British children who spend more time outdoors are less likely to become short-sighted according to new research from the Children of the 90s study at the University of Bristol.Short-sightedness (myopia) can affect 25-50 per cent of young people in the West and up to 80 per cent of young people in parts of south-east Asia. More than a third of adults need to wear glasses for the condition, in order to see distant objects clearly - a figure that has doubled over the last 30 years.
Research in Australia and the United States has previously suggested a link between the amount of time children spend in active outdoor pursuits and their chances of needing glasses later in life but it was unclear whether this was due to physical activity, or to simply being outside.
To address this question, Drs Cathy Williams (Bristol) and Jez Guggenheim (Cardiff) and their colleagues at the University of Bristol have followed the occurrence of short-sightedness in over 7,000 boys and girls in the Children of the 90s study at ages 7, 10, 11, 12 and 15 and compared it to the amount of time they spent outside at age 9 and how much physical activity they did at age 11. The time spent outdoors was measured by a questionnaire filled in by the children’s parents and their physical activity was recorded objectively using an activity monitor they wore for a week at age 11.
The researchers found that children who spent more time outdoors at age 8-9 were only about half as likely to become short-sighted by the age of 15.
Other recent research has shown that 80-90 per cent of children in Asia are short sighted, which is thought to be due in large part to the amount of time they spend indoors. This UK study now provides the first direct evidence, based on longitudinal data from a large number of contemporary children and teenagers in south-west England, that spending more time outdoors is associated with less myopia by age 15.
The protective effect of being outside for longer is unrelated to whether the children’s parents were short-sighted or how much time the children spent reading.