Time outdoors may be extra-important for kids, teens and elders

Spending time outdoors is one of summer's delights. Now, eye research suggests it may also be a key to our eye and general health, as long as we avoid over-exposure to sunlight. Although spending too much time outdoors without protection from the sun's ultraviolet (UV) light can damage eyes and skin, new studies show that natural light may be essential for normal eye development in kids and for maintaining healthy body rhythms, also called biorhythms, as we age.

Here's what the new studies say about how to gain health benefits while avoiding risks.

Outdoor Time May Reduce Risk of Nearsightedness

A major eye research journal reports strong evidence that spending about three hours per day outdoors is important for lowering the risk of nearsightedness (also called myopia) in school-age children and young adults. Related studies say that the main factor appears to be that outdoor time increases kids' exposure to natural light. This stimulates a chemical called dopamine in the eye, which regulates normal growth of the eyeball. This is important because when an eye grows too long (as measured from front to back), it cannot properly focus images on the retina, and the child will be nearsighted as a result.

At this time, scientists think that UV light is not needed for normal eye development. So, they think kids can gain the eye health benefits and other pluses of playing outdoors and at the same time protect their eyes from long-term UV damage. Just make sure they wear UV-blocking sunglasses and hats when out in the sun. This goes for teens and young adults, as well.

Elders Need More Natural Light, But Are Getting Less

Research exploring the interactions of light exposure, cataract development and older people's health shows that elders may have both a higher need for natural light and a harder time getting it than do younger people. A part of the natural light spectrum, called blue light, is important for our ability to maintain healthy bodily rhythms. These are also called circadian rhythms or biorhythms.

When the lens in the back of the eye ages, it gradually loses the ability to absorb blue light. When the brain receives less blue light, it produces less melatonin, a substance that regulates sleep-wake cycles. This increases the risk of insomnia and other sleep problems, which can be factors in serious conditions like depression and heart disease. Other studies have shown that when older people have their clouded lenses replaced in cataract surgery, their sleep, mood, and thinking processes improve as well as their eyesight.

Specific recommendations on how cataract surgery, exposure to natural light, and other methods could be used to support older peoples' health should be available soon from medical scientists.

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