We all need to get a little fresh air now and then. Humans aren’t meant to live in the dark and constant exposure to artificial light has been linked to a lot of problems, including depression and vitamin deficiencies. Now, research is showing that time outdoors is vital to our eyesight, especially in children. A few extra hours spent outside may lower the risk of developing myopia.
Myopia, or nearsightedness, is a very common sight ailment. It means that while objects up close can be seen clearly, objects in the distance appear blurry or are otherwise difficult to make out. The shape of the eye is usually to blame for myopia, typically the cornea is too curved or the eyeball itself is slightly too long. Many people correct myopia with prescription eyeglasses, contact lenses, or corrective surgery.
Rates of myopia, especially in young people, have been steadily rising for years, but until recently, scientists have been unable to pin down one specific correlation.
Myopia is frequently inherited, and therefore not always preventable. However, growing research suggests there is an environmental factor in some cases of myopia, and it appears to be the great outdoors, or lack thereof, that contributes to these diagnoses.
Kids and myopia
Myopia typically develops around age 12, but over the years we’ve been seeing increasingly younger children needing prescription eyeglasses. Some of this may be attributed to more attentive eye exams, but some of it is believed to be linked to the increasing amount of time children spend focusing on close-up text and objects from books and technology. For years, there has been a known link between education level and myopia rates.
But new research is going one step further. Several new studies have found a potential link between spending time outdoors and a decreased risk of myopia. One study in particular found that just one extra hour of outdoor time per week reduced a child’s risk of myopia by more than 2 percent.
Spending time outdoors is good for all of us, but the myopia benefits appear to be preventative only, and therefore most applicable to young children and preteens. Once a child has myopia, time spent outdoors cannot reverse it, though it may slow progression.
What’s the connection?
So why this link between playing outside and lower rates of myopia? It may be as simple as taking a break from the computer screens and books and giving the eyes a chance to rest. Some research suggests that giving your eyes extra time to refocus on distant objects is helpful in preventing eye strain, and outdoor environments tend to have a wider range of visible objects for the eyes to focus on.
There also appears to be a connection between the natural brightness of the outdoors and slower eye growth. Visible light from the sun can stimulate the release of dopamine from the retina, slowing eye growth. This in turn may prevent the forms of myopia that come from elongated eyeballs.
We’ve known for years that people who grow up with a lot of outdoor time experience lower levels of myopia, but only recently have we been able to start zeroing in on what the actual connection is.
What is visible light?
Light is necessary for sight, but it can be a blurry concept. When most people think of light, they picture the absence of darkness, but light comes in many different forms (or wavelengths). The sun exposes us to many kinds of light, only some of which are considered visible. When someone suffers from myopia, prescription glasses correct the vision problem by helping the eye refract the incoming light properly to produce a clearer image.
The sun gives off three kinds of light: infrared, visible and ultraviolet. Visible light accounts for all the light we can see, and it typically has wavelengths that exist between infrared and ultraviolet. It appears to be this visible light that is responsible for the noted benefits of outdoor exposure.
Eyes and UV rays
None of the research posits any link between UV rays and myopia. It is still recommended that children and young adults protect their eyes from the sun by wearing protective clothing like hats and UV-blocking sunglasses. Eye protection should be worn as frequently as possible for the best preventative effects, but the summer months are particularly crucial. So don’t be afraid to send children outdoors for some healthy sun exposure, just make sure their eyes are protected so they can enjoy the benefits of sunlight without being exposed to the risks.
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