Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.See all posts »
Single Lens Distance Vision Glasses & Outdoor Falls
I’ve noticed that wearing bifocals is awkward when skiing or hiking if I need to look down. When I am looking at my feet through the lower portion of the eyeglasses, the image is blurred, because the lens is set for reading, not a distance of four to five feet. If I need to look at something that falls in my line of sight where the top part of my glasses lenses meet the lower part, then it is impossible to focus. Most of the time, this isn’t a problem, but I still find myself making the occasional physical stumble because I sometimes can’t see very well because of the bifocal lenses. This was a problem recently trekking in Nepal, where a fall on a rocky trail would have carried more severe consequences than tripping in my backyard. So, my solution: when hiking, I switch to single lenses set for distance, and when skiing with goggles, I jettison my glasses altogether, because I get a touch of refraction from the goggles themselves.
I just came across an article in the British Medical Journal entitled “Effect on falls of providing single lens distance vision glasses to multifocal glasses wearers: VISIBLE I randomised controlled trial” (BMJ, 2010:340:c2265doi:10.1136/bmj.c2265). I say “bravo” to Mark Haran, a rehabilitation medicine physician, and his co-authors. These authors conducted a study to determine whether the provision of single lens glasses to older wearers of multifocal glasses would reduce falls. This took place in New South Wales, Australia. The study included 606 regular wearers of multifocal glasses, with a mean age of 80 years. The participants were included if they had an increased risk of falls, as determined by a fall in the previous year, a timed “up and go” test (a test that evaluates mobility) in excess of 15 seconds, or outdoor use of multifocal glasses at least three times per week. Approximately half of the participants received single lens distance glasses to replace their multifocal glasses and were instructed to wear them for walking and outdoor activities.
The results showed an eight percent reduction in falls in the single lens distance glasses group, as compared to persons who kept on using their multifocal glasses. The authors concluded that with appropriate counseling, provision of single lens distance glasses for older wearers of multifocal glasses who take part in regular outdoor activities is an effective falls prevention strategy. However, the authors note that the intervention may be harmful in multifocal glasses wearers with low levels of outdoor activities, if losing their ability to focus on near objects turns out to be detrimental or dangerous.
These findings make a great deal of sense. It is not a great imposition to carry an extra set of glasses for near vision, and certainly much better than falling on the trail and breaking a hip. As more elders find ways to continue their recreation and adventures in the outdoors, it would be wise for them to use their distance glasses for activities like hiking, biking, skiing, and so forth, and bring along their bifocals for when they are not on the move or in a position to fall.
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