The prevalence of myopia, otherwise known as nearsightedness, is increasing dramatically in the US and around the world. Also on the rise is the prevalence of severe or high myopia. While simple myopia is correctable with glasses, high myopia increases the risk of multiple serious eye conditions. There is a way to help prevent myopia in our children, which is as simple as having them play outdoors.
What is myopia?
Myopia, or nearsightedness, occurs when the eye grows too long from the front to the back. The lens of the eye functions to focus light onto the retina at the back of the eye. If the back of the eye is too far away from the lens of the eye, as it is in myopia, the images are focused at a point in front of the retina. As a result, people with myopia have blurry vision. Their near vision is ok, but they have very poor distance vision.How much has the incidence of myopia increased?
In the early 1970s, about 25% of the population in the US had myopia. Today, that number has increased to 42%. This is a trend that is happening in many other parts of the world. The World Health Organization (WHO) estimates that half the world’s population may be nearsighted by 2050.
Why is this important?
Being nearsighted, particularly having high myopia, increases the risk of conditions that can cause vision loss and blindness later in life. These conditions include:
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Glaucoma
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Retinal detachment
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Early development of cataracts
What causes myopia?
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Myopia is caused by a mix of genetic or hereditary factors and environmental factors.
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According to several research studies, the amount of time a child spends outside in the daylight plays a significant role in the development of myopia.
What are the signs and symptoms of myopia?
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Blurry distance vision
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Sitting very close to the TV or computer screen
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Holding books very close to the eyes
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Squinting when doing activities that require distance vision
How does outdoor play affect myopia?
Several studies have shown that outdoor time, in sunlight, can prevent or lower the chance of developing myopia, or lower the severity of myopia if it does develop. There are a few things that could contribute to this.
Sunlight –
One of the biggest reasons is exposure to the bright light of the sun. Research has shown that the sun’s rays cause a release of dopamine, which impacts the development of the retina and may slow the elongation of the eye as children grow.
Relaxed focus –
Another thing that can provide benefit is allowing the eyes to relax by allowing a child’s eyes to change focus from nearby to distant objects randomly, over and over again. Excessive near focus, such as staring at a digital screen could be a significant contributor to the development of myopia.
Vitamin D –
Another possible contributor is that more time spent in the sun allows for greater Vitamin D production. There has been research showing that nearsighted people have lower levels of Vitamin D than people with normal eyesight. We need more research to know how much Vitamin D affects the development of myopia.
Next week, we will talk more about myopia and things you can do to help prevent or lessen the severity of this condition in children.
If you have any questions about myopia, please log into your account and send us your question. We are here to help.
Dr. Anita Bennett MD – Health Tip Content Editor