

    however, most blindness is not in affluent western nations - and can easily be fixed.

    in fact - according to the Fred Hollows Foundation, the world bank has identified cataract surgery as one of the most cost effective uses of public health funds

    Last edited by cassandrabandra; Aug 14 2012 at 01:52 AM.
    "An era ends when its illusions can no longer be sustained" - Arthur Miller

  4. Cool

    Granny says get yer eyes checked...

    Glaucoma, A Stealth Disease And Major Cause of Blindness
    September 26, 2012 - Glaucoma is a major cause of blindness around the world, but especially in developing countries. The World Health Organization says glaucoma is a greater public health challenge than cataracts, because the blindness caused by glaucoma is permanent.
    If you think you are not at risk for glaucoma, think again. Glaucoma is a disease that steals the sight of people around the world -- and they typically don't even know they have the disease until it has permanently destroyed at least 40 percent of their vision. Dr. Alan Robin specializes in treating glaucoma. "It's the leading cause of blindness in the United States. In Hispanics and in African-Americans, it’s the second leading cause of blindness," said Robin.

    In China and in India, glaucoma is the second leading cause of blindness. "The glaucoma you see in sub-Saharan Africa is a much more aggressive, much more blinding disease than the glaucoma we see in Americans or even African-Americans in the United States," he said. Dr. Eric Fleischer sees these racial differences at Medstar Washington Hospital Center. "Pretty much anybody who has ancestry in Africa has an increased chance for developing glaucoma," said Fleischer.

    Age is another risk factor for glaucoma, although people of all ages can get it. As Dr. Robin explains, it's a group of diseases that commonly produce pressure in the eye. "An eye is sort of like a watch. And behind the face of the watch that has the numbers, fluid is made. It goes through your pupil and into the front of the watch between the numbers or the face and the crystal. There's an area around the edge of the watch that drains the fluid," he said.

    When that drain is clogged, the fluid can't leave the eye as fast as it is produced. The rising pressure within the eye damages and eventually kills the optic nerve. The result is blindness. The process is usually so painless and subtle, people don't notice it. "Typically they'll notice if they bump into door frames, because they've lost their peripheral vision, or they'll start having car accidents because they don't see a car to one side or the other," said Fleischer.

    Fortunately, glaucoma can be easily diagnosed. The simplest test measures peripheral vision. That's because with glaucoma the side vision is the first to go. The good news is that, if caught early, glaucoma can be managed. "It's not preventable, but it's treatable," said Robin. Glaucoma is not reversible, but, as researchers learn more about it, they grow more hopeful that glaucoma can one day be cured or even prevented.


  5. Thumbs up

    Glaucoma is best caught and treated early...

    Early Detection And Treatment A Must For Glaucoma Patients
    October 03, 2012 - Glaucoma is not one disease, but a group of diseases that can cause permanent blindness if left untreated. Just as there are different types of glaucoma, there are different treatments.
    Glaucoma robs people of their vision. It happens when fluid builds up in the eye, causing so much pressure that it kills cells in the optic nerve. Mary Hyman was diagnosed with glaucoma more than a decade ago. "It was something that came on, and I was not aware," said Hyman. Hyman knew something was wrong when she was playing peek-a-boo with a child. "And I did one of these, and I said, that left eye is blurry," she said.

    There's no cure for glaucoma, but it can be controlled by reducing the pressure in the eye. Dr. Eric Fleischer. "There isn't a magic number. That's the tricky part," said Fleischer. The right pressure is different for every patient. And so is the treatment. The first course of treatment is usually with eye drops. "We give the patient a drop, we measure their pressure, and we see if it lowers the pressure. If it won't, then the next step is laser surgery," said Fleischer. The type of treatment depends on the type of glaucoma the patient has.

    Dr. Alan Robin says it can also depend on where the patient lives. "Some drops need to be refrigerated and there's no way in some places like southern India where it's hot, hotter and hottest, or in tropical areas such as equatorial Africa, where you can keep things in refrigeration all the time," said Robin. Cost can also be a barrier to treatment. Dr. Rengaraj Venkatesh is with the Aravand Eye Hospital in India. "In India, when someone seeks health care, they don't come alone. They come with at least one family member. So the cost involved in getting to the hospital is also expensive," said Venkatesh.

    But for those who can get treatment, glaucoma patient Mary Hyman says this: "When you get your physical, get your eyes examined. Even though you might not think you have a problem. Get your eyes examined," she said. Hyman is grateful that she is being treated for her glaucoma. Meanwhile, the World Health Organization says glaucoma is an emerging priority because the number of cases is expected to increase as more people the world over live longer.


  6. Default

    This is an indication that our medical system is responding properly and blindness is now not a problem which can't be treated

  7. Likes waltky liked this post
  8. Cool

    Three blind mice can see again...

    Totally blind mice get sight back
    5 January 2013 - Totally blind mice have had their sight restored by injections of light-sensing cells into the eye, UK researchers report.
    The team in Oxford said their studies closely resemble the treatments that would be needed in people with degenerative eye disease. Similar results have already been achieved with night-blind mice. Experts said the field was advancing rapidly, but there were still questions about the quality of vision restored. Patients with retinitis pigmentosa gradually lose light-sensing cells from the retina and can become blind. The research team, at the University of Oxford, used mice with a complete lack of light-sensing photoreceptor cells in their retinas. The mice were unable to tell the difference between light and dark.


    They injected "precursor" cells which will develop into the building blocks of a retina once inside the eye. Two weeks after the injections a retina had formed, according to the findings presented in the Proceedings of the National Academy of Sciences journal. Prof Robert MacLaren said: "We have recreated the whole structure, basically it's the first proof that you can take a completely blind mouse, put the cells in and reconstruct the entire light-sensitive layer." Previous studies have achieved similar results with mice that had a partially degenerated retina. Prof MacLaren said this was like "restoring a whole computer screen rather than repairing individual pixels". The mice were tested to see if they fled being in a bright area, if their pupils constricted in response to light and had their brain scanned to see if visual information was being processed by the mind.


    Prof Pete Coffee, from the Institute of Ophthalmology at University College London, said the findings were important as they looked at the "most clinically relevant and severe case" of blindness. "This is probably what you would need to do to restore sight in a patient that has lost their vision," he said. However, he said this and similar studies needed to show how good the recovered vision was as brain scans and tests of light sensitivity were not enough. He said: "Can they tell the difference between a nasty animal and something to eat?" Prof Robin Ali published research in the journal Nature showing that transplanting cells could restore vision in night-blind mice and then showed the same technique worked in a range of mice with degenerated retinas.

    He said: "These papers demonstrate that it is possible to transplant photoreceptor cells into a range of mice even with a severe level of degeneration. "I think it's great that another group is showing the utility of photoreceptor transplantation." Researchers are already trialling human embryonic stem cells, at Moorfields Eye Hospital, in patients with Stargardt's disease. Early results suggest the technique is safe but reliable results will take several years. Retinal chips or bionic eyes are also being trailed in patients with retinitis pigmentosa.


  9. Cool

    Hope for diabetes related blindness...

    Scientists Explore Stem Cells to Treat Diabetic Blindness
    February 20, 2013 - Millions of diabetics around the world are threatened with vision loss, a secondary effect of their disease, but researchers are exploring whether stem cells can be used to treat or prevent this diabetic complication.
    Juvenile and adult-onset diabetes result when the body's ability to regulate blood sugar levels goes awry. When the condition becomes chronic, it can lead to cardiovascular disease, damage the kidneys and affect blood flow to the limbs, sometimes requiring amputations. The disease also affects the eyes, according to Alan Stitt of Queen’s University in Belfast, Ireland. Chronically high blood sugar levels can cause a condition called diabetic retinopathy, in which the tiny blood vessels that nourish the retina, the light sensitive tissue at the back of the eye, become blocked or leak. “They then can actually no longer carry the oxygen and the nutrients that the retina requires," Stitt says. "And the retina becomes increasingly dysfunctional as a result of these blood vessels not functioning properly.”

    If left untreated, diabetic retinopathy can lead to partial or total blindness. Stitt, who directs the Queen's University Center for Vision and Vascular Science, is participating in a European-led study called Repair of Diabetic Damage by Stromal Cell Administration (REDDSTAR). Researchers from the U.S., Northern Ireland, Germany, the Netherlands, Denmark and Portugal are also taking part. Each team is trying to prevent and minimize damage to a particular organ as a result of diabetes. The scientists are using adult stem cells isolated from bone marrow, the spongy tissue inside bones. Stem cells are master cells that can be coaxed to morph into any type of tissue cell in the body.

    In Stitt’s laboratory, the stem cells are being injected directly into the eyes of mice bred to have diabetic retinopathy. So far, he says, the results are encouraging, showing signs that the progression toward blindness can be halted as the tiny retinal blood vessels are repaired and regenerated by the stem cells: “They are very clever cells, because what we know from the evidence we’ve got is that they seem to have this ability to go to where the tissue needs them to go," Stitt says. "So they recognize where there’s not enough blood vessels and they can actually then participate in the blood vessel regrowth.”

    Current treatments for diabetic retinopathy, including laser surgery to stop retinal leakage, are directed toward patients with advanced disease. Such medical interventions are painful, costly and frequently unsuccessful. Stitt expects to begin human trials with the potentially eyesight-saving stem cell therapy in about two years.


  10. Cool

    New test for river blindness...

    Researchers Develop Simple Test for River Blindness
    February 28, 2013 - Diagnosing the tropical parasitic illness Onchocerciasis, also known as river blindness, might soon be as easy as testing a urine sample. Such a simple test would permit more effective diagnosis and treatment of a disease that now afflicts nearly 18 million people around the world.
    People call Onchocerciasis "river blindness" because it’s caused by the bite of a parasitic-worm-infected black fly that lives near rivers. The illness is most common in sub-Saharan Africa, although it also exists in parts of Yemen and in Central and South America. The river blindness parasite has an active and inactive phase, making it difficult to treat the disease. During its active phase, the female worm produces millions of microscopic eggs that migrate to different tissues throughout the body. Infection of the eyes can lead to blindness. The disease is usually treated with the antiparasitic agent Ivermectin, which lowers the number of eggs produced by the worm, and an antibiotic, doxycycline, which sterilizes it.

    But according to Daniel Globisch, a researcher at Scripps Research Institute in California, it is difficult to determine when the worm is active. That information would help health care providers know whether their treatment is effective or not. It would also reduce the risk that wasteful use of antibiotics might promote drug resistance in the river blindness parasite. Currently, Globisch says, the only way is to be certain that the worm is active is to do a skin biopsy to look for signs of the parasite. “This is very invasive and also painful and really uncomfortable for the people. And that’s why a non-invasive diagnostic is as important,” Globisch said.

    Globisch and colleagues think they found one. They have identified a single biomarker produced by the worm - a chemical that sends signals from one nerve cell to another - that is present in the patient's urine during the active phase. “The single marker is linked to the worm’s lifecycle. And that is why we believe this is the perfect marker to get a test,” Globisch said.

    Globisch says the test would be inexpensive and portable. Infected individuals also suffer severe itching and the Scripps scientists are investigating treatments to ease that symptom for as long as patients with river blindness harbor the parasite. An article on a urine test for river blindness is published in the journal Proceedings of the National Academy of Sciences.


  11. Icon6

    Cholesterol drugs may prevent macular degeneration...

    Macular degeneration: Cholesterol drugs 'may save sight'
    2 April 2013 - Eye drops designed to lower cholesterol may be able to prevent one of the most common forms of blindness, according to US researchers.
    They showed how high cholesterol levels could affect the immune system and lead to macular degeneration. Tests on mice and humans, published in the journal Cell Metabolism, showed that immune cells became destructive when they were clogged with fats. Others cautioned that the research was still at an early stage. The macula is the sweet spot in the eye which is responsible for fine detail. It is essential for reading, driving and recognising people's faces. Macular degeneration is more common in old age. It starts in a "dry" form in which the light-sensing cells in the eye become damaged, but can progress into the far more threatening "wet" version, when newly formed blood vessels can rapidly cause blindness.

    Fatty clues

    Doctors at the Washington University School of Medicine investigated the role of macrophages, a part of the immune system, in the transition from the dry to the wet form of the disease. One of the researchers, Dr Rajendra Apte, said the role of macrophages changed and they triggered the production of new blood vessels. "Instead of being protective, they accelerate the disease, but we didn't understand why they switched to become the bad cells," he told the BBC. Normally the cells can "eat" fatty deposits and send them back into the blood.

    However, their research showed that older macrophages struggle. They could still eat the fats, but they could not expel them. So they became "bloated", causing inflammation which in turn led to the creation of new blood vessels. Dr Apte said: "Based on our findings, we need to investigate whether vision loss caused by macular degeneration could be prevented with cholesterol-lowering eye drops or other medications that might prevent the build-up of lipids beneath the retina."

    Clara Eaglen, from the charity RNIB for the visually impaired, said: "This new research is very interesting as it shows that cholesterol-lowering drugs could be used to prevent thousands of people losing their sight unnecessarily from conditions such as AMD [age-related macular degeneration] - the biggest cause of sight loss in the UK. "The more aggressive of the two forms, wet AMD, can take your central vision in as little as three months if left untreated. "Clearly this research is still at an early stage but it will be exciting to watch how it progresses and at some point cholesterol-lowering eye drops may become part of a growing army of treatments for sight-threatening eye conditions."


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