Bifocals: Focus on the Risks
In 1784, Benjamin Franklin created bifocal glasses so he could see clearly up close and far away using the same lenses. He suffered from presbyopia, or loss of flexibility in the eye lenses, as do virtually all people by their 50s.
Despite their obvious convenience, bifocal glasses may be dangerous for the elderly, based on a study in the Journal of the American Geriatrics Society.
Falls in seniors are common and can have severe consequences, such as hip fractures and even death. Researchers examined a possible link between multifocal glasses (bifocals, trifocals or progressive lenses) and risk of falling in more than 150 people ages 63-90. Subjects also were examined to assess different visual abilities while wearing the lenses.
Seniors who wore multifocal glasses (nearly all wore bifocals) were more than twice as likely to fall over one year as those who did not, and even more likely to fall due to tripping, when negotiating a staircase or when away from home. These individuals also performed significantly poorer on tests of depth perception and edge-contrast sensitivity.
As you get older, consider owning two separate pairs of glasses if you have presbyopia - one pair for near vision, the other for distance. Although keeping two pairs may be less convenient, it may save you from a dangerous fall. If you insist on wearing multifocal lenses, remember to be especially careful when traveling outside of your home and on uneven surfaces.
Lord SR, Dayhew J, Howland A. Multifocal glasses impair edge-contrast sensitivity and depth perception and increase the risk of falls in older people. Journal of the American Geriatrics Society 2002:50(11), pp. 1760-1766.
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