"Our evidence suggests that the key factor is being outdoors, and that it does not matter if that time is spent in having a picnic or in playing sport," Dr. Kathryn A. Rose told Reuters Health. "Both will protect a child's eyes from growing excessively, which is the major cause of myopia."
Myopia has become increasingly common in recent decades, with more than 80 percent of people in some highly-educated groups being nearsighted, Rose of the University of Sydney and her colleagues point out in the journal Ophthalmology. Work that requires a person to focus on something close up -- for example reading -- has been proposed to cause nearsightedness, they add.