Whenever we descend stairs, step down from curbs, or step onto an escalator, we instinctively look downward to see where we are going. Of course, this is all well and good unless you are wearing reading glasses, bifocals, trifocals, or progressive lenses. These magnifying lenses do not pose a problem as long as we look straight ahead, but looking down at stairs and curbs through the bottom section of the lenses can be a disorienting experience. The lenses can blur the floor and ground, making it difficult to see possible hazards and to gauge distances. As a result, falls are more likely to occur. To avoid this problem, glasses with single-vision distance should be worn while walking. Most eye care experts recommend that you have a complete eye exam every one to three years, depending on your age, risk factors and whether you currently wear corrective lenses. To maintain a lifetime of healthy vision, the American Optometric Association recommends a comprehensive eye exam every two years for adults ages 18 to 60, and annual exams for seniors age 61 and older. One study found that people who wear reading glasses, bifocals, trifocals, or progressive lenses were twice as likely to fall as those who did not.