Another Reason for Kids to Play Outside
Figuring out why people become nearsighted (myopic), and how to keep them from becoming more so, has been a goal of eye doctors for some time now. Over the years, we’ve tried a wide variety of strategies such as having children wear bifocal glasses or using medications that keep the eye from focusing at near. Unfortunately, these attempts have either been unsuccessful or caused too many side effects to be practical. Meanwhile, the prevalence of myopia has continued to increase. Currently, myopia rates are about 33% in the United States with rates as high as 80% of the population in some Asian countries.
This increase in nearsightedness is a problem not only from the perspective of the time and expense of having to buy your child new glasses every year or two, but also in terms of the difference in lifestyle between needing glasses only for driving or watching an event from afar versus having to put on glasses just to see the alarm clock in the morning. Being more nearsighted also puts them at higher risk of eye conditions such as glaucoma or retinal detachment later on in life.
Fortunately things seem to be changing, both in terms of understanding what causes myopia and in how to keep children from becoming nearsighted. A gene (APLP2) has been found to be associated with myopia in primates, however it only seems to explain a small percentage of the probability that a person will become nearsighted. Of course we’ve long known that myopia rates rise as populations go from more rural to urban living. And, increased myopia has been linked to higher education levels. Still, most of us don’t plan on selecting a mate based on their glasses prescription and then sending our offspring into the wilderness with instructions to “stay away from books.”
Happily, there are other methods. The first, and simplest, is simply letting children play outside more. A 2011 study found that odds of myopia, after controlling for other variables, decreased 2% for each additional hour of time spent outdoors per week. Further studies have been trying to tease out if the effect is related to factors such as the higher level of physical activity associated with being outdoors, the bright, wide-open spaces outside, or possibly the increased exposure to sunlight and consequent higher levels of vitamin D. While the jury is still out on which aspect is most to thank, the effect itself does seem to be real, repeatable, and worth thinking about.
No matter how much we try to send our kids outside and keep them away from video games and “book learning,” many still seem to become nearsighted. For these kids, we’re finally starting to make some progress. Work by Dr. Earl Smith III out of the University of Houston showed that myopic progression can be slowed or stopped through the use of optics that align the image a person sees with the natural curve of their retina (as opposed to glasses which focus a flatter image on the center of the retina). Based on this research, specially designed contact lenses have begun to be used to control myopia in children. Recent research shows that when they are worn by nearsighted children, myopic progression slows by about fifty percent. Though this still isn’t perfect, it is an exciting step forward in terms of a simple solution for slowing the development of nearsightedness.