(Press-News.org) (SACRAMENTO, Calif.) — UC Davis Health System Eye Center research has found that visually impaired individuals and those with uncorrected refractive error — those who could benefit from glasses to achieve normal vision but don't wear glasses — have a significantly greater risk of diminished balance with their eyes closed on a compliant, foam surface than individuals with normal vision.
The research, published in the June 6 issue of JAMA Ophthalmology, suggests that vision may play an important role in calibrating the vestibular system, which includes the bones and soft tissue of the inner ear, to help optimize physical balance. The work provides direction for more targeted studies on how poor vision impacts vestibular balance, and how to better develop fall prevention strategies for those with poor vision.
"We know that vision and balance are highly integrated in the brain, but we don't fully understand the relative contributions of the visual, proprioceptive, and vestibular systems in maintaining balance and preventing falls, especially among the visually impaired," said Jeffrey R. Willis, an ophthalmology resident at UC Davis Health System Eye Center and lead author of the study.
"Our research is the first large scale population study to compare objective measures of physical balance across individuals with normal vision, uncorrected refractive error, and the visually impaired, and the first to link poor vision with diminished vestibular balance," he said. "These results have important implications for improving balance and mobility in the U.S. population and preventing falls."
According to the Centers for Disease Control and Prevention, falls among older adults alone cost the U.S. health care system over $30 billion in 2010. One in three adults age 65 and older falls each year, and of those who fall, 20 percent to 30 percent suffer moderate to severe injuries that make it hard for them to get around or live independently, and increase their risk of early death.
Study methods
To objectively examine the relationship between poor vision and balance, Willis worked with the Dana Center for Preventative Ophthalmology at Johns Hopkins University and senior author Pradeep Ramulu to conduct a cross-sectional study, evaluating data from 4,590 adults aged 40 or older, who participated in the 2001-2004 National Health and Nutrition Examination Survey (NHANES). The national survey, which aimed to assess balance in a nationally representative population, included tests of participants' ability to stand with feet together unassisted under increasing challenging conditions: standing on a firm surface with eyes open and then closed, and standing on a compliant, foam surface with eyes opened and then closed.
Foam-surface testing with eyes opened measured the effects of the visual and vestibular systems to work together to maintain postural balance, while the same test with eyes closed primarily assessed the impact of the vestibular system alone, as visual and proprioceptive inputs were minimized. Balance was graded as pass or fail, with the time-to- balance failure recorded for each of the tests. Participants failed the test when they began to fall, moved their arms or feet for stability, or needed help to maintain balance for 15 seconds while on the firm surface or for 30 seconds while on the foam surface. The researchers also gathered data on each participant's self-reported difficulty with falling during the last year.
The researchers found that participants with visual impairment and those with uncorrected refractive error had significantly higher rates of failing the eyes-closed foam-surface balance test —a proxy for vestibular balance – when compared to participants with normal vision. There was no significant difference in the rate of balance failure during balance tests with eyes opened or eyes closed on a firm surface. In addition, subjects with visual impairment, relative to those with normal vision, were more likely to self-report falling difficulties.
"Future research should focus on better understanding how poor vision may affect the vestibular-ocular reflex, and thus vestibular balance," said Willis. "Studies should also address how poor vision may lead to lower levels of physical and balance activities, as well as on how vision-related fall prevention strategies can be integrated with other fall prevention strategies to more effectively limit falls in our society."
INFORMATION: END
Spindle-shaped inclusions in 3 billion-year-old rocks are microfossils of plankton that probably inhabited the oceans around the globe during that time, according to an international team of researchers.
"It is surprising to have large, potentially complex fossils that far back," said Christopher H. House, professor of geosciences, Penn State, and lead author.
However, the researchers not only showed that these inclusions in the rocks were biological in origin, but also that they were likely planktonic autotrophs -- free-floating, tiny ocean organisms that produce energy ...
ANN ARBOR—Facebook connections can help first-generation college applicants believe in their abilities to both apply to school and excel once they've enrolled, according to a new study from the University of Michigan and Michigan State University.
"We are very excited by these findings, because they suggest that the kinds of interactions supported by Facebook and other social media can play a role in helping young people, especially those who are traditionally less likely to go to college, feel more confident about their ability to get into college and to succeed there," ...
NEW YORK (June 6, 2013) -- Researchers at Weill Cornell Medical College have uncovered a mechanism that guides the exquisite wiring of neural circuits in a developing brain -- gaining unprecedented insight into the faulty circuits that may lead to brain disorders ranging from autism to mental retardation.
In the journal Cell, the researchers describe, for the first time, that faulty wiring occurs when RNA molecules embedded in a growing axon are not degraded after they give instructions that help steer the nerve cell. So, for example, the signal that tells the axon to ...
Decades of drought in central Africa reached their worst point in the 1980s, causing Lake Chad, a shallow lake used to water crops in neighboring countries, to almost dry out completely.
The shrinking lake and prolonged drought was initially blamed on overgrazing and bad agricultural practices. More recently, Lake Chad became an example of global warming.
New University of Washington research, to be published in Geophysical Research Letters, shows that the drought were caused at least in part by Northern Hemisphere air pollution.
Aerosols emanating from coal-burning ...
(MINNEAPOLIS/ST. PAUL) June 6, 2013 – A research team led by pediatric blood and marrow transplantation experts Mark Osborn, Ph.D. and Jakub Tolar, M.D., Ph.D. from the Masonic Cancer Center, University of Minnesota, have discovered a remarkable new way to repair genetic defects in the skin cells of patients with the skin disease epidermolysis bullosa.
The findings, published today in the journal Molecular Therapy and highlighted in the most recent issue of Nature, represent the first time researchers been able to correct a disease-causing gene in its natural location ...
On March 11, 2011, a magnitude 9.0 undersea earthquake occurred 43 miles off the shore of Japan. The earthquake generated an unexpectedly massive tsunami that washed over eastern Japan roughly 30 minutes later, killing more than 15,800 people and injuring more than 6,100. More than 2,600 people are still unaccounted for.
Now, computer simulations by Stanford scientists reveal that sound waves in the ocean produced by the earthquake probably reached land tens of minutes before the tsunami. If correctly interpreted, they could have offered a warning that a large tsunami ...
If one looks only for the shiniest pennies in the fountain, chances are one misses most of the coins because they shimmer less brightly. This, in a nutshell, is the conundrum astronomers face when searching for Earth-like planets outside our solar system.
Astronomers at the University of Arizona are part of an international team of exoplanets hunters developing new technology that would dramatically improve the odds of discovering planets with conditions suitable for life – such as having liquid water on the surface.
The team presented its results at a scientific conference ...
VIDEO:
This 3-D view from the west was derived from TRMM Precipitation Radar (PR) data captured when Andrea was examined by the TRMM satellite with the June 5, 2234 UTC (6:34...
Click here for more information.
Towering thunderstorms are a sign of a strong tropical cyclone, and NASA's TRMM satellite spotted thunderstorms reaching heights of almost 9 miles high within Tropical Storm Andrea. NASA's Aqua satellite provided an infrared view that revealed very cold cloud top ...
Cold Spring Harbor, NY -- In our daily lives, clutter is something that gets in our way, something that makes it harder for us to accomplish things. For doctors and scientists trying to parse mountains of raw biological data, clutter is more than a nuisance; it can stand in the way of figuring out how best to treat someone who is very sick.
Using increasingly cheap and rapid methods to read the billions of "letters" that comprise human genomes – including the genomes of individual cells sampled from cancerous tumors -- scientists are generating far more data than they ...
Remora fish, with a sucking disc on top of their heads, have been the stuff of legend. They often attach themselves to the hulls of boats and in ancient times were thought to purposely slow the boat down. While that is a misunderstanding, something else not well understood was the origins of the fish's odd sucking disc. Scientists at the Smithsonian Institution and London's Natural History Museum, however, have solved that mystery proving that the disc is actually a greatly modified dorsal fin. The research is published in the Journal of Morphology.
The world's eight ...
