Why is two hours of outdoor exercise every day helpful in preventing and controlling myopia?

Natural light: The light intensity in the outdoor environment is much higher than that indoors. Studies have shown that the full-spectrum sunlight in natural light helps promote the retina to produce a neurotransmitter called dopamine, which is believed to slow the growth of the eye axis, thereby helping to prevent or control the development of myopia.

Visual distance: When you are outdoors, your eyes need to constantly adjust their focus to adapt to different visual distances, from distant mountain views to nearby objects. This constant change in visual focus helps to exercise the eye's ability to adjust and reduce the strain of adjusting caused by long-term close-up use of the eyes.

Reduce close eye use: Outdoor activities can reduce the time children spend on close activities such as reading, writing, and using electronic devices, which are known risk factors for myopia.

Synthetic vitamin D: Moderate UV exposure can increase levels of vitamin D in the body, which is thought to be involved in eye health and the development of myopia.

Blood circulation: Outdoor activities can increase blood circulation in the body, improve blood supply to the eyes, and contribute to eye health.

For these reasons, many ophthalmologists and education authorities recommend that children and adolescents spend at least two hours a day outdoors. Even just being outdoors without engaging in physical exercise may help prevent myopia or control its progression.

However, it is important to note that outdoor activities should be safe and appropriate while protecting the eyes from the strong sun, such as wearing sunglasses and hats.