文/阿里安娜·恩俊·查 译/王恒娟 审订/袁圆

By Ariana Eunjung Cha

近视，又称短视眼，正在成为一种在全球蔓延的疾病。

[2]在美国和欧洲，近二分之一的青年患有近视，这一比例是其祖辈同龄时期的两倍。中国的近视问题更加严峻，青少年的近视率为80%到90%，而60年前该比例仅为10%到20%。

[3]为什么有的人近视（看近物清楚，看远物模糊），有的人直到白发暮年仍然保持1.0的视力？研究人员过去一直认为这主要是由基因决定的，而现在，他们更关注环境因素，更确切地说是特定的环境因素：成长过程中的户外活动时间。

Myopia1myopia近视眼。, or nearsightedness2nearsightedness短视眼。, is becoming a problem of epidemic3epidemic流行性的。proportions for the world.

[2] Roughly half of young adults in the United States and Europe have it, double the percentage when their grandparents were the same age. In China, the trend is even more alarming—with 80 percent to 90 percent of teens and young adults with the condition versus 10 percent to 20 percent 60 years ago.

[3] Researchers used to think that the explanation for why some people become nearsighted (able to see close objects more clearly than those far away)and why some continue to have 20/20 vision420/20 vision美国视力检测标准，相当于中国的1.0视力（在距视力表20英尺或6米处，能够看清“正常”视力所能看到的东西）。until they are old and gray was mostly a function of our genes. These days the focus is on environmental factors—or, more accurately, one specif i c type of environmental factor: How much time you spend outdoors while growing up.

[4] In a new study published in the Journal of the American Medical Association, researchers report that children who spent 40 minutes more time outdoors a day were much less likely to be diagnosed with myopia.The research involved 1,903 children in grades 1 through 12 at a dozen schools in the large southern Chinese city of Guangzhou near Hong Kong.

[5] Half of the schools added one additional 40-minute class of outdoor activities during the day, and parents were encouraged to take their children outdoors after school and during the weekends. The remaining schools,which kept their normal schedule,served as a control.

[6] Led by Mingguang He of Sun Yatsen University, the study team found that after three years 30.4 percent of the children in the first group had myopia versus 39.5 percent of the control group.

[4]发表在《美国医学会杂志》的一项新研究表明，每天户外活动时间增加40分钟，孩子患上近视的可能性更小。该研究在中国南部临近香港的大城市广州展开，选择了1903名学生作为研究对象，他们来自12所学校，年级分布从小学一年级到高中三年级都有。

[5]其中的6所学校每天增加了一节40分钟的户外活动课，同时鼓励家长在放学后和周末多带孩子在室外活动。另外的6所学校则作为控制组，保持原先的时间安排。

[6]在中山大学何明光教授的带领下，该研究小组发现，三年后实验组学生的近视率为30.4%，控制组为39.5%。

[7]这说明近视率相对降低了23%。

[8]近视是指光线进入眼睛后焦点落在视网膜之前而导致视物模糊。现代社会，借助框架眼镜、隐形眼镜和激光矫正手术，近视倒没有带来很大麻烦。……