Parents used to tell their kids to eat their carrots for good eyesight. While good nutrition is always important, scientists now offer equally simple and beneficial advice: Go outside. They recommend two hours of sunlight a day to help children avoid developing myopia.
Time spent outdoors can actually help prevent nearsightedness. Is this true no matter where you live?
- Time outdoors reducing the likelihood a child will become nearsighted is something that almost all research groups agree on, no matter where they are in the world — which is really unusual because what causes nearsightedness has been a subject of controversy for a few hundred years.
What about the outdoors prevents myopia? Is it brighter light, exercise, vitamin D?
- Our preliminary data supports the hypothesis that it’s because the light is brighter. That creates a release of dopamine from the retina, and that dopamine slows down the growth of the eye, keeps the eye smaller and prevents or lowers the risk of becoming myopic. Vitamin D may still have a small part to play.
Is it possible to recreate that bright light indoors?
- The idea of a glass-cube classroom is being tried in Asia. That may be one of the strategies that becomes something schools are willing to adopt, making the indoor light environment brighter.
- From what can be told though, the amount of light that you need to get the goodness of time outdoors has to come from outdoors right now.
- Tell kids: Go outside. Get the extra benefits of a little physical activity, the extra benefits as far as general health goes, the physical activity. Don’t forget sunscreen. Don’t forget sunglasses. Have fun.
How do you balance greater exposure to outdoor light with protection from UV rays?
- Ultraviolet rays are harmful to the skin and the eye. People need to remember that spending time outdoors means applying the usual protections as far as skin and eyes go: sunscreen, sunglasses, a hat.
What are the health concerns associated with myopia?
- Beyond the inconvenience of wearing glasses or contacts or having refractive surgery such as LASIK, which has its limitations because corrections change, there are health consequences to being nearsighted: retinal detachment, glaucoma and cataracts are all related to being nearsighted.
- The increased risk is low at low levels of myopia, but it’s still there.
- In Asia, where about 80 percent of children are nearsighted, myopic macular disease is becoming a significant factor in visual impairment and new cases of blindness.
Can parents prevent their children from becoming myopic?
- Well, children should select their parents wisely, because it does start with genetics. Kidding aside, there is a certain genetic risk that’s inescapable.
- In general, the chances that two myopic parents will have a myopic child, at least for European heritage, is about 40 percent.
- But if the child of two myopic parents doesn’t spend much time outdoors, their chance of becoming nearsighted increases to about 60 percent.
- If the same child spends about two hours outdoors every day, the chances of becoming myopic drop to 20 percent.
Is there anything parents can do to help slow the progression of myopia if it already exists?
- The current myopia treatment is low-dose atropine. Atropine is something that’s been used as an anti-myopia therapy for more than 100 years, but usually in a high dose that kids can’t tolerate.
- Researchers have found that very low doses are way more tolerable to kids and also seem to have some benefit. Many eye-care providers offer peripheral optical treatments or low-dose atropine.
What about reading on phones and tablets — doesn’t that strain eyesight?
- While there is some controversy over the role of reading and other close work on computers, smart phones, tablets — all the trappings of school in modern society — we can’t find any evidence that any aspect of what we call “near work” affects a child’s risk of becoming nearsighted or the rate of progression of their nearsightedness.