You could have poor eyesight because you didn't spend enough time outdoors as a child, according to the conclusion of some studies on short-sightedness published in the Optometry and Vision Science.  Although short-sightedness can easily be corrected with glasses or contact lenses , it's much better to prevent it altogether. This means we should allow the eyes to develop the way they should in childhood. Children need to spend more time outdoors, focusing on distant objects, say the Australian researchers. This gives the eyeballs a chance to develop as they should. According to one study on short-sightedness, the risk of developing short-sightedness is great -- about 60 percent -- in children who get five hours or less per week of outdoor activities. But if they do outdoor activities for 14 hours or more a week, the risk drops to 20 percent. Spending time outdoors can even help people overcome a genetic predisposition   to short-sightedness. Children with parents who are short-sighted can bring down their risk by spending a few hours a day outdoors, suggest the findings from another of the studies presented at the conference. It's being in an outdoor environment that seems to be important, not the type of activity. Studies show that both active and passive outdoor activities have the same protective effect. So encourage children to balance the time they spend reading and studying with time outside. Two to three hours a day outside of school hours is the suggested amount by scientists. If it's hard to find that time, then cut the amount of television and reduce the time they spend on computer games and get kids to take frequent breaks outdoors when reading and studying. We can infer people use contact lenses to   _  .
prevent short-sightedness correct short-sightedness protect their eyes from sunlight decorate their eyes
Question: You could have poor eyesight because you didn't spend enough time outdoors as a child, according to the conclusion of some studies on short-sightedness published in the Optometry and Vision Science.  Although short-sightedness can easily be corrected with glasses or contact lenses , it's much better to prevent it altogether. This means we should allow the eyes to develop the way they should in childhood. Children need to spend more time outdoors, focusing on distant objects, say the Australian researchers. This gives the eyeballs a chance to develop as they should. According to one study on short-sightedness, the risk of developing short-sightedness is great -- about 60 percent -- in children who get five hours or less per week of outdoor activities. But if they do outdoor activities for 14 hours or more a week, the risk drops to 20 percent. Spending time outdoors can even help people overcome a genetic predisposition   to short-sightedness. Children with parents who are short-sighted can bring down their risk by spending a few hours a day outdoors, suggest the findings from another of the studies presented at the conference. It's being in an outdoor environment that seems to be important, not the type of activity. Studies show that both active and passive outdoor activities have the same protective effect. So encourage children to balance the time they spend reading and studying with time outside. Two to three hours a day outside of school hours is the suggested amount by scientists. If it's hard to find that time, then cut the amount of television and reduce the time they spend on computer games and get kids to take frequent breaks outdoors when reading and studying. We can infer people use contact lenses to   _  .
A. prevent short-sightedness
B. correct short-sightedness
C. protect their eyes from sunlight
D. decorate their eyes
Answer: