Outdoor Activity May Protect Children from Myopia
Research suggests that sun exposure may either increase depth of field or inhibit eye growth
FRIDAY, Jan. 9 (HealthDay News) -- Children with higher levels of outdoor sport and leisure activities may have a lower risk of myopia, according to several studies presented at the 12th International Myopia Conference held in Queensland, Australia, July 8 to 11, 2008, and published in the January issue of Optometry and Vision Science.
In one study, Kathryn A. Rose, M.D., of the University of Sydney in New South Wales, Australia, conducted a cross-sectional school-based study of more than 4,000 children and found that a combination of low levels of near-work with high levels of outdoor activity was associated with the most hyperopic mean refraction while a combination of high levels of near-work with low levels of outdoor activity was associated with the least hyperopic mean refraction.
In a second study, Jane Gwiazda, Ph.D., of The New England College of Optometry in Boston, and a colleague studied 191 children and found that children with myopia spent significantly fewer weekly hours than children without myopia playing outdoors (8.3 hours versus 12.6 hours) and significantly more weekly hours watching television (12.5 hours versus 8.4 hours).
"There were no associations between indoor sport and myopia," Rose and colleagues conclude. "The apparent protective effect of time spent outdoors may be mediated by light causing either a reduction in pupil size, which will increase depth of field and lessening blur, or by inhibition of eye growth through light-induced release of dopamine."