Screening for impaired vision in older adults: New Canadian guideline

A new Canadian guideline for impaired vision in older adults recommends against primary care screening of older adults not reporting concerns about their vision. The guideline, published in English and French in CMAJ (Canadian Medical Association Journal) by the Canadian Task Force on Preventive Health Care (CTFPHC), is aimed at primary care practitioners.

17 may 2018--Visual impairment describes less than 20/40 vision, which usually cannot be corrected with glasses, contact lenses or vision-related procedures. This level of difficulty with vision can affect quality of life, as well as participation in work, social and leisure activities, and increases the likelihood of injuries from falls and other accidents.
The task force considered the benefits of screening for visual impairment in primary health care and referring patients to optometrists for formal vision testing.
"We found no evidence of benefit to patients aged 65 years or older from being screened for impaired vision as a way to prevent limitations on daily living or other consequences," said Dr. Brenda Wilson, Task Force Impaired Vision Working Group Chair. "The task force therefore recommends against screening for impaired vision in primary care settings for people living independently in the community."
Currently, people must make their own appointments for regular vision screening or if they suspect visual problems. Most provinces in Canada cover comprehensive eye examinations for adults aged 65 years and older by eye care professionals.
The new guideline updates a previous guideline from 1995, which recommended screening for visual impairment in elderly patients with diabetes of at least 5 years' duration. The 2018 guideline is based on the latest and highest-quality evidence on screening, which includes 15 randomized controlled trials involving participants aged 65 years or older. It is consistent with the recommendation on vision screening for older adults from the United States Preventive Services Task Force.
"Although screening does not appear to be effective, we need to look for ways to effectively support older Canadians who do experience visual impairment so that they get the services they need from optometrists or other eye care professionals" said Dr. Brett Thombs, chair of the CTFPHC .

More information: Screening for impaired vision in community-dwelling adults aged 65 years and older in primary care settings, https://doi.org/10.1503/cmaj.171430


Provided by Canadian Medical Association Journal

Study: Taking B vitamins can prevent vision loss

By CARLA K. JOHNSON
CHICAGO, 23 feb 2009-- – Taking B vitamins can prevent a common type of vision loss in older women, according to the first rigorous study of its kind. It's a slight redemption for vitamin supplements, which have suffered recent blows from research finding them powerless at preventing disease.
Age-related macular degeneration is the leading cause of blindness in people 65 and older, with nearly 2 million Americans in the advanced stage of the condition. It causes a layer of the eye to deteriorate, blurring the center of the field of vision and making it difficult to recognize faces, read and drive. There's no cure, but treatment, including laser therapy in some cases, can slow it down.
Preventing it has been more elusive.
"Other than avoiding cigarette smoking, this is the first suggestion from a randomized trial of a possible way to reduce early stage AMD," said William Christen of Harvard-affiliated Brigham and Women's Hospital in Boston, who led the research. He said the findings should apply to men as well.
The women in the study who took a combination of B vitamins — B-6, folic acid and B-12 — reduced their risk of macular degeneration by more than one-third after seven years compared to women taking dummy pills.
The study, involving more than 5,000 women ages 40 and older at risk for cardiovascular disease, appears in Monday's Archives of Internal Medicine.
Allen Taylor, director of the Laboratory for Nutrition and Vision Research at Tufts University in Boston, said the study was strong because patients were assigned at random and followed for a long time. But because the findings were teased out of a larger experiment for heart disease, there wasn't strict categorization of the type and severity of the eye disease, said Taylor, who does similar research but was not involved in the new study.
Among women taking the B vitamins there were 55 cases of AMD. In the placebo group, there were 82 cases. More serious cases, causing significant vision loss, totaled 26 in women taking B vitamins and 44 in those taking dummy pills.
There were too few cases of the most advanced AMD to make claims about vitamins' potential benefits, Christen said.
B vitamins lower homocysteine, a blood substance once thought to raise heart disease risk, but the nutrients weren't helpful for that in the larger study on cardiovascular disease.
The eye's small blood vessels may respond better to B vitamins' effect on homocysteine than the body's large vessels, Christen said.
It's too soon to recommend B vitamins to people who want to prevent age-related vision loss, he said. But people who already have the disease should talk to their doctors about over-the-counter eye-protecting supplements, including vitamins C and E and zinc, which prior studies have shown slow the disease.
Christen and others recommended food sources of B vitamins and folic acid such as meat, poultry, fortified cereals, beans, nuts, leafy vegetables, spinach and peas.
The study was funded by the National Institutes of Health. Vitamins and placebos were provided by chemical maker BASF Corp., which did not participate in the study otherwise. Some of the researchers reported past funding from pharmaceutical and nutritional supplement makers.

Vigorous exercise may help prevent vision loss

Berkeley, CA, 11 feb 2009 -- There's another reason to dust off those running shoes. Vigorous exercise may help prevent vision loss, according to a pair of studies from the U.S. Department of Energy's Lawrence Berkeley National Laboratory. The studies tracked approximately 31,000 runners for more than seven years, and found that running reduced the risk of both cataracts and age-related macular degeneration.

The research, which is among the first to suggest that vigorous exercise may help prevent vision loss, offers hope for people seeking to fend off the onset of eye disease.

"In addition to obtaining regular eye exams, people can take a more active role in preserving their vision," says Paul Williams, an epidemiologist in Berkeley Lab's Life Sciences Division who conducted the research. "The studies suggest that people can perhaps lessen their risk for these diseases by taking part in a fitness regimen that includes vigorous exercise."

A cataract, which is a cloudy opacity of the eye lens, is the leading cause of blindness. More than one-half of people in the U.S. over the age of 65 suffer from some form of cataracts. Age-related macular degeneration, which is damage to the retina, is the leading cause of irreversible vision loss in older white Americans, affecting 28 percent of people aged 75 and older.

The diseases have several known risk factors, such as sunlight exposure and diabetes in the case of cataracts, but few interventions. Now, it appears that vigorous cardiovascular exercise may be one way to derail the diseases.

To conduct the research, Williams analyzed data collected in the National Runners' Health Study, which he established in 1991 to determine the health benefits of running.

In this case, he followed approximately 29,000 male runners and 12,000 female runners for more than seven years. Of these people, 733 men reported being diagnosed with cataracts on a questionnaire filled out at the end of the study. Too few women reported cataracts to track.

Men who ran more than 5.7 miles per day had a 35 percent lower risk of developing cataracts than men who ran less than 1.4 miles per day. The study also analyzed men's 10-kilometer race performances, which is a good indicator of overall fitness. The fittest men boasted one-half the risk of developing cataracts compared to the least-fit men.

A second study found that running appeared to reduce the risk of age-related macular degeneration. In the study, 152 men and women reported being diagnosed with the disease. Compared to people who ran less than 1.2 miles per day, people who averaged between 1.2 and 2.4 miles per day had a 19 percent lower risk for the disease, and people who ran more than 2.4 miles per day had between 42 percent and 54 percent lower risk of the disease.

"These findings are compelling because of the large size of the study, and the fact that we are looking at something that is fairly well defined: vigorous exercise, as opposed to more moderate exercise," says Williams.

Most of the runners in the study exceeded the current public health recommendations for physical activity, which is at least 30 minutes of moderate-intensity activities such as brisk walking five days a week, or smaller doses of more vigorous exercise such as running. It is unclear whether people might also lower their risk for cataracts and age-related macular degeneration by walking.

"We know there are important health benefits to walking, including lowering heart disease risk," says Williams. "It is quite likely that the studies' results might apply to a lesser extent to smaller doses of more moderate exercise."

Williams also adds that further research is needed to explore why there is a link between vigorous exercise and a decreased risk for eye disease.

"We know some of the physiological benefits of exercise, and we know about the physiological background of these diseases, so we need to better understand where there's an overlap," says Williams.

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The studies are published in the January 2009 issue of Investigative Ophthalmology and Visual Science. They were supported in part by grants from the National Heart Lung and Blood Institute.