Editor’s note: This article is a reprint. First published on December 19, 2016.
Sunlight is good for the body. It was really good. In fact, one study found that people who spend time outdoors in the sun, especially teenagers, have better vision later in life.
Conversely, people who didn’t get much sunlight in their teens or early 20s may experience the opposite effect. Types of visual impairment according to research1 Improvements were seen in endoscopy, a type of myopia.
Researchers from King’s College London, the London School of Hygiene and Tropical Medicine, and other universities surveyed 371 Europeans with myopia and 2,797 people without myopia, all aged 65 and over. did.
Each participant underwent an eye exam and had a blood sample taken to estimate their exposure to ultraviolet B radiation, primarily from 9am to 5pm and from 11am to 3pm. I was interviewed about my health behaviors over the year.
People with the highest exposure to UVB radiation, especially teenagers and young people between the ages of 14 and 29, have a 30% higher risk of nearsightedness, which impedes distance vision, compared to those with the lowest exposure. It was low. However, this link was not intended to prove cause and effect, but merely to indicate an association.
Researchers say myopia is becoming increasingly common and increasingly associated with complications that can ultimately threaten people’s vision and cause complications. are. They added that sun exposure actually has a protective effect, but most people don’t know it.
While myopia is only partially thought to be a genetic problem, the study authors said that while the environment appears to have something to do with myopia, it’s not yet clear what it is. are.
today’s children’s problems
Currently, 80-90% of young people in East Asia have myopia problems, while in Europe and the United States;2 It’s about 40% to 50%. Research shows that it is more common among people with higher education and less common among people who regularly spend time outdoors.
“Increasing time spent outdoors in Taiwanese schools over the past five years has resulted in the prevalence of myopia decreasing for the first time in 40 years,” said vision researcher Dr. Ian Morgan. The Australian National University was not involved in this research.
A study conducted in the UK (which seems to be a good representation of young people around the world) found that not only a fifth of the population who can be called “children” spend 0% of their time outdoors, but also Worse, it turned out to be 75%. They spend less time outdoors than prison inmates.
According to a report by Nature.org, the reason for this phenomenon is that, according to 80% of children, they were “uncomfortable being outside due to insects, heat, etc.” 60% said they did not have transportation to travel to natural areas.
visible light
The study also scrutinized factors such as climate, topography, and geographic coordinates, as some climates are prone to rain and fog. In some parts of the world, innovative methods are being used to deal with mountains that block the use of sunlight.
One of the studies included in this review concluded that for every additional hour spent outdoors per week, the chance of developing myopia decreases by 2%.3
According to U.S. News & World Report, scientists involved in the study are unsure whether the current prevalence of myopathy means that sun exposure has a positive effect on vision. He says he can’t have it. In fact, it may be “visible light.” Dr. Donald Mutti, professor of optometry at The Ohio State University, explained:
“The UVB here seems to be simply a proxy for spending more time outdoors. The current thinking is that bright light outside stimulates the release of dopamine from the retina, and that dopamine slows eye growth. This is to prevent nearsightedness.
Our group’s research shows that being outdoors only affects myopia before it develops. If your child needs glasses, going outside will not affect myopia. ”4
Mutti said he thinks children should spend more time outside, but they should also wear sunglasses and sunscreen. However, these can cause other more serious problems.
whether to wear sunglasses
In reality, “protecting” your eyes from sunlight can do more harm than good, as certain wavelengths of light nourish your eyes. If you shield yourself too often, you won’t be able to absorb the full spectrum of sunlight that would otherwise be entering your eyes, which will not only affect your ability to see, but also affect your brain’s hypothalamus.
The hypothalamus can be thought of as the master control, controlling everything from blood pressure to body temperature. It is responsible for balancing the body’s internal clock and circadian rhythms, and natural sunlight is essential for this process. Without it, the body cannot function normally.
Think of it this way. Lack of light to the eyes, also known as illumination impairment, can be compared to malnutrition of the body. Not only do you need 20 minutes of sunlight on your bare skin every day, but your eyes need it too. Mark’s Daily Apple describes the results of one experiment:
“Researchers seeking to study the relationship between light exposure and myopia exposed chicks to varying amounts of light: normal laboratory lighting at 500 lux; ‘strong’ laboratory lighting at 15,000 lux; sunlight was 30,000 lux.
Only strong laboratory light and sunlight can slow the progression of myopia, and normal laboratory lighting (which is still very bright and very similar to standard office lighting conditions) Myopia could not be adequately protected.
Note that direct sunlight is ridiculously bright (up to 130,000 lux), but just being outside in “full daylight” provides enough light for the retinal dopamine test.
Just be outdoors and the sun will take care of the rest. Being able to see means that light is entering your eyes. It’s okay because the light comes from the sun (it’s bright enough). ”5
However, be careful when going out in the sun. If you consume a diet high in seed oils that are high in linoleic acid (LA), it is best to avoid exposure to strong sunlight during peak hours. This is because seed oil can accumulate on the skin and be oxidized by sunlight, causing irritation and skin damage.
To protect your skin health, eliminate seed oils and processed foods for at least six months to allow your body to eliminate most of these harmful fats. That way, you can get the health benefits of the sun without any harmful side effects. Once you have completely eliminated LA from your diet, you can once again experience sunlight at midday.
Relationship between myopia and other eye diseases
Myopia is measured in diopters (D), just like glasses and contacts. Corrections are preceded by a minus sign (-) and are measured in 0.25 D increments. Myopia of -0.25 or -3.00 is considered mild, 3.25 to -6.00 is moderate, and higher myopia is characterized as high.
Both moderate and high myopia can have “serious vision-threatening side effects” called “degenerative” or “pathological.”
More people are affected by this condition today than just 30 years ago, and its prevalence is increasing steadily and at an alarming rate. In fact, in the early 1970s, it affected approximately 25% of people living in the United States. Thirty years later, that percentage had jumped to 42%.6
Whatever the reason, myopia appears to contribute to the prevalence of other eye diseases, some of which are very serious, such as:
• Cataract — Another study showed that cataracts, which are characterized by the gradual opacity of the eye’s lens and blurred vision, tend to develop earlier in people with advanced myopathy, especially Koreans. . In addition, the results of cataract surgery are also not very successful.
• Glaucoma — Glaucoma, a disease that causes damage to the optic nerve, is often associated with increased pressure within the eye. Even mild myopia increases the incidence of this eye disease.
An Australian study reported that people with myopia are two to three times more likely to develop glaucoma than people without myopia.
• Retinal detachment — The American Journal of Epidemiology reported on a study in which scientists concluded that myopia is a “clear risk factor for retinal detachment.”7 All About Vision says:
“Mildly myopic eyes had a four times higher risk of retinal detachment than non-myopic eyes. Moderately and highly myopic eyes had a 10-fold increased risk.”
The study also noted that about 55% of retinal detachment cases that are not caused by trauma can be caused by myopia.8 Furthermore, people with an elongated eye shape (axial myopia) have a 1.72% higher risk of developing this condition after cataract surgery, compared to a 0.28% higher risk for people with a round eye shape.
Does the food you eat have anything to do with your eye health?
Vitamin D levels also increase when a moderate amount of skin is exposed to sunlight, but the study authors say this is not associated with myopia. The researchers also point out that:
“Encouraging children to spend time outdoors is an attractive option, and intervention studies are underway. It remains unclear which of the many factors that reduce the risk of myopia.
Not only the amount of sunlight your eyes receive, but also the food you eat can affect your vision now and in the future. harvard university health list9 Many nutrients your body needs to optimize your vision, and some foods that provide them:
- Lutein and zeaxanthin are found in several cruciferous foods, including broccoli, Brussels sprouts, collard greens, kale, romaine lettuce, spinach, pumpkin, and eggs.
- Animal-based omega-3 fatty acids are most abundant in wild-caught Alaskan salmon, sardines, and krill. Remember to consume omega-3 in moderation, as it is also a polyunsaturated fat (PUFA) and can be harmful in excess.
- Vitamin A is abundant in apricots and cantaloupes.
- Vitamin C is found in grapefruit, kiwi fruitorange, red pepper, strawberry.
- Vitamin E is found in broccoli spinach.
