Posts tagged vision
Articles and news from the latest research reports.
How to shrink Berlusconi’s head
To perceive the effect, fix your eyes on the cross in the center of the video. Once the motion stops and the head pictures are flashed on-screen, the image on the left should appear smaller than the one on the right. If you pause the video, you’ll notice that in fact both heads are the same size.
Created by Tim Meese and colleagues at Aston University in Birmingham, UK, the illusion was presented last week at the European Conference on Visual Perception in Alghero, Italy.
(Source: newscientist.com)
In a recent study, investigators at Boston University Schools of Medicine (BUSM) and Public Health (BUSPH) identified a gene linking age-related cataracts and Alzheimer’s disease. The findings, published online in PLoS ONE, contribute to the growing body of evidence showing that these two diseases, both associated with increasing age, may share common etiologic factors.
It was a quiet Thursday afternoon when AS, a 68-year-old woman from a suburb of Chicago, awakened from a nap to the realization that something was terribly wrong.
When AS woke from her nap, she couldn’t find where doors or cabinets were. She couldn’t name or distinguish familiar household objects. She couldn’t read a book or the numbers on her telephone. She couldn’t see where the bedroom wall ended and the door began. Yet when she saw an ophthalmologist, her vision with glasses was 20/20. She and her husband left the ophthalmologist’s office with a referral to see a neurologist, and “wondering what sort of ailment could rob her of her ability to see the bathroom sink, while leaving her with what we typically think of as perfect vision.”
Balint’s syndrome is named after Austro-Hungarian neurologist Rezső Bálint, who first described it. The condition is caused by one or more strokes in certain regions of the brain. It causes three deficits: Difficulty initiating voluntary eye movements (such as following a physician’s finger); inaccurate arm pointing (a patient can see an object, but is unable to pick it up); and constriction of the visual field (ask a patient to look at a parking lot, and all she sees is a lamp post or a car.)
A Loyola University Medical Center paper “is an attempt to inform both our clinical and subjective understandings of Balint’s syndrome through narratives of two patients suffering from this rare and unique neurological disorder.”
What good is color vision in the dark of the deep sea? For some crabs, an ability to see blue and ultraviolet light may mean the difference between chowing down on a good meal versus a toxic one.
A new study published in the Journal of Experimental Biology finds that some seafloor, or benthic, crabs can see in color. But the crustaceans live in darkness of the deep Caribbean where sunlight does not penetrate, making their sensitivity to blue and ultraviolet light mysterious.
(Source: livescience.com)
New research finds that the way that the visual centers of men and women’s brains works is different. Men have greater sensitivity to fine detail and rapidly moving stimuli, but women are better at discriminating between colors.
University of Tennessee Researchers Develop Comprehensive, Accessible Vision Testing Device
Eighty-five percent of children’s learning is related to vision. Yet in the United States, eighty percent of children have never had an eye exam or any vision screening before kindergarten, statistics say. When they do, the vision screenings they typically receive can detect only one or two conditions. Ying-Ling Chen, research assistant professor in physics at the University of Tennessee Space Institute in Tullahoma is working to change that with an invention that makes eye exams inexpensive, comprehensive, and simple to administer.
Studying Everyday Eye Movements Could Aid in Diagnosis of Neurological Disorders
USC-led team has designed a low-cost, easily-deployed method for detecting ADHD, Parkinson’s, and Fetal Alcohol Spectrum Disorder
Researchers at the University of Southern California have devised a method for detecting certain neurological disorders through the study of eye movements.
In a study published today in the Journal of Neurology, researchers claim that because Attention Deficit Hyperactivity Disorder (ADHD), Fetal Alcohol Spectrum Disorder (FASD) and Parkinson’s Disease (PD) each involve ocular control and attention dysfunctions, they can be easily identified through an evaluation of how patients move their eyes while they watch television.
“Natural attention and eye movement behavior – like a drop of saliva – contains a biometric signature of an individual and her/his state of brain function or dysfunction,” the article states. “Such individual signatures, and especially potential biomarkers of particular neurological disorders which they may contain, however, have not yet been successfully decoded.”
Typical methods of detection—clinical evaluation, structured behavioral tasks and neuroimaging—are costly, labor-intensive and limited by a patient’s ability to understand and comply with instructions. To solve this problem, doctoral student Po-He Tseng and Professor Laurent Itti of the Department of Computer Science at the USC Viterbi School of Engineering, along with collaborators at Queen’s University in Canada, have devised a new screening method.
Participants in the study were simply instructed to “watch and enjoy” television clips for 20 minutes while their eye movements were recorded. Eye-tracking data was then combined with normative eye-tracking data and a computational model of visual attention to extract 224 quantitative features, allowing the team to use new machine learning techniques to identify critical features that differentiated patients from control subjects.
With eye movement data from 108 subjects, the team was able to identify older adults with Parkinson’s Disease with 89.6% accuracy, and children with either ADHD or FASD with 77.3% accuracy.
Providing new insights into which aspects of attention and gaze control are affected by specific disorders, the team’s method provides considerable promise as an easily-deployed, low-cost, high-throughput screening tool, especially for young children and elderly populations who may be less compliant to traditional tests.
“For the first time, we can actually decode a person’s neurological state from their everyday behavior, without having to subject them to difficult or time-consuming tests,” Itti said.
One biotech startup wants to restore vision in blind patients with a gene therapy that gives light sensitivity to neurons that don’t normally possess it.
The attempt, by Ann Arbor, Michigan-based Retrosense Therapeutics, will use so-called optogenetics. Scientists have used the technique over the last few years as a research tool to study brain circuits and the neural control of behavior by directing neuron activity with flashes of light. But Retrosense and others groups are pushing to bring the technique to patients in clinical trials.
The idea behind Retrosense’s experimental therapy is to use optogenetics to treat patients who have lost their vision due to retinal degenerative diseases such as retinitis pigmentosa. Patients with retinitis pigmentosa experience progressive and irreversible vision loss because the rods and cones of their eyes die due to an inherited condition. If the company is successful, the treatment could also help patients with the most common form of macular degeneration, which affects nearly a million people in the United States. The U.S. Food and Drug Administration hasn’t approved any therapies for either condition.
A bionic eye has given an Australian woman partial sight and researchers say it is an important step towards eventually helping visually impaired people get around independently.
Dianne Ashworth, who has severe vision loss due to the inherited condition retinitis pigmentosa, was fitted with a prototype bionic eye in May at the Royal Victorian Eye and Ear Hospital.
"It was really funny when it switched on I was waiting, waiting … I had these goggles on and I didn’t know what to expect, and I don’t know if anyone did know what I was going to see … Then all of a sudden I went ‘yep’ I could see a little flash and it was like a little, I suppose, a splinter … There were different shapes and dark black, lines of dark black and white lines together … Then that turned into splotches of black with white around them and cloud-like images … I can remember when the first bigger image came I just went ‘Wow,’ because I just didn’t expect it at all but it was amazing," she said.
The bionic eye, designed, built and tested by the Bionic Vision Australia, a consortium of researchers partially funded by the Australian government, is equipped with 24 electrodes with a small wire that extends from the back of the eye to a receptor attached behind the ear.
Like a melody that keeps playing in your head even after the music stops, researchers at the University of Illinois’s Beckman Institute have shown that the beat goes on when it comes to the human visual system.
In an experiment designed to test their theory about a brain mechanism involved in visual processing, the researchers used periodic visual stimuli and electroencephalogram (EEG) recordings and found, one, that they could precisely time the brain’s natural oscillations to future repetitions of the event, and, two, that the effect occurred even after the prompting stimuli was discontinued. These rhythmic oscillations lead to a heightened visual awareness of the next event, meaning controlling them could lead to better visual processing when it matters most, such as in environments like air traffic control towers.