Outdoor light the key to preventing myopia
Children need to spend at least one hour a day outside to help prevent myopia, new Australian research has found.
Researchers at Queensland University of Technology’s School of Optometry and Vision Science tracked the progress of 101 children aged between 10 and 15 years, the age at which myopia typically develops, from 42 Brisbane schools.
The children, 41 of whom were myopic and 60 were non-myopic, wore wristwatch light sensors to record light exposure and physical activity for a fortnight during warmer then colder months to give an overall measurement of their typical light exposure.
Their eye growth was measured, along with OCT images of the choroid to highlight novel eye growth changes in the posterior eye.
Lead researcher, Associate Professor Scott Read, said children exposed to the least outdoor light had faster eye growth and hence faster myopia progression.
“Australian kids generally spend more time outside than kids in many other countries, including some Asian countries with a high incidence of myopia,” Professor Read said.
“Still, in our study one-third of kids spent, on average, less than 60 minutes outside a day. Half of these kids were myopic and a handful of the non-myopic kids in this group looked like they were heading towards myopia during the study.
“Our findings suggest the protective effect of being outdoors seems to be related to light rather than physical activity as the study found no significant relationship with exercise and eye growth.
“While it is hard to completely discount near work, we included factors relating to near work in our analyses and these didn’t appear to be significantly related.”
The researchers hypothesise that outdoor light stimulates the production of factors in the retina including retinal dopamine, which helps to slow eye growth.
The research was first published in Invest Ophthalmol Vis Sci and was also presented at the Australian Vision Convention on 3-4 April.