Chapter 7. Vision: From Eye to Brain

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By Ruth Williams | The sun’s ultraviolet (UV) radiation is a major cause of skin cancer, but it offers some health benefits too, such as boosting production of essential vitamin D and improving mood. Today (May 17), a report in Cell adds enhanced learning and memory to UV’s unexpected benefits. Researchers have discovered that, in mice, exposure to UV light activates a molecular pathway that increases production of the brain chemical glutamate, heightening the animals’ ability to learn and remember. “The subject is of strong interest, because it provides additional support for the recently proposed theory of ultraviolet light’s regulation of the brain and central neuroendocrine system,” dermatologist Andrzej Slominski of the University of Alabama who was not involved in the research writes in an email to The Scientist. “It’s an interesting and timely paper investigating the skin-brain connection,” notes skin scientist Martin Steinhoff of University College Dublin’s Center for Biomedical Engineering who also did not participate in the research. “The authors make an interesting observation linking moderate UV exposure to . . . [production of] the molecule urocanic acid. They hypothesize that this molecule enters the brain, activates glutaminergic neurons through glutamate release, and that memory and learning are increased.” While the work is “fascinating, very meticulous, and extremely detailed,” says dermatologist David Fisher of Massachusetts General Hospital and Harvard Medical School, “it does not imply that UV is actually good for you. . . . Across the board, for humanity, UV really is dangerous.” © 1986-2018 The Scientist

Keyword: Intelligence; Vision
Link ID: 24993 - Posted: 05.18.2018

By LISA SANDERS, M.D. The young woman rubbed her eyes. The numbers and letters on her computer screen jumped erratically. So did the world around her. This had happened before, but late at night when she was tired, never in the middle of the day. The light from the screen suddenly seemed too bright. And her headache, the one that was always present these days, tightened from a dull ache to a squeezing pressure on the back of her head and neck. Nearly in tears from pain and frustration, the 19-year-old called her mother. She couldn’t see; she couldn’t drive. Could her mother pick her up from work? The problems with her eyes began in grade school. Two years earlier, she nearly went blind. All she could see on the left was a rim of light. Everything else was blocked by a big black spot. And then a black dot appeared in her right eye as well. Her parents took her to see many eye doctors, only to be told that there was nothing wrong. One doctor told them that she had “emotional blindness.” The young woman’s vision somehow got a lot better on its own, and though the black dot still obstructed some of her vision, for the last eight months she’d been able to drive — so important in this small mountain town an hour north of San Diego. Now she couldn’t see for what seemed like a different reason. The young woman’s mother arranged for her to go to San Diego to see a neuro-ophthalmologist — a doctor who specializes in vision problems that originate in the brain. When they got to the office, though, the young woman’s vision and headache had returned to their imperfect but baseline state. She told the doctor that her symptoms were least intrusive in the morning; standing and walking seemed to make everything worse. Come back later, the doctor instructed. Mother and daughter walked around and shopped. When a couple of hours later the daughter’s eyes started jumping and her headache worsened, they hurried back to the office. © 2018 The New York Times Company

Keyword: Vision; Movement Disorders
Link ID: 24946 - Posted: 05.07.2018

by Eli Rosenberg At least a dozen and a half people have been diagnosed with a rare form of eye cancer in two locations in North Carolina and Alabama, leaving medical experts mystified about the cause. Ocular melanoma occurs in about 6 out of every 1 million people, according to CBS News, and at least 18 people who have been diagnosed with the eye cancer have connections to Huntersville, N.C., Auburn, Ala., or both locations. Marlana Orloff, an oncologist at Thomas Jefferson University in Philadelphia, is studying the cases with her colleagues, according to CBS. “Most people don’t know anyone with this disease,” Orloff said. “We said, 'Okay, these girls were in this location, they were all definitively diagnosed with this very rare cancer — what’s going on?’ ” Alabama health officials have declined to call the outbreak a cluster yet. Three friends, Juleigh Green, Allison Allred and Ashley McCrary, are among those who have been treated for the cancer, and two of them, Green and Allred, had to get an eye removed. “What’s crazy is literally standing there, I was like, ‘Well, I know two people who’ve had this cancer,’ ” McCrary said. Many of the patients are now traveling to Philadelphia for treatment. The cancer has presented complications for some of the patients, CBS reported. Lori Lee, an Auburn University graduate, had the cancer metastasize in her liver. © 1996-2018 The Washington Post

Keyword: Vision
Link ID: 24926 - Posted: 05.01.2018

Jaclyn was diagnosed with myopia, or nearsightedness, at the age of age four. "I was surprised to learn that she needed glasses," recalled her mother, Ellen Rosenberg, in Toronto. Jaclyn wears glasses all the time at school, where they help her to read and write, she said. Her vision isn't so poor that she trips on things when she takes them off to play sports, Rosenberg said. But in a recent study, more than 30 per cent of young Canadian children walked around with fuzzy vision because of myopia that, unlike Jaclyn's, went undiagnosed. Now experts are exploring a simple way to turn the tide on the worsening problem. Myopia is "increasing globally at an alarming rate," according to the World Health Organization. It affects an estimated 1.89 billion people worldwide, and if rates don't change, that could rise to 2.56 billion by 2020 — a third of the population. Research suggests spending time outdoors protects against myopia. (Pond5) In what they call the first study of its kind in Canada, optometrists in Waterloo, Ont., found the rate of myopia was six per cent in children aged 6 to 8. That soared to 28.9 per cent in children aged 11 to 13. In myopia or nearsightedness, the eyeball doesn't get enough light and elongates. The condition isn't innocuous, said study author Debbie Jones, a clinical professor of optometry at the University of Waterloo and a scientist at the Centre for Ocular Research & Education. ©2018 CBC/Radio-Canada.

Keyword: Vision; Development of the Brain
Link ID: 24884 - Posted: 04.21.2018

Omega-3 fatty acid supplements taken orally proved no better than placebo at relieving symptoms or signs of dry eye, according to the findings of a well-controlled trial funded by the National Eye Institute (NEI), part of the National Institutes of Health. Dry eye disease occurs when the film that coats the eye no longer maintains a healthy ocular surface, which can lead to discomfort and visual impairment. The condition affects an estimated 14 percent of adults in the United States. The paper was published online April 13 in the New England Journal of Medicine. Annual sales of fish- and animal-derived supplements amount to more than a $1-billion market in the United States, according to the Nutrition Business Journal. Many formulations are sold over-the-counter, while others require a prescription or are available for purchase from a health care provider. “The trial provides the most reliable and generalizable evidence thus far on omega-3 supplementation for dry eye disease,” said Maryann Redford, D.D.S., M.P.H., program officer for clinical research at NEI. Despite insufficient evidence establishing the effectiveness of omega-3s, clinicians and their patients have been inclined to try the supplements for a variety of conditions with inflammatory components, including dry eye. “This well-controlled investigation conducted by the independently-led Dry Eye Assessment and Management (DREAM) Research Group shows that omega-3 supplements are no better than placebo for typical patients who suffer from dry eye.” The 27-center trial enrolled 535 participants with at least a six-month history of moderate to severe dry eye. Among them, 349 people were randomly assigned to receive 3 grams daily of fish-derived omega-3 fatty acids in five capsules.

Keyword: Vision
Link ID: 24868 - Posted: 04.16.2018

By Anna Azvolinsky In recent years, scientists have accomplished what previously was saved for miracle workers: they have given blind patients the ability to see better. In 2017, the vision field saw an enormous advance with the approval Luxturna, the first gene therapy to correct vision loss in certain patients with childhood onset blindness. And just last week, researchers reported that a retinal implant allowed a 69-year-old woman with macular degeneration to more than double the number of letters she could identify on a vision chart. “It’s early data but very promising, including one patient with impressive vision gains, for a disease where we don’t have any treatment options,” says Thomas Albini of the University of Miami’s Bascom Palmer Eye Institute who was not involved in the study. The implant, given to five patients with dry age-related macular degeneration (AMD), is a single sheet of retinal pigment epithelial (RPE) cells derived from human embryonic stem cells. Other teams across the globe are inventing their own form of RPE implants, and this type of approach is just one of a plethora of modalities being tested to either slow down or reverse various forms of blindness. © 1986-2018 The Scientist

Keyword: Vision
Link ID: 24858 - Posted: 04.12.2018

Phil Plait I've said this before and I will no doubt say it many times hence: I love optical illusions. For one thing, they're just fun. They warp our sense of reality, and it's really pretty cool to see how easy it is to fool our senses. Some illusions do this in complicated ways that make it hard to understand where our perception goes wrong (and yes, there are entire fields of psychology devoted to figuring out how our brain and eyes physically react to illusions). But others are surprisingly simple, yet are deeply difficult to not see. One of the best is the Müller-Lyer illusion, and the easiest way to describe it is to just show it to you: The two horizontal lines are the same length, but the lower one looks longer thanks to the Müller-Lyer illusion. The two horizontal lines are the same length, but the lower one looks longer thanks to the Müller-Lyer illusion. Despite what your eyes are telling you, those two horizontal lines are the same size! Measure them if you don't believe me. It's an utterly convincing illusion, but an illusion all the same. But still, it's simple, right? Well, visual artist Gianni Sarcone decided to play with this illusion, and created an animated version of it that is simply stunning.

Keyword: Vision
Link ID: 24857 - Posted: 04.12.2018

Dan Garisto Birds can sense Earth’s magnetic field, and this uncanny ability may help them fly home from unfamiliar places or navigate migrations that span tens of thousands of kilometers. For decades, researchers thought iron-rich cells in birds’ beaks acted as microscopic compasses (SN: 5/19/12, p. 8). But in recent years, scientists have found increasing evidence that certain proteins in birds’ eyes might be what allows them see magnetic fields (SN: 10/28/09, p. 12). Scientists have now pinpointed a possible protein behind this “sixth sense.” Two new studies — one examining zebra finches published March 28 in Journal of the Royal Society Interface, the other looking at European robins published January 22 in Current Biology — both single out Cry4, a light-sensitive protein found in the retina. If the researchers are correct, this would be the first time a specific molecule responsible for the detection of magnetic fields has been identified in animals. “This is an exciting advance — we need more papers like these,” says Peter Hore, a chemist at the University of Oxford who has studied chemical reactions involved in bird navigation. Cry4 is part of a class of proteins called cryptochromes, which are known to be involved in circadian rhythms, or biological sleep cycles (SN: 10/02/17, p. 6). But at least some of these proteins are also thought to react to Earth’s magnetic field thanks to the weirdness of quantum mechanics (SN: 7/23/16, p. 8). The protein’s quantum interactions could help birds sense this field, says Atticus Pinzon-Rodriguez, a biologist at the University of Lund in Sweden who was involved with the zebra finch study. |© Society for Science & the Public 2000 - 2018.

Keyword: Animal Migration; Vision
Link ID: 24814 - Posted: 04.03.2018

By James Gallagher Doctors have taken a major step towards curing the most common form of blindness in the UK - age-related macular degeneration. Douglas Waters, 86, could not see out of his right eye, but "I can now read the newspaper" with it, he says. He was one of two patients given pioneering stem cell therapy at Moorfields Eye Hospital in London. Cells from a human embryo were grown into a patch that was delicately inserted into the back of the eye. Douglas, who is from London, developed severe age-related macular degeneration in his right eye three years ago. The macula is the part of the eye that allows you to see straight ahead - whether to recognise faces, watch TV or read a book. He says: "In the months before the operation my sight was really poor and I couldn't see anything out of my right eye. "It's brilliant what the team have done and I feel so lucky to have been given my sight back." The macula is made up of rods and cones that sense light and behind those are a layer of nourishing cells called the retinal pigment epithelium. When this support layer fails, it causes macular degeneration and blindness. Doctors have devised a way of building a new retinal pigment epithelium and surgically implanting it into the eye. The technique, published in Nature Biotechnology, starts with embryonic stem cells. These are a special type of cell that can become any other in the human body. © 2018 BBC.

Keyword: Vision; Stem Cells
Link ID: 24772 - Posted: 03.20.2018

Jason Beaubien The blind have descended in droves on the Bisidimo Hospital in Eastern Ethiopia. The Himalayan Cataract Project is hosting a mass cataract surgery campaign at the medical compound that used to be a leper colony. For one week a team from the nonprofit has set up seven operating tables in four operating rooms and they're offering free cataract surgery to anyone who needs it. On the first day of the campaign it's clear that the need is great. "We have like 700 or 800 patients already in the compound and many more appointed for tomorrow and the day after and the day after that," says Teketel Mathiwos, the Ethiopian program coordinator for the Himalayan Cataract Project. People hoping to get their sight restored are jammed into the compound's main courtyard. Others spill out of an office where optometrists are prepping patients for surgery. The line to get into the actual operating theater extends all the way out of the building, up along a covered walkway and then loops around the corner of another medical building. More still are standing outside the hospital gates. Mathiwos says some patients may have to wait a day or two for the procedure. "They have tents here," Mathiwos says. "We give them the food to eat and we try to take care of them as best as we can." Some of the patients at the Bisidimo Hospital have only one milky eye. Others are blind in both eyes. These patients underwent surgery as part of a campaign run by Himalayan Cataract Project at the Bisidimo Hospital in Ethiopia. The bandages are removed the day after the procedure. Surgeons performed more than 1,600 cataract surgeries during a six-day event in December. © 2018 npr

Keyword: Vision
Link ID: 24688 - Posted: 02.22.2018

By NEIL GENZLINGER Anne M. Treisman, whose insights into how we perceive the world around us provided some of the core theories for the field of cognitive psychology, died on Friday at her home in Manhattan. She was 82. Her daughter Deborah Treisman said the cause was a stroke after a long illness. Dr. Treisman considered a fundamental question: How does the brain make sense of the bombardment of input it is receiving and focus attention on a particular object or activity? What she came up with is called the feature integration theory of attention, detailed in a much-cited 1980 article written with Garry Gelade in the journal Cognitive Psychology, then refined and elaborated on in later work. “Perhaps Anne’s central insight in the field of visual attention was that she realized that you could see basic features like color, orientation and shape everywhere in the visual field, but that there was a problem in knowing how those colors, orientations, shapes, etc., were ‘bound’ together into objects,” Jeremy M. Wolfe, director of the Visual Attention Lab of Harvard Medical School and Brigham and Women’s Hospital, explained in an email. “Her seminal feature integration theory,” he continued, “proposed that selective attention to an object or location enabled the binding of those features and, thus, enabled object recognition. Much argument has followed, but her formulation of the problem has shaped the field for almost four decades.” Dr. Treisman did not merely theorize about how perception works; she tested her ideas with countless experiments in which subjects were asked, for instance, to pick a particular letter out of a visual field, or to identify black digits and colored letters flashing by. The work showed not only how we perceive, but also how we can sometimes misperceive. © 2018 The New York Times Company

Keyword: Attention; Vision
Link ID: 24657 - Posted: 02.14.2018

By Susana Martinez-Conde The latest illusion to go viral in social media depicts two side-by-side stretches of a narrow road, receding in the distance. Both images depict the retreating road at an oblique angle, but the right road’s slant is a lot more pronounced than the slant on the left road. These are two identical photos of a road in Mexico. Credit: Daniel Picon Or is it? In fact, both pictures are identical. As user djeclipz put it, upon sharing the soon-to-become global sensation on Reddit: “This is the same photo, side by side. They are not taken at different angles. Both sides are the same, pixel for pixel.” Advertisement So why do they look so different? The illusion, created in 2010 by the French artist Daniel Picon and entitled “Roads in Mexico,” is a powerful variant of an earlier perceptual phenomenon discovered in 2007 by vision scientists Frederick Kingdom, Ali Yoonessi, and Elena Gheorghiu (all of them then at McGill University). Kingdom and his colleagues dubbed the effect the “Leaning Tower Illusion,” because they first noticed it in a pair of identical photos of the Leaning Tower of Pisa. But, as Kingdom, Yoonesi, and Gheorghiu noted in an excellent Scholarpedia article about their discovery, “the illusion works with any image of a receding object,” including tram lines, train tracks and roads in Mexico. The Leaning Tower Illusion won First Prize in the 2007 Best Illusion of the Year Contest, and is featured prominently in our recent book about the annual competition, Champions of Illusion. An excerpt of Champions of Illusion follows, concerning the bases of this effect: © 2018 Scientific American,

Keyword: Vision
Link ID: 24646 - Posted: 02.12.2018

by Ben Guarino Praying mantises do not perceive the world as you and I do. For starters, they're not very brainy — they're insects. A human brain has 85 billion neurons; insects such as mantises have fewer than a million. But mantises, despite their neuronal drought, have devised a way to see in three dimensions. They have a unique sort of vision unlike the 3-D sight used by primates or any other known creature, scientists at the University of Newcastle in Britain discovered recently. The scientists say they hope to apply this visionary technique to robots, allowing relatively unintelligent machines to see in 3-D. “Praying mantises are really specialized visual predators,” said Vivek Nityananda, an animal behavior expert at the university's Institute of Neuroscience. They are ambush hunters, waiting in stillness to strike at movement. Yet unlike other insects, they have two large, forward-facing eyes — the very feature that enables vertebrates to sense depth. Previous research had suggested that praying mantises use 3-D vision, also called stereopsis. Stereo vision, Nityananda said, is “basically comparing the slightly different views of each eye to be able to work out how far things are from you.” Uncovering the particulars of mantis stereo vision required a lot of patience and a little beeswax. Luckily, Nityananda and his teammates had both. Using the beeswax like glue — in a way that did not harm the insects — they affixed lenses to their faces. The lenses, similar to old-fashioned 3-D movie glasses, had one blue filter paired with one green filter. The mantises then were placed in front of a screen — an insect cinema, the researchers called it. © 1996-2018 The Washington Post

Keyword: Vision
Link ID: 24636 - Posted: 02.09.2018

Research into curious bright spots in the eyes on stroke patients’ brain images could one day alter the way these individuals are assessed and treated. A team of scientists at the National Institutes of Health found that a chemical routinely given to stroke patients undergoing brain scans can leak into their eyes, highlighting those areas and potentially providing insight into their strokes. The study was published in Neurology. “We were kind of astounded by this – it’s a very unrecognized phenomenon,” said Richard Leigh, M.D., an assistant clinical investigator at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and the paper’s senior author. “It raises the question of whether there is something we can observe in the eye that would help clinicians evaluate the severity of a stroke and guide us on how best to help patients.” The eyes glowed so brightly on those images due to gadolinium, a harmless, transparent chemical often given to patients during magnetic resonance imaging (MRI) scans to highlight abnormalities in the brain. In healthy individuals, gadolinium remains in the blood stream and is filtered out by the kidneys. However, when someone has experienced damage to the blood-brain barrier, which controls whether substances in the blood can enter the brain, gadolinium leaks into the brain, creating bright spots that mark the location of brain damage. Previous research had shown that certain eye diseases could cause a similar disruption to the blood-ocular barrier, which does for the eye what the blood-brain barrier does for the brain. Dr. Leigh’s team discovered that a stroke can also compromise the blood-ocular barrier and that the gadolinium that leaked into a patient’s eyes could provide information about his or her stroke.

Keyword: Stroke; Vision
Link ID: 24631 - Posted: 02.08.2018

By Carly Ledbetter Two years after “the dress” divided people over its color, the internet is back with another puzzling wardrobe question. What color are these shoes? Some people think these Vans sneakers look gray and mint (or teal), while others see pink and white. For some, the color changes the more they stare at the shoes: While others are dead-set on the color they see: Twitter user @dolansmalik explained one theory about why the shoes look like different colors to some people: “THE REAL SHOE IS PINK & WHITE OKAY?!” she wrote on Twitter. “The second pic was with flash & darkened, so it looks teal & gray. (depends on what lighting ur in).” Bevil Conway is an investigator with the National Eye Institute who helped contribute to a study on the differences in color perception for the famous “dress” controversy two years ago. He told HuffPost how and why our eyes play tricks on us, in situations like “the dress” and the shoes above. “This is related to the famous dress insofar as both are related to issues of color constancy,” he explained. “Basically your visual system is constantly trying to color correct the images projected on the retina, to remove the color contamination introduced by the spectral bias in the light source.” Conway explained just how and why some people see turquoise in the shoes, while others see pink. “In that manipulated photograph there is a lot of the turquoise cast over the whole image. When you first look at it, after having looked at the pink version, your visual system is still adapted to the lighting conditions of the pink version and so you see the turquoise in the other version, and you attribute this to the shoe itself,” he said. “But after a while, your visual system adapts to the turquoise across the whole of that image and interprets it as part of the light source, eventually discounting it and restoring the shoe to the original pink version (or at least pinker).” ©2018 Oath Inc.

Keyword: Vision
Link ID: 24575 - Posted: 01.26.2018

By Matthew Hutson Imagine searching through your digital photos by mentally picturing the person or image you want. Or sketching a new kitchen design without lifting a pen. Or texting a loved one a sunset photo that was never captured on camera. A computer that can read your mind would find many uses in daily life, not to mention for those paralyzed and with no other way to communicate. Now, scientists have created the first algorithm of its kind to interpret—and accurately reproduce—images seen or imagined by another person. It might be decades before the technology is ready for practical use, but researchers are one step closer to building systems that could help us project our inner mind’s eye outward. “I was impressed that it works so well,” says Zhongming Liu, a computer scientist at Purdue University in West Lafayette, Indiana, who helped develop an algorithm that can somewhat reproduce what moviegoers see when they’re watching a film. “This is really cool.” Using algorithms to decode mental images isn’t new. Since 2011, researchers have recreated movie clips, photos, and even dream imagery by matching brain activity to activity recorded earlier when viewing images. But these methods all have their limits: Some deal only with narrow domains like face shape, and others can’t build an image from scratch—instead, they must select from preprogrammed images or categories like “person” or “bird.” This new work can generate recognizable images on the fly and even reproduce shapes that are not seen, but imagined. © 2018 American Association for the Advancement of Science.

Keyword: Vision; Brain imaging
Link ID: 24518 - Posted: 01.11.2018

Phil Plait I can't think of a better way to start off a new year than scrambling your brains. Just a little bit! But still: enough to make you scratch your head and wonder just what is wrong with that sack of wrinkly pink goo in your skull. One of my favorite optical illusionists is Akiyoshi Kitaoki. He has created hundreds, maybe thousands, of guaranteed brain-melting illusions that will make you swear that what you're seeing is real when it really, really isn't. He has ones that appear to move, that warp your sense of shape and size, destroy your notion of color, and will make you seriously question whether your eyes and brain are talking to each other in any sort of coherent way. He just posted a new one to Twitter, and I love it for its simplicity and efficiency: It creates two illusions at once. Are you ready? Here it is: I don't know about you, but when I look at this I see alternating squarish shapes (Kitaoka called them turtles, so I'll go with that) arranged like a chessboard, with half darked and half lighter. What's disturbing immediately though is that they don't appear to be separated along straight lines. The vertical border of the turtles on the left appear to curve to the right a bit, and the ones on the right curve left. It makes it look like there's a mound or bulge in the middle of the image.

Keyword: Vision
Link ID: 24484 - Posted: 01.04.2018

By Katherine Sellgren BBC News Kids seem to spend endless hours on smartphones, games consoles, computers and tablets these days. Playing on electronic devices certainly doesn't help their waistlines, but do you ever wonder what regular device use is doing to their eyesight? While there isn't much research out there yet about the impact of screens on eyesight - after all the iPhone was first unveiled by Apple in only 2007 - experts are concerned about growing levels of short-sightedness in children. And they suggest the best thing parents can do to prevent it is to encourage youngsters to spend more time outdoors in the sunlight. How short-sightedness is on the rise There has been a massive rise around the globe in short-sightedness - or myopia as it's officially known - over recent decades. "We know that myopia or short-sightedness is becoming more common," says Chris Hammond, professor of ophthalmology at King's College London and consultant ophthalmic surgeon at St Thomas' Hospital. "It has reached epidemic levels in East Asia, Singapore, Taiwan, South Korea, where approaching 90% of 18-year-olds are now short-sighted. "In Europe, it's potentially getting up to 40% to 50% of young adults in their mid-20s who are short-sighted now in Western Europe. It's been gradually rising over the decades of the 20th Century from around 20-30%." Why has it become so much more common? Annegret Dahlmann-Noor, consultant ophthalmologist at Moorfields Eye Hospital in London says lack of natural light seems to be the key issue. "The main factor seems to be a lack of exposure to direct sunlight, because children who study a lot and who use computers or smartphones or tablet computers a lot have less opportunity to run around outside and are less exposed to sunshine and because of that seem to be at more risk of developing short-sightedness." Prof Hammond says: "It may be that there's no coincidence that in East Asian countries, the most myopic ones all correlate with the maths league tables. "These kids are being pushed with very intensive education from a very young age and spend a lot of time indoors studying everything close up and very little time outdoors. © 2017 BBC.

Keyword: Vision
Link ID: 24460 - Posted: 12.28.2017

By Rebecca Keogh Imagine you are at Ikea to pick up a sofa for your new flat. You see one you like, a wine-coloured two-seater with big soft cushions. You imagine what it would look like with your current furniture, and decide that’s the sofa you want. As you continue meandering through the store you find a nice industrial-style lamp and coffee table, so you try to imagine what they might look like with the sofa. But imagining all three items together is more difficult than just imagining the sofa alone. How many pieces of furniture do you think you could rearrange in your mind? Is there a limit to how much we can imagine at once, or is our imagination truly unlimited? viewpoints Limitations to our imagery can constrain what we are able to achieve, both in daily life and in therapeutic interventions. This is the question that my supervisor and I tried to answer in our lab at the University of New South Wales recently. Instead of furniture, we used simple shapes known as Gabor patches, which are essentially circles with lines through them. We also used a visual illusion known as binocular rivalry. Binocular rivalry occurs when two different images are shown, one to each eye, and instead of seeing a mix of the two images you see only one of them, either the image that was presented to the left eye or the image presented to the right eye. Previous work by Joel Pearson (my supervisor) has shown that simply imagining a Gabor patch, or seeing a very weak Gabor patch, will make you more likely to see that image in a subsequent binocular rivalry display. Copyright 2017 Undark

Keyword: Vision; Attention
Link ID: 24452 - Posted: 12.22.2017

By NICHOLAS BAKALAR A new study suggests that vigorous physical activity may increase the risk for vision loss, a finding that has surprised and puzzled researchers. Using questionnaires, Korean researchers evaluated physical activity among 211,960 men and women ages 45 to 79 in 2002 and 2003. Then they tracked diagnoses of age-related macular degeneration, from 2009 to 2013. Macular degeneration, the progressive deterioration of the central area of the retina, is the leading cause of vision loss in the elderly. They found that exercising vigorously five or more days a week was associated with a 54 percent increased risk of macular degeneration in men. They did not find the association in women. The study, in JAMA Ophthalmology, controlled for more than 40 variables, including age, medical history, body mass index, prescription drug use and others. The authors write that excessive exercise might affect the eye’s choroid, a sensitive vascular membrane that surrounds the retina, but “epidemiologic studies cannot provide any evidence for the mechanism or pathology.” The authors acknowledge that the study depends partly on self-reports, which are not always reliable, and that it is an observational study that does not prove cause and effect. © 2017 The New York Times Company

Keyword: Vision
Link ID: 24425 - Posted: 12.15.2017