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NEW YORK (Reuters Health) - People whose vision has deteriorated in both eyes are less physically active than people without vision loss, according to a new study, potentially putting them at risk for poor health.
The results are not surprising, but are a reminder that it's important to help people with vision loss regain activity safely, say the study's authors.
It's not clear from the study if the loss of vision is leading to less activity or if inactivity contributes to vision loss.
Dr. Pradeep Ramulu, the senior author of the study, said it's possible it could work both ways, but "I think the answer is probably falls or fear of falling."
Ramulu said people with poor vision are more likely to fall, and either that experience or the fear of being injured might be keeping people tied down.
He and his colleagues have observed in an earlier study that people with vision loss drive less, and they wanted to see whether they also get around less in physical ways.
The group looked to data from a large national study that surveyed adults over age 40 on their health and lifestyle.
More than 1,400 people in the study also underwent vision exams and wore an accelerometer on a belt for a week to measure how many steps a day they took.
The vision tests measured people's visual field - how well they can see objects outside of an immediate focal point.
Vision loss from diseases like glaucoma or macular degeneration will narrow people's visual field. This is a different type of impairment than blurry vision, which can be corrected by glasses.
According to the Centers for Disease Control and Prevention, 1.8 million people have vision loss from macular degeneration, 2.2 million people suffer from glaucoma, and another 20 million have a cataract.
1,700 FEWER STEPS PER DAY
In the study, published in the journal Ophthalmology, the threshold for having vision loss was being unable to see at least two out of 19 objects presented in various locations of their peripheral vision.
The researchers found that 88 people had vision loss in one eye and 59 had vision loss in both eyes.
People with good vision took about 9,700 steps each day and exercised at a moderate or vigorous level for 20 minutes.
Those who had vision loss in one eye walked 8,000 steps each day and exercised about 15 minutes.
People with vision loss in both eyes took 6,800 steps each day and exercised for 10 minutes.
When the researchers took into account factors that could influence how much people move, such as age and illness, they found that vision loss in both eyes was tied to 17 percent fewer steps per day and 30 percent less activity than people without any loss.
Taking into account these other factors also showed that people with vision loss in only one eye were just as active as people without any vision loss.
"What we found was the impact of vision was very substantial compared to other diseases," Ramulu told Reuters Health.
For instance, he found that people with diabetes had about the same amount of reduction in their physical activity as people with vision loss in both eyes.
James Rimmer, the research director at the Lakeshore Foundation at the University of Alabama at Birmingham, who was not involved in this study, said it's obvious that a loss of vision can make it more difficult for people to get around.
The study "supports what we've known for a while, and that is that people who have physical, cognitive or sensory disabilities have lower rates of physical activity," he said.
Rimmer said that people with vision loss can try to find a walking partner, for instance, to make sure they don't trip.
"When one loses more and more vision there's just more restrictions in the built environment. Streets become harder to navigate, walkways and paths often have obstacles and difficult terrain. So it just adds to the complexity of trying to be physically active," he told Reuters Health.
SOURCE: bit.ly/R8dcAo Ophthalmology, online August 13, 2012.